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1. UART debug connector JP2 PIC32 PIC24_DEBUG_RX__2 ood PIC24_DEBUG_TX__1 GND 3 4221 18 MARS PM Sheet 1 1 6 PIC24_DEBUG_UART LINK_LED Ethernet link activity LINK ACT MA 10 M_LED 1 MBPS DHCP_LED 4 100 Mbps speed GND INS UDD USR_LED4 DHCP_OK INS 4 DHCP OK connection OK 4 User LED 1 lt PIC24 USR_LED2 USR_LED1 x 4 User LED 2 lt PIC32 ki USR_LED2 INS GND 343 ka lest DOIS oO m RECT48 __ ou e y RECT 48 nu Silk and documentation onlu DISPLAY 00D logo Miscellaneous ood 1721713 LS PM Sheet 1 1 6 1 Chip program connector PIC32_ICSP JP3 1 2 3 4 5 SD_MISO 1C32_MCLR 3300 CRS_DU PIC32_PGED1 _PGEC4 PIC32_MCLR PIC32 Micro SD r microSD CARD CDc2 gt CD lt 1 RSU DO USS CLK UDD DI ES NC CD2 CD1 8 SD_CS SD_MOSI SD_MISQ__2 6 5 4 3 2 1 R30 REFCLK GND UDD SD_CD PIC32 PGEC1 PIC32_PGED1 182 E GND Ras BUZZ PHM RXER GND UDD NFC_TX NFC_RX RXD RXD1 GND UDD MCUCOM_SCK PIC32_DEBUG_RX PIC32_DEBUG_TX U8 PIC32MX695F 512L reader connector UDD 3 L O O O c58 NFC UART tantalum RE4 RE3 RE2 RG13 RG12 RG14 REL REO RAZ RAG RGO RG1 RF1 RFQ UR
2. Bus matrix Prefetch buffer cache Interrupt controller 16 bit 3 analog timers comp Peripheral bus 16 bit 5 Input 18 Figure 4 4 PIC32MX architecture 1 The PIC32 comes in similar packages as the PIC24 but with two different TQFP variantions A slightly larger TQFP package 14x14x1 mm instead of 12x12x1 mm is used because it will make it easier to route on the PCB Allocating pins The PIC32 does not have the same remappable peripheral pin feature as PIC24 so the UART and SPI connections must be chosen from a fixed set of pins Although the PIC32 offers many peripheral modules of the same kind many overlap reducing the pin allocating possibilites The Ethernet signals were given the highest priority when mapping pins The high speed signals were given a short route to the Ethernet transceiver which included rotating the microcontroller to minimise trace distance and vias Ethernet details will be discussed in chapter 5 36 CHAPTER 4 MICROCONTROLLERS The remaining signals were easier to connect afterwards given the many unused pins The resulting allocation is shown in the second table in appendix B Necessary connections 0 1 uF VDD CEFC Ceramic CBP Q YN R y Ss RI E mw MR a S C gt al PIC32 E es VDD Vss LE 0 1 pF 38 g o e 0tpF Ceramic z z Q p Ceramic CBP gt gt CBP 0 1 uF 0 1 uF Ceramic Ceramic CBP CBP Figure 4 5 R
3. Code listing 15 5 Function called from main monitoring changes on the card detect pin 15 2 PERFORMANCE 105 15 2 Performance Given a 100 MBit s capable Ethernet controller connected using RMII the performance of the HTTP traffic is determined by the efficiency of the web server and the file system and its I O layer The performance of the web server implementation is not known so in order to determine whether the FatFS I O layer is the bottleneck of the system its performance must be measured Appendix A contains a MPLABX project fatFSTest that allows the read performance of the system to be tested In order to validate the read data a checksum is calculated of the file using the MD5 algorithm and compared against a pre calculated hash value The time spent on calculating the hash sum is substracted from the overall duration How the read test is performed Listing 15 6 on the following page shows the FatFS read performance test function stripped for debugging info original in appendix A Only the function of interest is shown the remaining framework is similar to the one used in the main OOD application The test is started by typing read fileName n on the UART RX line and the progress and result is output on the TX line The test looks for a file in the root folder with the given name and reads its contents in 512 byte chunks The calculated MD5 hash sum will be compared against the contents of a file with the same na
4. NEG reder s 2 4 25 za at a a eS Rs 13 2 3 Specification e s Aria a A dead o aa 14 Physical dimensions 2 2 Common 14 Network saira amp u van aa en wel 14 Power supply 3 a 52 03 222 LL ee a 15 Non volatile memory 222 2 2 Coon 15 Display and frame buffer 16 Microcontr llers amaia ew See A A a a 16 Time keeping s ba goes a a ta ek a ee ed 17 User interfaces aos man a ae g e eTa a aii ee 17 vii viii CONTENTS 2 47 Pinalidesign se AA AA WE IA 17 Design pro ess 2 ae whales 3 a2 2 2 a anne o 19 II Hardware 21 3 Development boards 23 3 1 PIC24FJ256DA210 development board 23 3 2 Graphics Display PowerTip 4 3 480x272 Board 24 3 3 PIC32MX695F512L board LL 24 3 4 ENC28J60 board 00 tA bee ae e E a ee aa 26 3 9 MicroSD board us 4 244 2 ame ee OS Ae ee a a 26 4 Microcontrollers 29 4 1 Communication protocols o e 30 4 2 PIC24EJ256DA210 oia rr o EEE a 31 BEMP cs 132 593 ita da A e bee Be N 32 Integrated graphics controller ooo oo 33 Alloeating pins 127 e ep TRENNT 33 Necessary connections 2 22 Cm nn 34 4 3 PIC32MX695F512L 34 Allocating pins ias AAA 35 Necessary connections os sic ser 0 00000 000000032 36 HA Erratas na Bene a E 36 5 Ethernet 37 51 MI and RMII corria eek dae aha 37 5 20 LANS8720 aa io e a ae 38 Configuration straps n se aca i nA o D AT Oa a A 39 POWE gece LE AAA Ad ES 40 LE
5. broadcast 10 10 10 255 File system Application FatFS Low level disk I O RTC Figure 15 1 FatFS architecture The design of the OOD suggested using a file system to store non volatile data for the 32 bit microcontroller 66 The main reason for using a file system is because of the nature of the web server whose main task is to serve files to clients Another important reason is ease of use HTML files configuration files and pictures can be edited on a desktop computer and transfered directly to the storage medium without any conversion or additional circuitry The only needed hardware is a SD card reader which is an increasingly common peripheral for all computers A file allocation table FAT file system was suggested in 66 mainly since it is the de facto filesystem used on memory cards FAT32 was also suggested over FAT16 since it is a far more common filesystem than FAT16 and it supports far more files and storage space Two FAT32 file system implementations were considered FatFS 43 and Microchip Memory Disk Drive File System 97 98 CHAPTER 15 FILE SYSTEM Library MDD Based on the data rate test results found in a Microchip forum thread 44 where FatFS proved to outperform MDD FatFS was chosen in favour of MDD Although it is not deemed critical to have very fast disk I O times any improvement in efficiency is greatly appreciated It is important to provide a responsive user interface to the user Anoth
6. ARP address resolution protocol ASCIT American Standard Code for Information Interchange BCD binary coded decimal BGA ball grid array BOM bill of materials BSD Berkely Software Distribution CD compact disk CGI common gateway interface CPU central processing unit CSR certificate signing request CSS cascading style sheets DC direct current DHCP dynamic host configuration protocol DMA direct memory access DNS domain name system ECAD electronic design automation EDS extended data space xix XX LIST OF ACRONYMS EMC electromagnetic compatibility ENIG electroless nickel immersion gold EPMP enhanced parallel master port FAT file allocation table GOL graphics object layer GPL GNU General Public License GPU graphical processing unit GRC Graphics Resource Converter GUI graphical user interface HTML hypertext markup language HTTP hypertext transfer protocol HTTPS hypertext transfer protocol secure PC inter intergrated circuit IC integrated circuit ICMP Internet control message protocol ICSP in circuit serial programming IDE integrated development environment IP Internet protocol IPv4 Internet protocol version 4 IPv6 Internet protocol version 6 ITEM the Department of Telematics ITK the Department of Engineering Cybernetics JSON JavaScript object notation LCD liquid crystal display LED light emitting diode LIST OF ACRONYMS Xxi LFN long filename LGPL GNU Lesser General Public License LSB least signific
7. Any number over 0x7f gives unconditional access whereas any other number requires authentication which is performed by the function HTTPCheckAuth This function is given the supplied user name and password which the user must check The function has access to the value returned by HTTPNeedsAuth and returns a similar number any value below 0x80 tells the web server that the user is authenticated This number system can be used to implement an authorisation system or hierarchy No passwords are stored in clear on the OOD neither in flash nor on the file system The OOD will be placed in a place where it can be physically tampered with and it must not be possible for attackers to retrieve passwords It can never be assumed that the owner will not use a password he does not use for 152 CHAPTER 20 TCP IP STACK Random number p455wOrd OK Oxab423a1 2 a nn SHA KW DATABASE hash c62b172e49ff385b3a18 y sat 0xab423a12 c62b172e49ff385b3a18 S HA I 062b172e49ff385b3a18 p455wOrd OK O K log in password Figure 20 4 How adding and checking passwords is performed other services so it is important that his secret stays safe When the owner enters a new password it will always be encrypted using SSL and it is not the password string itself that will be saved on file but a hash The random and hashing functions provided by the TCP TP stack is used to hash the password along with a random number When the user l
8. Software Architecture The software on the OOD is a collection of libraries and other smaller modules tailored for the the needs of the out of office application As much software as possible is re used from libraries and existing code but due to the unqiueness of the OOD a lot of software has to be made from scratch as well Although C compilers exist for the microcontrollers C is language of choice for the development The libraries used contain some optimalised assembly code but no new assembly code is added PIC32 PIC24 Configuration inter mcu File system communication State SPI SPI machine Touch screen PC Graphics TCP IP objects HTTP server RMII Graphics Calendar f drawing Display driver Figure 13 1 OOD software architecture Figure 13 1 shows a diagram of all the major software modules and a simplified illustration of how they communicate Note that there is no core module or operating system centred in either microcontrollers This will be discussed later In the PIC32 most of the work is performed in the TCP IP stack and almost nothing is done outside the stack s repetitive work task In the PIC24 the GUI 87 88 CHAPTER 13 ARCHITECTURE makes up most of the application code and the PIC24 itself can be seen as an interface in the same way as the web interface Since no critical components run within the PIC24 it can be powered down without affecting the core of the OOD This would nonetheles
9. TSOP II thin small outline package type II UART universal asynchronous receiver transmitter LIST OF ACRONYMS UDP user datagram protocol UI user interface URL uniform resource locator USB universal serial bus UTC coordinated universal time VGA video graphics array xxiii Part I Introduction Figure 1 1 A simple out of office system Professors are at times very hard to get hold of So is reliable information about when they will be back at their offices Wandering the hallways of a university will reveal many doors with sticky notes and the occasional home grown out of office information system with spinning dials or arrays of LEDs Although many of these simple systems fulfil one important need tell people that one is away and when one is likely to return they all lack the possibility to be updated whilst being away Information about one s availability has little value if it is outdated and incorrect With an ability to update the message on the door remotely coworkers and students no longer need to periodically visit the professor s office door to check for his presence Knowing that the information is up to date and can be trusted 3 4 CHAPTER 1 INTRODUCTION students and coworkers can return when the professor has announced his arrival If the system also allows the professor to update his availability status in a very efficient manner chances are he will always notify his coworkers and students whenever
10. callbacks may also need state variables to store their internal state between calls Similarly to the dynamic variable callbacks the POST processing callbacks are given a work buffer in form of a void pointer allowing them store whatever they need packed in a struct The pointer is freed when non NULL when the client disconnects or whenever a new callback is called How this is implemented and used is best explained in the OOD source Authentication and authorisation Only the owner of the OOD should be allowed to visit certain parts of the web UI so that outsiders cannot tamper with the settings In order to separate users from one another the web server must provide a way for the users to authenticate themselves Microchip s web server supports HTTP basic access authentication which is a very simple authentication method that is widely supported 17 The protocol is vulnerable by itself especially since the password is sent in clear which is why it is used in conjunction with SSL The HTTP server can be configured to enforce the use of HTTPS port 443 whenever authentication is required by defining HTTP_NO_AUTH_WITHOUT _SSL in TCPIPConfig h The server depends on two user supplied functions to determine whether a requested path needs authorisation and whether the supplied credentials should be accepted HTTPNeedsAuth is supplied with the requested path and should return a value that determines whether the path requires authentication
11. e Notify the office occupant by sending a short notification e Book a meeting Different environments would have different needs and some OOD owners would probably not need the possibility of letting passer bys sending messages and book appointments from the menus These menus should be possible to be disabled and customised If the menu is abandoned it should revert to the main page showing name portrait and status after a suitable timeout Network connection and web server The web server serves two purposes Letting the owner update his status and configure the OOD and letting coworkers see his current status without having to visit the office Whereas the display only provides some of the features and menus the web Ul should provide all the possible configuration possibilities The web UI should be possible to use from both desktop computers and mobile devices It is important for the owner to be able to do a minimum of updating his status using a mobile device This operation should also be quick and effortless to do so that the owner does not fall into a habit of not keeping his status up to date The public interface should provide the same information as that displayed on the display of the OOD Name title availability status and portrait It can also optionally include an interactive calendar showing the owner s future availability and possibly also allow users to book appointments If the access to the public interface is
12. s peripheral library s RTCC routines are used to manipulate the RTCC registers which takes care of low level details However the date and time data still needs to be converted to and from binary coded decimals BCDs The macros in listing 19 3 are used for this ood pic32eth X dateTime h 33 define BCDToDec bed 10 bed gt gt 4 bed amp Ox0f 34 define decToBCD dec dec 10 lt lt 4 l dec 10 Code listing 19 3 BCD conversion macros Since the OOD does not have a battery it is not possible to keep the current time between power cuts The OOD therefore relies heavily on getting time updates from SNTP since keeping time is such an important feature SNTP is used to get the time at boot and regularly at a user defined interval With RTCC there is really no need to synchronise time frequently and given the SNTP support the RTCC can even be removed entirely It is nonetheless kept since the only hardware dependency is a cheap 32 768 Hz crystal The OOD does not have any means of keeping track of daylight savings time so the user has to manually set the coordinated universal time UTC offset in the web UI This can be improved but has not been prioritised TCP IP stack The 32 bits microcontroller s main purpose is to provide a web UI to the user and in order to to so it needs a web server A web server or a HTTP server handles requests from clients and returns data using the HTTP prot
13. 156 157 f_close amp f 158 return 159 Ip 160 Do not include MD5 hashing work in duration 161 duration ReadCoreTimer prevTimestamp 162 163 MD5AddData amp md5 buffer sizeof buffer 164 165 numBytesReadTotal numBytesRead 166 prevTimestamp ReadCoreTimer 167 168 169 f_close amp f 170 171 unsigned char md5Result 16 172 puts Computing MD5 hash 173 MD5Calculate amp md5 md5Result 174 175 size_t fileNameLen strlen fileName char hashFileName malloc fileNameLen 4 1 sizeof char 176 JE Code listing 15 6 FatFS read performance test routine 15 3 FILE SYSTEM STRUCTURE 107 178 179 180 181 182 183 184 185 186 187 188 189 190 191 202 203 204 205 fatFSTest main c continued if lhashFileName return strcpy hashFileName fileName strcpy amp hashFileName fileNameLen md5 if retVal f open amp f hashFileName FA READ f free hashFileName return free hashFileName unsigned char md5ExpectedResult 16 1 unsigned int numBytesRead if retVal f read amp f md5ExpectedResult sizeof md5ExpectedResult amp numBytesRead af f_close amp f return il f close amp f if Istrncmp md5Result md5ExpectedResult sizeof md5Result puts MD5 hashes match else puts MD5 HASHES DO NOT MATCH Code listing 15 6 FatFS read performance test routine co
14. 18 Graphics library 121 18 1 Configuration 2 22 Coon nn 123 18 2 Using the graphics library o 125 GOL aa ika a ar Bra nee 125 Fonts and other resources 2 2 2 2 nn nn nn 127 18 3 Using a state machine with GOL 128 19 Calendar and availabilities 131 19 1 Appointment and availability format 131 19 2 File stru tufe a od 8 eS EER Se ee eee ay 132 19 3 Real time clock and calendar o nn 134 20 TCP IP stack 135 20 Architecture x 4 2 A e Ra tia Gah rn 136 CONTENTS 20 2 Stack configuration o Setting MAC and IP addresses o 20 3 Using therstack 00888 PPG ata en ee d 20 4 Modifications Lu 4 ae a a na ee 20 5 HTTP server 3 a e a ee ee AE How the server works o o Batl S Support ura a ra Dynamic variables oo on GET and POST processing o Authentication and authorisation Gonfisur tion bis ts a ae dal ais Se Sek e dt Using MPFS to convert files 2 0 00 0 20 6 OSL miooo aS PRESS Ae A il koki b BERS Generating and using SSL certificates 2 2 22 220 207 SNIP clients au ra kn a ae a a ee a Modifications HH fv thei ke SH SK ee ee A 21 Inter microcontroller communication 22 Other modules and software 22 1 Settings 22 2 Tick module 22 3 UART and debugging 2 2 2 nn nn 22 4 N
15. Applications help 15 The BSD 2 Clause License http opensource org licenses BSD 2 Clause Accessed Jun 29th 2013 16 IETF RFC 3621 Simple Network Time Protocol SNTP August 1992 17 IETF RFC 2617 HTTP Authentication Basic and Digest Access Authen tication June 1999 18 MCP1650 51 52 53 http ww1l microchip com downloads en DeviceDoc 21876B pdf 2004 Accessed Feb 14th 2013 19 IEFT RFC 3627 The application json Media type for JavaScript Object Notation JSON 2006 20 GNU General Public License https gnu org licenses gpl html 2007 Accessed Jun 29th 2013 21 GNU Lesser General Public License https www gnu org licenses Igpl html 2007 Accessed Jun 29th 2013 22 RILVO816ASB 5SI 7SI Datasheet December 2007 23 RSA 1024 bit Encryption not Enough http www pcworld com article 132184 article html 2007 Accessed Dec 18th 2012 24 IEEE Std 802 3 2008 Part 1 2008 25 IEEE Std 802 3 2008 Part 2 2008 26 M29W320DT Datasheet March 2008 27 Section 24 Inter Integrated Circuit IC http ww1 microchip com downloads en DeviceDoc 39702b pdf 2008 28 IEEE Std 802 3at 2009 2009 REFERENCES 209 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 Section 45 Data Memory with Extended Data Space EDS http ww1 microchip com downloads en DeviceDoc 39733a pdf 2009 Application Note for CT
16. DESIGN AND ASSEMBLY Figure 10 4 Close up of the Ethernet signals in the PCB design 2LAYER COLOR PCB 10CM X 10CM MAX with 1 0 mm PCB thickness electroless nickel immersion gold ENIG finish 100 e test and white PCB colour ITEAD provides files for checking whether the design conforms to their fabrication limitations and to generate appropriate Gerber files which makes the finishing process easy The PCB was designed with the fabrication limits in mind with adequate tolerances The only encountered issue was the very tight spacing in the PIC24 s 10 x 10 x 1 mm TQFP recommended footprint which had to be reduced in fear of manufacturing failures Figure 10 5 on the next page shows the adjusted pads which are still quite close to one another Results The results from ITEAD studio were very satisfactory The gold plating looks good there are no problems with the silk and both the 8P8C connector and cable duct milling were performed without problems The only issue which was anticipated was that the oblong 8P8C mounting holes were not made oblong This will be fixed by drilling them out with a slightly larger drill The upperside of the manufactured PCB is shown in figure 10 6 on page 74 10 6 ASSEMBLY 73 Figure 10 5 Close up of the PIC24 TQFP pad pitch 10 6 Assembly The assembly was done entirely by hand using a soldering iron During assembly the first issue with the PCB was discovered The entire row of tall co
17. Discussion 11 1 Component selection 22 2 2 2 on nn 11 2 Design flaws and improvements 11 3 Missing NFC integration 2 2 2 on nn 12 Hardware Conclusion III Software 13 Architecture 13 1 Operating system 13 2 Choosing libraries 50 50 51 52 53 56 57 61 61 62 65 66 67 67 68 68 70 71 72 73 73 74 75 76 77 79 79 80 81 83 85 87 88 89 u CONTENTS Licenses aa were sa ai a A 89 14 Development environment 91 14 1 Microchip compilers and IDE 91 Microchip software libraries 2 2 22 on nn 92 XC32 and XC16 peripheral libraries 93 14 2 Setting up a local network 2 2 on nn 93 15 File system 97 15 1 How the library works 2 2 Coon 98 Configuring FAtES u yoi a aa a 98 I O layer implementation and configuration 99 Modifications to the I O layer implementation 102 15 2 Performanc erra 2 a 44 2 aa a Anka eis 105 How the read test is performed 0 105 Results 22a Sle RR IS A ea 105 15 3 File system Structure o 107 16 Touch controller driver 109 ETC a O Maal thes 110 16 2 EP Lax06 driver 244 RRO EE KEES b EE De hee A 111 16 3 GOL interfacing 00 2 0 0000 113 17 Parallel flash driver 117 17 1 Accessing external memory using EDS 117 17 2 EPMP bypass mode o 00000000000 119 E ER 119
18. However there is a significant amount of work related to handling POST requests This work would have been much easier with a scripting language on a Linux OS The need for an external tool to parse the HTML source to generate binary resources needed by the server is also something that should be eliminated In the web UI the external resources CSS and JavaScript for plug ins and libraries are downloaded by the client whenever possible limiting the number of concurrent connections between the client and server The downside with this approach is having to rely on an Internet connection and relying on the external websites to be available throughout the lifetime of the OOD With a web server more capable of concurrent connections it would preferable to serve all resources from the OOD The libraries and frameworks used for web development were comfortable to use and came with lot of helpful documentation The results looked good on all the browsers used The web pages implemented so far demonstrates how communication between the JavaScript code and the HTTP server C code is done and should serve as guides for further development The biggest challenge remaining is finding a good interactive calendar that works well on both desktop computers and mobile touch devices and implement ways to create appointments 24 3 GUI development Microchip s graphics library provides a potent library with good GUI capabilities The biggest issue with the libr
19. ICSP pin out seen at PICkit 3 programmer 92 MAL Hle structure ato ges ar na en anna 93 FatES architecture ss 32333 aec ema Re en ne 97 Architecture of the touch driver 2 2 2 o nennen 109 Microchip graphics library architecture 22 222 200 121 Currently active GUI objects chain in a linked list 122 The Graphics Resource Converter o a 127 State machine features e 129 Architecture of Microchip s TCP IP stack o 136 Protocol dependencies in the various OSI layers 137 HTTP server state diagram 142 How adding and checking passwords is performed 152 The MPFS2 HTML converter o e e e 156 LIST OF FIGURES XV 21 1 22 1 22 2 23 1 23 2 23 3 23 4 23 5 23 6 23 7 23 8 26 1 26 2 26 3 26 4 Sequence diagram of a name query sent by the master 163 UART to RS 232 level converter adapter 000000 167 USB UART bridge ora a anna nme 168 How a request from the client is handled in the web server 170 Web UI menu structure 2 2 2 Em En 176 Interactive calendar for adding appointments 177 Availability type configuration 2 2222 nme 178 Editing colours in availability type configuration 179 Name and title configuration page in web UI 180 Network configuration page in web UI 181 Time and date configuration page in
20. MII is a standard for connecting media access control MAC to a physical layer device It supports both 10 and 100 Mbit s data rates and offers sup port for management functions It has four bit wide data paths for RX and TX two bit wide with RMIT and supports full duplex communication 38 See chapter 5 for details Enhanced parallel master port EPMP A hardware module included in some Microchip products used to interface external memories with a configurable parallel bus The data bus can be either 4 8 or 16 bits wide and up to 23 address lines can be used 41 See chapter 4 2 for details Red green blue RGB Refers to a series of buses and control lines used to drive a colour display Each colour has its own bus and the width is determined by the colour depth used For example 24 bits of colour depth has three colour buses each eight bits wide they do not need to be equal in width In 66 two major reasons for using two microcontrollers instead of one were discussed It was difficult to find one microcontroller that could drive both the display and Ethernet Even though separate hardware could be used for either 4 2 PIC24FJ256DA210 31 or both tasks another problem was fitting the libraries for graphics GUI and the TCP IP stack in the program memory with memory to spare The best solution given Microchip s selection of microcontrollers were to use two microcontrollers One would be tailored to handle graphics the other w
21. PIC24 UART debug connector JP2 Sheet 4 Miscellaneous This sheet includes the following e LEDs e Test points Sheet 5 PIC32 This sheet includes the following e PIC32MX695F512L microcontroller US with necessary circuitry e microSD card slot P1 e PIC32 ICSP connector JP3 e PIC32 UART debug connector JP4 e NFC UART connector JP5 e Buzzer Y2 Sheet 6 Ethernet This sheet includes the following e LAN8720 Ethernet transceiver U7 with necessary circuitry e TM25RS 5CNA 88 collapsible 8P8C connector J1 e Ethernet transformer FX1 with necessary circuitry Sheet 7 Nehaven display adapter This sheet contains the circuit for the board used to connect the Newhaven display to the PIC24FJ256DA210 development board through the graphics connector g RGB connector for display Plur UIN EXT NC 1 GND 1 yF 35U NC 2 CS SHDN FB i O N Il WONATAWNE 18pF 16U o GND J C termination EZRA SS UDD lig TOUCH_SCL TOUCH_SDA Touch controlller connector yoo GND TOUCH _SCL TOUCH_SDA TOUCH_INT TOUCH_RESET DISPLAY ood 4721 13 11 43 PA Sheet 1 1 6 DUCH_RESET 3 SMAJSBA Ci D2 pF 18QU DC DC converter_____________________ U4 OUTPUT VIN Jits 339 F 16U FEEDBA
22. Query Mobile framework did a good job of representing pages on the test phones used The mobile version very much felt like an application and not a website There has been no attempts to make separate versions of the content customised for smaller and larger displays so the desktop version of the web Ul seemed a bit wasteful The width and height of larger displays was not utilised This could be improved by showing more content across the width of larger displays The only major drawback found was when using SSL Although full page encryption using SSL was never intended encryption was only deemed necessary when sending passwords there was no simple way of leaving the secure page once authenticated When visiting the unencrypted page after having authenticated 26 1 WEB SERVER AND WEB UI 195 using basic web authentication the credentials were lost This should be fixed and can be done by using cookies to hold session data Browsing the web Ul using SSL was not a major problem the throughput was high enough to provide all content fast enough However the Chromium browser caused a few problems It would by default prohibit loading external non secured resources external Query and plugin resources The user would have to explicitly accept loading these resources The other browsers did not care about loading external content over unencrypted channels Chromium also seemed to not cache certain graphics causing unnecessary traffic
23. Throughput Concurrency Shortest Longest kB s transaction transaction 230 5 74 0 02 3 03 Similar tests were also performed with 20 concurrent users which is twice the number of allocated sockets see chapther 20 2 All the requests were still served proving that 10 sockets may be sufficient for serving more than 10 users at a time when serving smaller files SSL performance SSL works by encrypting data using a symmetric encryption algorithm ARC FOUR in Microchip s implementation which can be relatively fast to calculate but requires both the sender and receiver to know a pre shared secret In order to deliver this secret securely to the server the client uses an asymmetric public key key algorithm RSA in Microchip s implementation 68 sec 8 9 3 This algorithm is much computationally heavier than the symmetric algorithm used to encrypt the HTTP data but is on the other hand only used in the beginning of a transaction With this in mind there are two characteristics of SSL that should be tested e The connection start up time from the first client request packet to the finished encrypted handshake message indicating the end of the handshaking procedure The duration of this process will depend heavily on the time it takes for the PIC32 to decrypt the client key using RSA e The reduced throughput as a result of using the symmetric ARCFOUR algorithm to encrypt data to the client The previously used HTTP stress
24. While designing and producing the specialised hardware for the OOD these development boards will continue to be used in the inital phase of software development The development boards will be given a brief introduction in the following sections 3 1 PIC24FJ256DA210 development board The PIC24FJ256DA210 development board is a part of a modular series of development boards used to explore Microchip products As seen in figure 3 1 on the following page the board is relatively big and has a series of connectors and expansion ports The connectors of interest include 1 6P6C connector and 6 pin jumper for in circuit serial programming ICSP 2 Female DE9 connector for RS 232 3 Type A mini B and Micro AB universal serial bus USB connectors 4 DC connector for power TM 5 PICTail Plus a 120 pin connector used to connect other boards 6 Diplay connector a peripheral component interconnect express PCIe x4 connector used to connect display development boards A series of jumpers are used to configure the signal paths since a number of the features on the board are connected to the same pins on the microcontroller In addition to the microcontroller itself the board includes SST25VF016B 50 4C S2AF a 16 Mbit serial peripheral interface bus SPI flash 23 24 CHAPTER 3 DEVELOPMENT BOARDS gt Pictail Plus ol m 3 E SARALLEL FLASH SRAM 3 PIC24FJ256DA210 Development Board Figure 3 1 The PIC24FJ2
25. and a longer description Since the owner can only be either available or unavailable the availability types must derive from one of these base types A third special type is unknown which cannot be changed by the owner and is used by the system when the owner has not set his status No more than one availability type of each of the two kinds is strictly necessary but the possibility is there if the owner prefers to differentiate being present but busy and absent away from the building for instance Listing 19 1 on the next page shows the format of an availability The title and description come in two copies in order to support both English and an alternative languagel The calendar module does not put a limit on how long 1Bilingual support is only implemented partly in the OOD so whenever dual storage for strings is used currently only the first entry is used 131 62 63 64 65 66 67 68 69 TL 132 CHAPTER 19 CALENDAR AND AVAILABILITIES these strings can be so it is up to the owner to ensure that thev will fit on the displav ood pic32eth X calendar calendar h struct availabilitv uinti6 t baseType uinti6 t id uint32 t bgColouri uint32 t bgColour2 uint32 t textColour char title 2 1 char description 2 IPE Code listing 19 1 Availability object The owner uses the defined types of availability in appointments which contains a start and end date time Each appointment also has a t
26. avoided DISPLAY A C BOTTOM SIDE BULKY COMPONENTS Figure 11 1 The incorrect placement of the large components 11 1 Component selection Many of the decisions made are based and dependent on the choice of the architecture If an ARM processor was chosen instead of using microcontrollers the selected peripherals would most likely by different to better suit the capabilities of the much more advanced chip An ARM processor would also likely come in a BGA package requiring multiple PCB layers and it would also likely require external BGA memory chips The network solution chosen a LAN8720 with an RMIl capable microcon troller has shown to be a good choice The size and complexity of the Ether net circuit was manageable to include in the design and it worked well with a 79 80 CHAPTER 11 HARDWARE DISCUSSION two layer design It is not known whether the circuit complies with the many requirements in IEEE 802 3 but this has not been of importance when designing a prototype This should nonetheless be looked into for any further work and especially if the product should ever be considered for mass production The low power consumption drawing maximum 54 mA is also positive Compared to the transceivers tested in 66 which drew up to 200 mA this is a significant difference Together with its compact size Auto MDIX support and very good documentation and design resources the LAN8720 is recommended for other projects
27. be given throughout the thesis and summarised at the end The progress of any development after this thesis can be found at http ood 2tsa net Specification and system design Figure 2 1 The OOD mounted next to an office door Described in the most simplest terms the OOD is a small rectangular box housing a display and circuitry for a network connection and power supply 66 p 9 Figure 2 1 is a simple illustration showing how the OOD could be mounted next to a door The size of the display should be small enough to not resemble a 9 10 CHAPTER 2 SPECIFICATION AND SYSTEM DESIGN monitor but large enough so that it can show text visible from a few metres away Its housing should be not much larger than the display itself and most importantly as slim as possible given that it s going to be mounted on a wall It should be easy to install and require as little cabling as possible 2 1 Areas of application Remote control User interface UI ps ii 2 n AWAY 5 Q A a O Re Card reader Figure 2 2 The out of office display OOD s interactions Employee list 00D Figure 2 2 from 66 illustrates how the out of office display OOD is designed to interact with its environment It consists of a local interface a touch display along with a near field communication NFC reader and a remote interface the web server The web interface built on common protocols can easily b
28. by the compiler The noload attribute tells the compiler that initial values should not be loaded Any access to the address flash with an offset will access the corresponding address in the flash IC ood pic24gfx X m29w320FlashDriver c static __eds__ uint16_t __attribute__ eds noload address M29 EPMP CS BASE ADDRESS flash Code listing 17 1 Defining an EDS address to external EPMP memorv Reading from EPMP memorv is done bv reading the requested address The returned value is rubbish but the dummy read is necessary When the EPMP 117 118 CHAPTER 17 PARALLEL FLASH DRIVER ood pic24gfx X m29w320FlashDriver c 217 static void rawWrite uint32_t address uint16_t data 218 fe 219 Wait for any previous write actions to complete 220 while PMCON2bits BUSY 221 222 volatile __eds__ uint16_t amp flash address data 223 224 225 static uint16 t rawRead uint32 t address 226 Do a dummy read of the address The actual data has to be 227 retrieved 228 x using the PMDIN buffer register x 229 void volatile eds uinti6 t amp flash address 2 i Wait till read has been performed and data is ready in EPMP in 231 buffer 232 233 while PMCON2bits BUSY 234 235 Return data from EPMP in buffer 236 return PMDIN1 237 Code listing 17 2 Accessing external EPMP memory using EDS module is done accessing the external memory the returned val
29. command const char command void callback const char arg E Code listing 22 4 UART command definition callbacks and if there is a match the callback is executed with the remaining characters after the first space as its argument 22 4 NFC reader There has not been enough time to write code to communicate with the NFC reader However it should not be a major task to implement a driver for PN532 and a lightweight library libnfc 7 LGPL and Adafruit s NFCShield Arduino library 5 BSD are examples of two NFC libraries with PN532 support that can serve as inspiration Web interface Giving the owner of the OOD the power of remote controlling the display is the most important feature of the device Although the local display UI gives the owner ways of changing his status on the spot any complicated configuration is designed to be performed only by using the web interface A web interface can be displayed on a much larger screen or a screen with greater pixel density and it can utilise input methods as a keyboard and a mouse It also has the benefit of not requiring the user to stand in a corridor to do lengthy work on a wall mounted touch screen In addition to being a full featured control panel for the owner the web interface is also designed to display the same information as the display If there are concerns about revealing too much information about the owner s appointments and whereabouts to the world wi
30. distinguish the LAN8720 from other units on a RMII bus e Mode RXD0 MODE0 RXD1 MODEI and CRS DV MODE pins used to set mode half full duplex etc or auto negotiation 40 CHAPTER 5 ETHERNET e Enable disable internal 1 2 V regulator LED1 REGOFF pin e Reference clock or interrupt selection LED2 nINTSEL pin which is used to choose whether the NINT REFCLKO pin should be used to output a reference clock or an interrupt signal These settings are strapped high by tying the pin to VDD except for REGOFF and nINTSEL which must be tied to the analog power see next section 46 p 31 The mode and address pins doubles as some of the RMII signal lines and can be configured by the PIC32 The internal regulator is used so the REGOFF pin does not need to be tied to ground but in order to output the reference clock on NINT REFCLKO nINTSEL needs to be tied to ground A 10 kQ pull down resistor is used for this GND UDDA 16U UDDCR UDD ees cas en Tk 1 p GND GND LED1 REGOFF YDD L3 UDDA VDDC LED2 NINTSEL Eon l E 16U 3 ie 3 a ezz less u a t 16U ja C29 C38 c 9 470pF a ND GND GND 5 Y S a ale m GND H N Figure 5 2 LAN8720 power circuit diagram Power The LAN8720 needs both digital and analog power The digital power is provided by the main 3 3 V supply on the board and is fed to the chip VDDIO An internal voltage regulator provides 1 2 V which requires two capacitors on the VDDCR pin T
31. file is protected In the next state PROCESS GET any arguments provided in the GET request are parsed A user provided function HTTPExecuteGet is called to handle these arguments If the request was POST instead of GET the next state PROCESS POST calls a user provided function HTTPExecutePost to search for key value pairs in the data After the request is processed the web server prepares to send 142 CHAPTER 20 TCP IP STACK PARSE REQUEST File found PARSE HEADERS headers parsed AUTHENTICATE bob asuodsa PUNOJ jou ayy if any arguments if no arguments ET Tre PROCESS GET arguments parsed and callbacks done more data needed and data available yield 0v asuodsai pasn 08 od pue p nb ISS LOv asuodsai pasiloyine ou PROCESS POST Figure 20 3 HTTP server state diagram 20 5 HTTP SERVER 143 3 nm U o 5 u m ll u o o ejep JJOW ou pue papaau ejep siow auop sxdeq e gt pue pasied sjuaunbe SERVE HEADERS headers served and cookies to serve vIv asuodsai MOLLISAO SERVE COOKIES 9A1J9S 0 S9I009 OU pue panas Siapeay cookies served 1SOd i 1sanba pue 139 i Jsonbol SERVE BODY timeout occurred tie Sant DISCONNECT Figure 20 3 HTTP server state diagram continued 144 CHAPTER 20 TCP IP STACK data In SERVE HEADERS information about the content Content Type encoding and cache is sent as hea
32. for a local network but it will struggle hosting web pages for many users In the case of the intended use for OOD the solution is good enough as long as a public interface is not used The graphics solutions provided by Microchip appear to be feature rich and contain everything needed to make GUls for an embedded system It is slightly difficult to use but this may change as Microchip develops GUI designer tools with intuitive editors and code generation features 205 206 CHAPTER 28 CONCLUSION The hardware prototype made has a few minor flaws but is otherwise fully capable of housing the features of the OOD including Ethernet PoE abundant memory and a large colour display with capacitive touch The OOD may by on the very edge of being too complex to be implemented on microcontrollers This thesis proves that it is possible to implement TCP IP with 2048 bits SSL along with powerful GUI but it takes a lot of effort and may just not be worth the time and trouble With few reasons not to use a platform with an embedded Linux it should be considered for further development to use an architecture which allows more focus on the application software rather than low level details References 32 bit PIC Microcontrollers http www microchip com pagehandler en us family 32bit architecture html Accessed Jun 23rd 2013 Apache License Version 2 0 https www apache org licenses LICENSE 2 0 html Accessed Jun 29th 201
33. for hosting iii iv web sites for more than a handful of users simultaneously SSL with 2048 bit keys is possible although it will add a three second delay to any HTTPS connection due to the computationally heavy RSA decryption The throughput using HTTPS is measured at 317 kB s using 128 bits ARCFOUR This works well to secure an authentica tion step but the throughput is not optimal for securing all HTTP traffic The results prove that the selected microcontrollers are capable of running a GUI and a secure web server but the performance is only good enough for undemanding applications It would be preferable to have a better performing web server The system may be too complex for an microcontroller approach and it should be considered for further work to look into solutions using an embedded Linux Sammendrag I enkelte arbeidsmiljger er det vanlig opps ke hverandre p kontoret uten m tte ha en avtale I slike milj er kan det v re frustrerende nar den du pr ver fa tak i ikke er tilstede og det er ingen infor masjon om hvorfor vedkommende er borte og hvor lenge Dette er ikke en uvanlig situasjon p universitet hvor studenter stadig fors ker f tak i veiledere og professorer men ofte blir m tt med en l st d r Det er akkurat slike opplevelser som er motivasjonen bak l sningen presentert i denne oppgaven L sningen er i form av et apparat med en fargeber ringsskjerm og nettverkstilkobling som kan fje
34. he disappears even for short errands This scenario is not limited to universities In office environments where it is common to seek one another without having an appointment it can be frustrating having to frequently visit empty offices hoping to get hold of someone The main motivation for developing an electronic out of office system does however come from an academic environment From the author s personal experience it can be very difficult to get hold of certain academic employees Sometimes the best way to get hold of an employee at the department is to meet up at their office When the door is locked and coworkers can assure you that the person concerned is present somewhere on the premises the author has missed a way to be informed more accurately about their absence In the case the person in question is absent for hours perhaps in a meeting unable to answer calls being informed about the absence would eliminate the need to constantly meet up at the door to see if the employee is back Although the presented problem may seem piffling to some the suggested solution may prove to be a great aid in improving communication between workers in an office environment Having a display next to the door can also eliminate the need for a name sign and a portrait where needed making the process of updating and replacing these easy 1 1 Background In Preliminary Design of an Out of Office Information System 66 the out of office proble
35. it could be given back to the community of MAL users and be useful The code is not tested with MDD and MPFS however and it is not known whether the support for these file systems are intact Looking back on the time spent to keep this multi file system support the decision is regretted Time could have been saved and used on more useful tasks and the resulting source code would be much more readable The stack comes with good documentation and is relatively easy to use despite its size and complexity On the other hand a lot of the configuration settings are scarcely documented and Microchip expects the developer to get an understanding of the settings but looking at the demo code The source code is also at times difficult to understand due to non descriptive variable names and variable re use For example in the HTTP server source HT TP2_MDD c 2701 lines long the variables lenA lenB dummyPtr ptr tempPtr dummyCntr and 185 186 CHAPTER 24 SOFTWARE DISCUSSION entr are used extensively Along with a number of global variables and extremely long functions this made it tricky to understand and edit the source code 24 2 Web development Using an embedded web server makes it challenging to make dynamic and interactive web content Methods of utilising the existing features of the web server along with a few custom extensions have been demonstrated and shown that it is indeed possible to make a web UI with a simple HTTP server
36. lack of any exisiting products that could be purchased and used Making the hardware is also a great opportunity to gain more knowledge in PCB design which will be much appreciated 10 1 Software tools used It has been challenging to find electronic design automation ECAD tools The only professional tool available at ITK is Orcad which would be difficult to master in the short available time given and was considered as a last resort Altium Designer was considered the best software based on feedback from fellow students but it was not possible to obtain a license for the software The open source ECAD suite gEDA with programs such as Gschem and PCB was also considered but seemed cumbersome to use and had very few components footprints available The choice fell on Eagle which is a popular ECAD tool among hobbyists due to availability of a freeware license With a freeware license the software may only be used for non commercial or educational applications the board area is limited to 100 x 80 mm and no more than two layers can be used This pose no immediate problem for the project which is designed for two layers and can most likely fit within the restricted area If the OOD ever were to make it as a commercial product a commercial license of Eagle can be purchased or given many changes made from scratch using a different program Eagle excels in three areas e It is very easy to start using yet has a number of advanced feat
37. mcuc_doSPIWork which transmits receives data according to an internal state in the module A number of other functions listed in listing 21 1 on page 164 are implemented differently in the two microcontrollers These functions are called from mcuc doSPIWork The core of the inter microcontroller is implemented and tested leaving a foundation for further development A weakness with with the protocol or any SPI protocol is that the contents of the SPI buffer is retrieved by the master regardless of whether the slave has updated it or not If a master does two reads without the slave having updated its buffer the master will receive the last packet it sent which can be perfectly valid data and hard to detect as an error The 163 Quer name Q NAME 0 amp STATUS STATUS ERROR not ready STATUS R NAME 3 STATUS Figure 21 1 Sequence diagram of a name query sent by the master 25 26 27 28 29 30 SE 164 CHAPTER 21 INTER MICROCONTROLLER COMMUNICATION ood mcuC mcuc h union packet mcuc_makeStatusPacket int mcuc_handleReceivedPacket int packetType uint16_t packetData uint32_t packetLen void mcuc_handleError struct errorInfo error void mcuc_handleStatus union packet packet Code listing 21 1 Microcontroller specific functions in mcuC the name of the inter controller communication library module will trigger an error if the buffer overflows but i
38. one function is used per I O pin a table is made Appendix B on page 217 includes a table listing all the pins present on the PIC24FJ256DA210 their functions the functions used and for what purpose The table is sorted and colour coded based on the purpose of the pins and functions used Then columns Alt function and Moveable indicate whether the function used on the given pin can be moved Some of the EPMP lines can be used on alternative pins as seen in the table but ultimately only the result presented in the table will work due to collisions Re mappable pins which can be used for UART and SPI are named RPxx or RPlzx 34 CHAPTER 4 MICROCONTROLLERS Necessary connections The absolute minimum of connections for running the PIC24 are illustrated in figure 4 3 A crystal is used to provide a stable oscillator The crystal s frequency is 8 MHz and is used together with a phase locked loop PLL to achieve the highest system clock of 32 MHz 34 p 151 The decoupling capacitors and other resistors in figure 4 3 are picked based on the shown recommendations A compact right angled pin header with 1 27 mm pitch is used to connect an ICSP programmer to the microcontroller See sheet 3 in appendix C for the full circuit diagram c20 VDD Key all values are recommendations TA C1 through C6 0 1 F 20V ceramic RI R2 S gt ni m C7 10 F 6 3V or greater tantalum or ceramic EAN mar EN DIS VREG Rt 10 kO VCAP VD
39. option to edit the main language A second edit field for all the billingual strings needs to be added to complete the support lhttp dev jtsage com jQM DateBox Creative Common Attribution License 3 0 Software Discussion The software put together so far provides a good foundation for further development and finishing of the OOD Networking and TCP IP is in place all necessary hardware drivers are made and tested and the framework for storing and retrieving appointment data to and from file is completed Necessary amendments has also been made for the graphics library but no GUI menus has been made The software will be tested on the OOD hardware in chapter 26 and the system as a whole will be discussed and evaluated in chapter 27 In this chapter the libraries and development process will be discussed 24 1 TCP IP stack The TCP IP stack was chosen because it was tailored for the microcontroller used and because it also provided a free SSL implementation As the results later will show the stack performs well seemingly only held back by the read speed limitations of the file system SD card Modifying the stack s HTTP server to work with FatFS took a lot of time to get everything work correctly The idea was to keep the software s existing support for the other file systems MPFS and MDD by continue using a lot of preprocessor conditionals This was not directly useful for the project in any way but it was done in hope that
40. order to have a chance of storing a portrait in memory for fast loading The chosen SRAM was the cheapest option from Farnell at NOK 57 76 per unit NOK 37 75 per 100 units The memory is 16 bit accessible for maximum throughput It comes in a 44 pin thin small outline package type II TSOP II which is easy to solder Figure 7 6 on page 56 shows the SRAM connected to the PIC24 with EPMP lines along with power connections and decoupling capacitors 2 522240 510 kB 54 CHAPTER 7 GRAPHICS AND DISPLAY q E i b PCB bottom layer Figure 7 4 Display PCIe x4 adapter with backlight LED driver 7 3 SRAM 55 a Underside b Upper side Figure 7 5 Milled PCB with components and display fitted 56 CHAPTER 7 GRAPHICS AND DISPLAY PMAQ PMDO PMAL PMD1 PMA2 PMD2 PMA3 PMD3 PMA4 PMD4 PMA5 PMD5 PMAG6 PMD6 PMAZ PMD PMA8 PMD8 PMAS PMD9 PMA1B PMD1 PMA11 PMD11 PMA12 PMD12 PMAL3 PMD13 PMA14 PMD14 PMA15 PMD15 PMA16 PMCS1 UDD PMA17 PMWR PMA18 PMRD GND GND GND 5 1 pF N y Lp O 1 ce GND GND Figure 7 6 SRAM circuit diagram 7 4 Double buffering Double buffering has been mentioned several times but not yet given an explanation Double buffering is a technique that avoids some of the problems caused by updating the frame buffer directly For short operations changes to the frame buffer goes unnoticed by the user Time consuming operations which for i
41. p 7 Delay User reaction 0 100 ms Instant 100 300 ms Feels sluggish 300 1000 ms Machine is working pls Mental context switch gt 10s T ll come back later 23 3 Selecting application framework The two main requirements for the web Ul listed in the specification are to that it should be possible to configure all the major settings and that the interface should work just as well on mobile devices as on desktop computers An increasing portion of the web traffic world wide comes from mobile devices 55 so it is important to design an interface that works on smaller displays and with touch input Making a well working interface for mobile phones also increases the chances for the owner to update his availability as often as possible He is not dependent on a desktop computer to configure the OOD and a well designed UI will let him do changes in a short amount of time With the extensive selection of JavaScript aided libraries available for implementing interactive responsive and mobile ready web sites there is absolutely no need to reinvent the wheel or make the UI from scratch It is however a bit overwhelming to look for libraries with the extreme selection of many good candidates Among the considered libraries and application frameworks are e Query UI http jqueryui com e Bootstrap http twitter github com bootstrap 23 4 DEVELOPMENT ENVIRONMENT 173 e MooTools http mootools net e
42. phones in portrait mode tablets or desktops but the table will refiow into a different representation in order to fit on small displays ilabl Select colour vaile vail Background 1 METEO vaile one 2 Text r Please disturb vail FFFFFF gt ilable r a ee vailable e Caribbean no calls use e ma ew Figure 23 5 Editing colours in availability type configuration When clicking on the colour gradients the owner is presented with an intuitive way of settings colours with the help of a colour selector see figure 23 5 Three colours are used one for text and two that will make up a gradient A gradient is chosen rather than a solid colour because it looks nicer and there is already support for drawing gradients in the display GUI The plug in chosen for the colour picker is JSColor Among the many colour pickers available this library appealed the most with its simplicity and small code size 30 kB Table 23 2 Format of data returned from availability query functions ID type bg colour 1 bg colour 2 text colour title description Editing and deleting availabilities is done by posting queries to con fig availTypePOST html The query format is documented in the C source Inttp jscolor com LGPL license 2The field delimiter used is f and the separator between full elements is Ann 180 CHAPTER 23 WE
43. serves the data stored in step 3 and invalidates it to ensure that subsequent GET requests to the same URL returns an error code The implementation is cumbersome but necessary It would be more efficient to serve the data directly in the POST processor callback but this is unfortunately not possible as explained in chapter 20 5 Data is usually delivered to the client in a compact serialised format rather than JavaScript object notation JSON This relieves the microcontroller of having to comply with the formatting rules of JSON it keeps the data transmitted compact and it can utilise the power of JavaScript in the client browser to interpret the result The downside with this approach is that makes it harder to use the backend with its POST features as an API since clients need to convert the result instead of using a popular and standardised serialisation format as JSON 19 This can be improved by implementing JSON formatting support in the microcontroller but it has not been prioritised 23 2 Frontend When designing the frotend the limitations affecting the backend as well as other limitations need to be taken into consideration Since the dynamic variable functionality of the web server is not truly dynamic the callbacks are set up at compile time any request for data need to be performed as POST requests For a better used experience these requests should be performed asynchronously Among other considerations that are not bac
44. setting colour clipping regions and copying rectangular areas efficiently using the GPU The driver is initialised with ResetDevice but it is not necessary to call this function if any of the higher layers are used If double buffering is used in either the primitive layer or driver layers the double buffering must be handled by the user This is done by using the function InvalidateRectangle to clear areas of the screen and UpdateDisplayNow to swap draw and frame buffers See chapter 7 4 for how double buffering works The primitive drawing functions are straightforward However it is important to note that they are either blocking or non blocking depending on the setting USE NONBLOCKING CONFIG in GraphicsConfig h GOL In order to use the graphics object layer it must be enabled in the graphics configuration and the necessary widgets must be include by their appropriate defines All necessary initialisation is performed by calling GOLInit A widget is created on the heap using its create method For example the following creates a rounded corner button with id 2 with the text OK in the upper left corner of the display BtnCreate 2 0 0 100 50 5 BTN_DRAW NULL OK NULL Parameter 2 5 are the coordinates which also defines the size 5 is the roundness radius BTN DRAW says that the button should be drawn immediately the NULL means that no bitmap should be used and the last NULL indicates that the default
45. terminating null byte See appendix A for how the various configuration loading saving routines are implemented 22 2 Tick module The TCP IP stack includes a tick module which provides methods for measuring relative time PIC24 does not have such a module and is therefore given its own simple tick module implementation The PIC24 tick module is not intended to be used for accurate measurements but for providing non blocking delays It also comes with a means of executing callbacks after a given delay This makes it possible to postpone execution of functions or have functions called repeatedly with a given interval Listing 22 3 shows the function for adding callbacks together with an example of how it is used to blink a LED a number of times An interrupt routine takes care of updating the module s current tick and the function tickTimer_handleCallbacks checks all the registered callbacks timestamps and calls the callbacks if they have expired This function must be called repeatedly from main The tick module in PIC32 provided by the int tickTimer_addCallback void callback void arg void arg int intervalMSecs int repeats tickTimer_addCallback amp reverseUSR2LEDState NULL rateMS numFlashes iL Ng void tickTimer_handleCallbacks Code listing 22 3 The tick timer module s callback functionality 22 3 UART AND DEBUGGING 167 TCP IP stack does not have the callback functionality so a modif
46. testing tools do not distinguish the SSL handshake duration from the overall response time In order to measure the time it takes to perform the RSA calculations Wireshark will be used to overview the handshake procedure and find the delay The tests were performed with the Chromium Iceweasel and Android browser see chapter 23 4 for versions used A very consistent delay of 3 05 seconds was observed over tens of tests with all browsers The delay was measured as the time passed from the client SYN packet to the server encrypted handshake message 198 CHAPTER 26 TESTING AND RESULTS dal L L sage ult BABBBIIDLEN 45 3 075627000 SSLv3 Encrypted Handshake Message Figure 26 1 SSL handshake duration Wireshark screenshot only relevant packets shown as illustrated in figure 26 1 Since the SSL module supports saving session data any subsequent HTTPS connection will take drastically less time down to a negligible delay of a few ms Figure 26 2 SSL handshake duration with saved session Wireshark screenshot only relevant packets shown Figure 26 3 on the facing page shows the server replying with the same session ID as the client which makes it possible to skip the time consuming part of the handshake process An interesting observation made during the tests is the great variation in delay when clients connected with saved session data The delay varied from anywhere from seconds to two milliseconds decreasing for every c
47. the largest Ethernet frame is 1522 octets but since the value has to be a multiple of 16 bytes the buffer size is set to 1536 These settings are set in TCPIPConfig h The socket buffers can be customised per application based on different RX TX and buffer size needs Since the only TCP application is the HTTP server only the web server sockets need to be configured Listing 20 7 on the facing page shows how the sockets must be configured and allocated as a global struct array in TCPIPConfig h The line is duplicated 9 times for the 10 sockets allocated TCP PIC RAM indicates that the RAM used is internal microcontroller RAM which is the only option in this application The RX and TX buffers are both set to 1500 but the RX buffers can be down adjusted without much noticeable loss in performance if there should be a shortage of RAM It is the rate of which data can be sent from the server to the client TX that is most noticeable for the user lAn Ethernet frame with a full payload of 1500 octets also contains the following fields destination address 6 source address 6 length type 2 frame check sequence 4 and possibly a tag 4 24 p 34 49 155 126 127 128 129 130 131 132 133 20 6 SSL 155 ood pic32eth X TCPIPConfig h ROM struct BYTE vSocketPurpose BYTE vMemoryMedium WORD wTXBufferSize WORD wRXBufferSize TCPSocketInitializer TCP_PURPOSE_HTTP_SERVER TCP_PIC_RAM HTTP_SOCK
48. throughput and how well the server handles multiple users Robustness and error handling Although there are tools especially designed for testing web sites a much simpler approach is taken by just repeatedly using various functions in the Ul in a random fashion The following behaviours were studied e Do the forms handle expected input correctly e Do the forms correctly handle incorrect input is the user notified of the error and does the server reject the data e Do any of the pages or functions show unexpected behaviour when called numerous times in a row e Can the user cause any trouble by disabling JavaScript or attempting to interact directly with the API which should be possible The tests revealed that the web UI pages were robust no errors or unexpected behaviour was found It was noted that the feedback given to the user when 193 194 CHAPTER 26 TESTING AND RESULTS providing incorrect data in the forms could be improved The forms distinguish between empty too long for the server s parsing buffers and incorrect input but the user is not told which field that caused the error This is no major problem but in cases where many of the inputs are similar the user should be given information about which field contains the incorrect input This could be done by highlighting the incorrect field with CSS effects helping the user to find his mistake Since care has been taken when writing the backend to handle inc
49. to be used is by using states to refer to menu pages Entry actions will create all necessary widgets exit actions will destroy them GOL messages will be handled in transitions to change states as the user clicks on buttons in menus Calendar and availabilities The calendar module holds all the data on appointments and availabilities set by the owner It as accessed by both the web UI and the display and the module is implemented in the PIC32 Despite its name the calendar module does not contain any calendar data like weekday or leap year information For the current 00D implementation this it not needed because the JavaScript libraries used in the web Ul comes with all this data and the display will not yet provide detailed calendar views Later improvements may include calendar views on the display for which such data may be needed Then the module needs to be upgraded with date formulas The calendar module provides methods for loading and saving appointments and availability types to and from files on the file system The following section will introduce the format used for this data The HTTP server backend will use these functions to send ASCII serialised objects to the JavaScript frontend in the web UI Similarly objects will be serialised for transport over SPI when requested by the PIC24 19 1 Appointment and availability format The owner is allowed to define his own types of availability which he may assign a colour name
50. to drive all of the chosen components would make an suitable power supply circuitry for the OOD Although the prototype from 66 was designed with physical limitations in mind a second look on the components should be taken in hope to find even more compact parts Non volatile memory Persistent memory is needed to store larger quantities of static data principally web sites pictures for the owner s portrait and fonts and graphics for the display GUI Storage is also needed for configuration and settings as well as calendar data for availability statuses The requirements for the non volatile memory are Capacity The memory need to be large enough to contain all of the above mentioned with a good margin 1A powered device PD is the part of a power over Ethernet PoE system that accepts power from power sourcing equipment PSE 16 CHAPTER 2 SPECIFICATION AND SYSTEM DESIGN Fast read access The display needs to retrieve graphics and fonts fast enough in order to avoid causing noticeable delay for the user The web server also needs fast access to web pages fast enough to provide a responsive interface and good browsing experience Development friendly This requirement is weighted heavy due to the lack of time and need for an efficient way to manipulate the data during development Using a removable memory card as a main storage medium would make it very easy to manipulate data during development Write access The sy
51. web Ul 182 SSL handshake duration Wireshark screenshot 198 SSL handshake duration with saved session 198 Client hello and server hello packets with same session ID 199 GUI main page mock up on development board 200 5 1 RMII signals 6 1 microSD card pin out 7 1 LED driver BOM List of Tables 8 1 Maximum operating currents per device 15 1 FatFS configuration 15 2 Required user implemented functions in FatFS 15 3 The file system structure seen from the root directory 16 1 Excerpt of FT5x06 operating mode register Map 20 1 Files needed from the TOPP stack ee na 222 a E 20 2 Format of FileRerd bin iin pe ee e a a a a A e ee a i i a 20 3 Format of DynRerd bin Lee 20 4 HTTP_IO_RESULT return values 21 1 Inter microcontroller communication packet format 23 1 User reactions to various web page delays 23 2 Format of data returned from availability query functions 26 1 Multiple connection throughput results o 26 2 10 concurrent users 10 repetitions using a 10 kB file A 1 Source code contents 38 45 52 63 99 100 108 113 137 147 147 149 161 172 179 196 197 215 xvii List of Acronyms ACL access control list AJAX asynchronous JavaScript and XML API application programming interface
52. 19 C20 C21 C26 C28 C37 C44 19 1uF C EUCO402 C45 C46 C47 C48 C49 1833861 1 330uF 16V CPOL EUG C9 2102435 1 Schottky 30V 0 2W DIODESOD D1 1843742 1 SMAJ58A DIODE DO214AC D2 1886349 1 DNP DIODE DO214AC D3 2 B260 DIODESMB D4 D5 1858612 1 TG110 E055N5 TG110 E055N5 FX1 1644274 1 TM25RS 5CNA 88 TM25RS 5CNA 88 J1 1 PIC32 ICSP M051 27MM 90 JP1 1099572 1PIC24 DEBUG UART M031 27MM 90 JP2 1 PIC24 ICSP M051 27MM 90 JP3 1 PIC32_DEBUG_UART M031 27MM 90 JP4 1 NFC UART PINHD 1X4 90 JP5 115uH WE TPC 744028001 2811 2813 L1 2082543 1 DR125 331 R DR125 L2 1704118 1 500mA BML15HB121SN1 L3 1515758 1 MICROSD_SPI_MODE0893 MICROSD SPI MODEO893 P1 2060731 2 MOSFET NCHANNELSMD MOSFET NCHANNELSMD Q1 Q2 1471049 10 50 R EU RO603 R1 1506135 Bill of materials Qty Value Device Parts Fanrell part no 1DNP R EU RO402 R11 24 7kQ R EU RO402 R12 R13 9232842 1DNP R EU_R0805 R14 2008388 8 3300 R EU RO402 R15 R16 R18 R20 R21 R22 R23 R30 2059219 11k R EU RO402 R19 1174154 124 9k0 R EU RO603 R2 1469785 5100 R EU RO402 R24 R25 R26 R31 R35 9232524 112 1k 1 R EU RO402 R28 1652747 1330 R EU RO402 R29 1174144 5 10kQ R EU RO402 R3 R17 R27 R33 R4O 1174160 1 1 5kQ R EU RO402 R32 1174155 110k 1 10W R EU RO402 R34 2059239 4 49 9k0 1 R EU RO402 R36 R37 R38 R41 1469720 4750 R EU RO402 R39 R42 R44 R45 1458822 17 68kQ R EU RO402 R4 2140849 100 R EU_R1210 R43 1653183 14700 R EU RO402 R5 2140742 122 1kQ R EU RO603 R6 2059437 122 10 R EU RO
53. 3 Capacitive Touch with Near Field Communication http www cirque com technologies glidepointnfc aspx FatFs Module Application Note http elm chan org fsw ff en appnote html Accessed May 26th 2013 GitHub Adafruit NFCShield I2C https github com adafruit Adafruit_NFCShield_12C Accessed Jul 5th 2013 How to Start Using SD Standard in Your Product https www sdcard org developers howto Accessed Dec 19th 2012 libnfc org Public platform independent Near Field COmmunication NFC library http www libnfc org documentation introduction Accessed Dec 20th 2012 Microchip PIC24F Peripheral Library Help Part of XC16 compiler documentation MIFARE Standards http mifare net overview mifare standards PIC24F Low Power 16 bit MCUs http www microchip com pagehandler en us family 16bit architecture pic24f html Accessed Jun 23rd 2013 PN5321A3HN Near Field Communication NFC controller http www nxp com products interface and connectivitv nfc devices PN5321A3HN html overview 207 208 REFERENCES 12 pool ntp org How do I setup NTP to use the pool http www pool ntp org en use html 13 SD Specifications Part 1 Physical Layer Simplified Specification Ver sion 3 01 http www sdcard org downloads pls simplified specs Part 1 Phvsical Laver Simplified Specification Ver 3 01 Final 100518 pdf 14 TCPIP Stack Performance Part of the Microchip Libraries for
54. 4 comes in numerous packages both TQFP and ball grid array BGA Although it would likely be possible to solder BGA packages using equipment on campus routing the signals would require numerous layers As mention in chapter 1 1 a two layer PCB is the goal for this project and for these reasons the 100 lead 12x12x1 mm TQFP package will be used in the design The small lead width 0 18 mm and pitch 0 40 mm 34 p 393 is very small however and may put the fabrication house to the test It is the integrated graphics controller that makes the PIC24 a good candidate Another very useful feature is the possibility to map peripheral functions to I O pins Being able to choose which pins that should be used for UART and SPI gives more freedom when routing the PCB 32 CHAPTER 4 MICROCONTROLLERS PIC24 core A Instruction decode Working 24 bit instruction length register Program memory array 16 x 16 bit Program counter bits 256 kB Shadow register HW array Signed 16 bit x 16 bit Interrupt Integrated 10 bit USB pnd P graphics CRC comm ADS CTMU ore controller 11 5 16 bit 2 L 9 Input capture RTCC DS BOR l Watchdog Deep meee Figure 4 2 PIC24F architecture 10 EPMP The EPMP module enables the PIC24 to communicate with other devices using parallel buses The external address space can be mapped to internal memory addresses using the extended data space EDS interfa
55. 52 CHAPTER 7 GRAPHICS AND DISPLAY Table 7 1 LED driver BOM Symbol Type Value Description Ul Boost controller RI Resistor 0603 0 5 Q R2 Resistor 0603 10 kQ R3 Resistor 0603 7 68 kQ R4 Resistor 0603 470 Q Cl Capacitor 2312 10 pF 16 V Tantalum C2 Capacitor 2312 10 pF 35 V Tantalum Ll Inductor 2813 15 pH 0 42 A D1 Diode schottky SOD 323 30 V 0 2 W Q1 Transistor N MOSFET SSOT 3 60 V 1 7 A Fast switching GD 15 11 Red 8 0 GD 10 5 Green 8 0 des 7 3 GD 4 Blue 2 0 HSYNC HSYNC Digital power backlight and touch signal lines are not shown Figure 7 3 Signal lines between the display and the PIC24 microcontroller PCB design Sheet seven in appendix C shows the complete circuit diagram for the display adapter with the LED driver I C termination and connectors A two layer PCB was made using the milling machine at ITK s workshop Figure 7 4 on page 54 shows the top and bottom layer of the PCB JP1 is a jumper that pulls up the 7 3 SRAM 53 PC clock and data lines to 3 3 V R5 and R6 are the pull up resistors initially chosen with a resistance of 4 7 kQ which will prove to give acceptable I C signals at both 100 kHz and 400 kHz JP2 provides pins for 3 3 V ground FC signal lines and an interrupt and a wake signal from the FT5x06 touch controller Figure 7 5 on page 55 shows the milled PCB with vias inserted components soldered and display fitte
56. 53 93 both well equipped with development aids and tools It will be a goal to support these three browsers when developing pages However when the older Android browser holds back a major non critical feature due to its partial lack of modern HTML5 support it will be ignored in favour of making a better user experience for the remaining platforms 174 CHAPTER 23 WEB INTERFACE 23 5 Outline of a page with Query Mobile jQuery Mobile uses asynchronous JavaScript and XML AJAX to load pages Instead of having the web page torn down and displaying the new page being built element by element on the screen jQuery Mobile loads the new page in the background and goes to the new web page only when it is fully loaded This is shown to be a very useful feature on an embedded web server since it makes it far less annoying even waiting up to numerous seconds for a new page to load The waiting notification subtle animations and page transitions may seem to make it more comfortable to browse in an application suffering from a slow server When Query Mobile loads pages from links or JavaScript which will be handled with AJAX it looks for div elements with the custom data attribute role with the value page This has some implications Normally scripts are loaded in the HTML head or possibly at the end of the file before the closing body tag This will not work with Query Mobile since only the contents within the aforementioned d
57. 56DA210 development board SST39LF400A 55 4C EKE a 512 kB parallel flash with 55 ns access time IS61LV25616AL a 512 kB parallel static random access memory SRAM with 10 ns access time Together with a display this hardware is well suited to develop graphical applications 3 2 Graphics Display PowerTip 4 3 480x272 Board This board includes a PowerTip PH480272T_005_111Q 480x272 TFT LCD display with a resistive touch overlay It is glued on top of a PCB that routes the display signals from the flat cable on the display to a male PCIe x4 graphics connector The board also includes a LED driver that runs the display backlight 3 3 PIC32MX695F512L board This is not really a development board but a PCB with room for a 100 pin 12x12x1 mm thin quad flat package TQFP integrated circuit IC and has 3 3 PIC32MX695F512L BOARD 25 Figure 3 3 The PIC32 development board headers routed too all the pins of the attached IC In addition it comes with room for surface mounted crystals a reset button and all the necessary capacitors to complete a minimum circuit for a PIC24 PIC32 microcontroller see chapter 4 2 This board is used to house a PIC32MX695F512L 26 CHAPTER 3 DEVELOPMENT BOARDS 3 4 ENC28J60 board Figure 3 4 ENC28J60 development board This small board houses an ENC28J60 a popular Ethernet transceiver that can be interfaced using SPI The ENC28J60 is not intended to be used in the OOD but it will be used during in
58. 6 bit SRAM x define GFX_EPMP_CS1_MEMORY_SIZE 0x100000u1 define USE GFX EPMP EPMP timing and polarity configuration fdefine EPMPCS1_CS_POLARITY GFX_ACTIVE_LOW define EPMPCS1_WR_POLARITY GFX_ACTIVE_LOW define EPMPCS1_RD_POLARITY GFX_ACTIVE_LOW define EPMPCS1_BE_POLARITY GFX_ACTIVE_LOW define EPMPCS1_ACCESS_TIME 55 Code listing 18 1 SRAM frame buffer configuration in HardwareProfile h 57 58 59 60 62 63 64 65 66 67 68 69 70 72 73 74 75 76 TT 78 124 CHAPTER 18 GRAPHICS LIBRARY Listing 18 1 on the previous page displays the frame buffer SRAM configura tion in HardwareProfile h Most of the configuration is self explanatory defining the frame buffer access time capacity and signal line polarity The start address 0x20000 is the start address of the EDS address space and will be subtracted from the frame buffer start address resulting in 0 GFX GCLK DIVIDER is used to divide the internal 96 MHz PLL clock source in the microcontroller 34 p 147 to match the display clock cycle 9 15 MHz 67 p 11 ood pic24gfx X HardwareProfile h define GFX_DISPLAYENABLE ENABLE define GFX_HSYNC_ENABLE define GFX_VSYNC_ENABLE define GFX_DISPLAYPOWER_ENABLE define GFX_CLOCK_POLARITY GFX_ACTIVE_LOW define GFX_DISPLAYENABLE POLARITY GFX_ACTIVE_HIGH define GFX_HSYNC_POLARITY GFX_ACTIVE_LOW define GFX_VSYNC_POLARITY GFX_ACTIVE_LOW define GFX_DISPLAYPOWER_POLARITY GFX_ACTIVE_HIGH Configure
59. 603 R7 2141200 3 R EU RO603 R8 R9 R10 1 TPS2378 TPS2378 U1 2144277 1 MCP1650S E MS MCP1650S E MS U2 1863920 1 R1LV0816ASB U3 2068162 1 TL2475TL2575HV 33 TL2475TL2575HV 33 U4 1755280 1 PIC24FJ256DA210 PIC24FJ256DA210 U5 1823150 1 M29W320DT U6 1099698 1 LAN8720 U7 2292577 1 PIC32MX695F512L PIC32MX695F512L U8 1778489 1MOLEX 54104 4031 MOLEX 54104 4031 x1 1757126 1 MOLEX_52271 0679 MOLEX_52271 0679 X2 1079950 2 CRYSTALHC49UP Y1 Y5 1611765 1 Buzzer BUZZERSMD3 Y2 1192962 1 25MHz ABMM1 Y3 1611797 1 OSC XTALTC 26 Y4 1611828
60. 8C connector with integrated transformers was used in the PoE PD prototype The chosen connector 0838 1X1T W6 was rather big with a height of 13 97 mm and a massive depth of 38 1 mm There were few other alternatives when one of the requirements was PoE compatibility Many 8P8C 42 CHAPTER 5 ETHERNET connectors with integrated transformers do not provide access to all the plug s pins and the center taps of the transformers A much smaller connector is desired so a different solution is sought for the OOD prototype 13 97 11 25 6 6 a 2 55 Figure 5 4 Height of the 0813 1X1T W6 left compared to TM25RS 5CNA 88 right If the connector and transformers are separated the selection of both components increase greatly A transformer package with a height of no more than 6 35 mm Halo TG110 RP55N5 was selected based on the recommendations for LAN8720 35 On the look for a slim 8P8C connector the TM25RS 5CNA 88 was discovered The TM25RS is a collapsible connector seemingly one of its kind which makes it possible to make very slim Ethernet capable products Although the collapsible feature is not needed since the cable will always be present it is still the slimmest alternative for an 8P8C connector Figure 5 4 illustrates the height of the TM25RS collapsed and opened compared to the 0838 1X1T W6 Sheet 6 in appendix C shows the connector transformers pull up resistors and other components as recommended by the LAN8720 datasheets
61. B INTERFACE code see appendix A The Add new button sends a GET request to con fig getNewAvailTypeDefVals html which creates a new availability with an avail able ID and a set of default values The data returned from this request holds the same format as that returned from config getAllAvailTypes html which is used to load all the availabilities The format is listed in table 23 2 Configuration Set name and title Back Name and title Make sure that name and title will fit on the display depends on length and number of words Title may be empty Use only latin 1 characters Full name Sigmund Segfault amp Title Staff Engineer x Figure 23 6 Name and title configuration page in web UI This menu page is very simple It contains a form with input elements for the name and the title as shown in figure 23 6 The name must be non empty but the title can be empty There are no fixed limits on name and title lengths other than buffers in the HTTP server so it is the owner s responsibility to ensure that the information will fit on the display Configuration Network Figure 23 7 on the facing page shows the network configuration menu where all the network settings can be adjusted Care is taken in the backed to not apply any settings unless all the parameters in the form are valid However this does not prevent the owner from configuring the OOD to an unreachable state so care 23 5 OUTLINE OF A PAGE WITH
62. BLY AER Figure 10 9 LAN8720 crystal fix Buzzer not working The buzzer had by mistake been connected to an output compare pin instead of the PWM output pin which had a similar naming OLOUT OC1 This can be remedied by controlling the pin in software instead of purely by the PWM 10 7 TESTING AND VERIFICATION 77 hardware module Unresolved parallel flash issues It was not possible to get the parallel flash to behave as expected when using the developed software driver Reads were sometimes inconsistent and the flash reported errors when writing operations were attempted No electrical errors were found and the driver being almost a mirrored copy of the driver used successfully with the flash on the development board did not seem to contain any bugs No solutions were found to this problem Hardware Discussion The PCB turned out well despite the relatively big design error which was the placement of a series of components on the wrong side as illustrated in figure 11 1 There were a few minor flaws all of which could be corrected with some bridges and solder Given the limited experience in PCB design the outcome must be said to be satisfactory Nonetheless there is always room for improvements Are the selected components suitable or could they have been replaced by better alternatives Could the overall design have been done differently The errors in the design should also be discussed How could they have been
63. CK SHUTDOWN GND TL2475TL2575HU 33 TPS2378 PoE ood 421718 1143 PH Sheet 1 1 6 1 3 5 PMD4 PMD3 PMD2 HSYNC USYNC 10pF tantalum PMAL6 ai q GCLK Chip program UDD connector A PI PIC24 ICSP Goa 6D8 PMD1 1C24_MCLR 6D1 PMDO JP1 MCS2 PMAL7 GND PMAS GEN PMA4 D8 PMA3 D9 D18 PMAZ D11 GND UDD IO oo y ON 07 a JO IN IE 1 2 3 4 5 PGED1 PGEC1 D15 D14 PIC24_MCLR PIC24 PIC24 PMCS1 PMA19 GND BKLT_PWM GD4 6D5 GD6 E 10pF tantalum LBR 6 3U D13 D12 1C24_DEBUG_TX D11 D7 ND 1C24_DEBUG_RX Graphics storage parallel flash _ de nooo PIC24_PGEC1 s PMag 25 ay Dog Pg PMD PIC24_PGED1 PMAL 24 po Pl PMDL MCUCOM PIC24F J256DA210 e ee e puaa a 93 be be PMD4 MAS PMAS 20 PMD5 UDD PMas 18 pos 2 PMD6 A15 PMA7 18 gt 4 PMDZ D10 PMAB 8l 00 faa pmo8 UCOM_SDO PMAS Z PMDS TOUCH_SDA gt i PMALB l 34s PMD1 TOUCH_SCL Primary oscillator pmai1 5 Be PMD11 GND H I l I 1 1 1 1 1 L Li l UOOQUUUUUUU OUCH_INT MAL4 QUO E oO PMA12 4 B9 ____ PMD12 PMA13 3 41 PMD13 PMA14 2 43 PMD14 UD PMA1S 1 45 PMD15 PMA16 48 E p6 PMCS2 PMAL7 12 28 PMRD PMA18 16 11 PMUR PMA19 UDD PMAZB 18 LS UDD ie _ UDD GND 2782 UDD USR_LED1 GDS GD3 Ayr MCUCOM_SCK
64. CN20 RD14 AETXDO 51 USBID RF3 54 VBUS 55 VUSB 56 D RG3 57 D RG2 58 SCL2 RA2 59 SDA2 RA3 60 TDI RA4 61 TDO RAS 66 AETXCLK SCL1 INT3 RA14 AETXCLK 67 AETXEN SDA1 INT4 RA15 AETXEN 76 OC2 RD1 Pin Functions 77 OC3 RD2 79 ETXD2 IC5 PMD12 RD12 80 ETXD3 PMD13 CN19 RD13 81 OC5 PMWR CN13 RD4 82 PMRD CN14 RD5 84 ETXCLK PMD15 CN16 RD7 89 ETXERR PMD9 RG1 90 PMD8 RGO 91 TRCLK RA6 92 TRD3 RA7 93 PMDO REO 94 PMD1 RE1 97 TRDO RG13 98 PMD2 RE2 99 PMD3 RE3 100 PMD4 RE4 PIC32 pin allocation Function used Purpose Purpose details Alt function Moveable Schematic circuit diagrams The following pages include the complete schematic circuit diagrams for the OOD The schematics match the PCB produced and include the errors mentioned in 10 7 The BOM can be find in appendix D on page 235 The last sheet is the diagram for the Newhaven Display adapter Sheet 1 Display This sheet includes the following e LED driver e Display fram buffer SRAM U3 e Display connector X1 e Display touch controller connector X2 e EC termination Sheet 2 PoE This sheet includes the following e PoE controller U1 with necessary circuitry e DC DC converter U4 with necessary circuitry e Inrush current limiter Sheet 3 PIC24 This sheet includes the following e PIC24FJ256DA210 microcontroller U5 with necessary circuitry 225 226 APPENDIX C SCHEMATIC CIRCUIT DIAGRAMS Parallel flash U6 e PIC24 ICSP connector JP1 e
65. Capacitor 39 42 will not be populated but allows for electromagnetic compatibility EMC flexibility 5 4 PCB placement and layout considerations The LAN8720 placement checklist 42 and routing checklist 50 will be followed to the greatest extent possible when designing PCB Some of recommendations from these papers are e Place the 8P8C connector transformers and LAN8720 as close together as possible but The distance between the connector and transformers should be between 12 7 mm and 19 0 mm The distance between the transformers and LAN8720 should be between 25 4 mm and 76 2 mm 54 PCB PLACEMENT AND LAYOUT CONSIDERATIONS 43 Place no other components in or near the TX RX differential signal lanes Place the crystal and bulk and decoupling capacitors as close to the LAN8720 as possible Keep the length of the RMII traces under 150 mm Keep the differential impedances at 100 2 Avoid traces and planes underneath the differential traces between connec tor and transformers The recommendations also included more details on digital ground and power planes but since this is a two layer board no planes will be used around the differential signals Non volatile memory The OOD needs a place to store settings calendar data and portraits Both microcontrollers need access to memory the PIC32 mainly for web and calendar data the PIC24 for graphics elements and fonts Instead of using a memory device that can be used
66. Ds RMII and crystal 0000 41 5 3 Connector and transformers a 41 5 4 PCB placement and layout considerations 42 6 Non volatile memory 45 6L microSD card s rar BR ee EE eee ee ees 45 Necessary connections 2 2 0000000000002 46 6 2 Parallel flash 0 ge 282 0002 a a ee ee D A 46 Necessary connections 2 2 eee 47 7 Graphics and display 49 7 1 Display capacitive touch controller 49 CONTENTS 7 2 Display prototyping adapter o LED driverdesien 4 mau at a nen a Connecting RGB and control signals POB design sai a cda ia a te ded Tar ORAM ae A he Are eer te ca as nr re A 7 4 Double buffering asenu a sae AAA EER A 7 5 PCB design considerations 0 2 0 20004 8 Power over Ethernet 8 1 Inrush current limiter 2222 oo oo onen 8 2 PoE controller and DC DC converter 9 Near field communication 9 1 PN532 10 PCB design and assembly 10 1 Software tools used 22 22 2m ee 10 2 Finalising circuit 10 3 Placing components 000000000000 10 4 Finished design 10 5 Fabrication Results 10 6 Assembly 10 7 Testing and verification o a Inrush current limiter problem LAN8720 crystal problem 2 2 2 2 o ooo Buzzer not WOTkidg e e e Unresolved parallel flash issues o 11 Hardware
67. EG UDDCORE RD RD6 RD5 RD4 RD13 RD12 RD3 RD2 RD1 ussi RC14 RC13 RDO RD11 RD10 RD9 RD8 RA15 RA14 USS5 RC15 RC12 UDD5 TDO TDI RA3 RA2 USR_LED2 DHCP_LED BUZZ PHM 10pF tantalum 1N 6U RTC oscillator GND SD MOSI Y4 MDC 1 SD_SCK SD_CS C33 C34 MDIO A GND UDD MCUCOM SDI MCUCOM SDO PIC32_DEBUG_TX PIC32_DEBUG_RX GND 3 PIC32_DEBUG_UART 4 21 13 11 43 PM Sheet 1 1 6 3 REFCLK CRS_DU Ethernet transciever TXD TXD1 TXEN RXD8 MODEB RXD1 ODET RXER PHYADG MDIO MDC NINT REFCLK CRS_DU MODE2 XTAL1 CLKIN XTAL2 NRST UDD2A UDD1A UDDCR UDDIO RBIAS TXP TXN RXP RXN LED1 REGOFF LED2 NINTSEL UDD 16U gt 1 F lt 12 tantalum UDDC UD Rss Leza cx TX_ TX_ RX_ RX_ LINK_LE 100M_LE R33 100M_LED 10k9 a 121k 1 vo tantalum l Fl 6 3U GND 10pF tantalum CHASSIS GND 1nF 2kU TG110 E055 C43 22nF 58U ANAGTAWNE TM25RS SCNA 88 POE AL POE_A2 ll C38 Ethernet ood ALZA PU Sheet 1 1 6 BKLT_PWM driver VIN EXT NC 1 GND NC 2 CS SHDN FB PICe x4 graphics connector J2 BKLT
68. ETXD1 PMD11 RFO ETXD1 Ethernet TXD1 Yes 83 ETXEN PMD14 CN15 RD6 ETXEN Ethernet TXEN Yes 40 SS4 U5RX U2CTS RF12 U5RX NFC NFC UART RX Yes 39 SCK4 U5TX U2RTS RF13 U5TX NFC NFC UART TX Yes 63 OSC1 CLKI RC12 OSC1 Oscillator Main oscillator 64 OSC2 CLKO RC15 OSC2 Oscillator Main oscillator 73 SOSCI CN1 RC13 SOSCI Oscillator RTCC oscillator 74 SOSCO T1CK CNO RC14 SOSCO Oscillator RTCC oscillator 30 AVDD AVDD Power 31 AVSS AVSS Power 85 VCAP VDDCORE VCAP Power 2VDD VDD Power 16VDD VDD Power 37 VDD VDD Power 46VDD VDD Power 62 VDD VDD Power 86 VDD VDD Power 15VSS VSS Power 36 VSS VSS Power 45 VSS VSS Power 65 VSS VSS Power 75VSS VSS Power 19 AERXD1 INT2 RE9 INT2 SD card SD card detect AERXD1 Yes 70 SCK1 IC3 PMCS2 PMA15 RD10 SCK1 SD card SD card SPI SCK Yes PIC32 pin allocation Pin Functions Function used Purpose Purpose details Alt function Moveable 32 AN8 C10UT RB8 amp 1 AERXERR RG15 AERXERR 3 PMD5 RES 4 PMD6 RE6 5 PMD7 RE7 6 T2CK RC1 7 T3CK RC2 8 TACK RC3 10 ECOL SCK2 U6TX U3RTS PMA5 CN8 RG6 11 ECRS SDA4 SDI2 U3RX PMA4 CN9 RG7 17 TMS RAO 18 AERXDO INT1 RE8 AERXDO 20 AN5 C1IN VBUSON CN7 RB5 21 AN4 C1IN CN6 RB4 22 AN3 C2IN CN5 RB3 23 AN2 C2IN CN4 RB2 26 PGEC2 AN6 OCFA RB6 27 PGED2 AN7 RB7 28 VREF CVREF AERXD2 PMA7 RA9 29 VREF CVREF AERXD3 PMA6 RA10 33 AN9 C20UT RB9 34 AN10 CVREFOUT PMA13 RB10 38 TCK RA1 43 AN14 ERXD2 AETXD3 PMALH PMA1 RB14 44 AN15 ERXD3 AETXD2 OCFB PMALL PMAO CN12 RB15 47 AETXDO SS3 UARX U1CTS
69. ET_TX_SIZE HTTP_SOCKET_RX_SIZE Code listing 20 7 Array used to initialise TCP sockets Using MPFS to convert files In order to connect the previously mentioned HTTPPrint methods to the actual tilde enclosed dynamic variables in the HTML source a tool called MPFS2 jar must be used MPFS2 parses the source files and generates the HTTPPrint h file with declarations of all the required dynamic variable callback functions and the two binary files DynRerd bin and FileRerd bin The tool also comes with other features for example file compression or the option of converting the HTML source into a format suitable for being stored in the microcontroller s program memory Using the MPFS2 tool is straightforward Choose the web page source directory and output directory choose MDD as output type format and click Generate A pop up will tell you if the HTTPPrint h has changed since the last run which implies that the program code needs to be recompiled Figure 20 5 on the next page shows a screen shot of the program 20 6 SSL The SSL part of the TCP IP stack has up until the last version of the MAL v2013 02 15 not been included due to US Export Control restrictions It was necessary to buy a CD with the source code affected by the export restrictions for a nominal fee which was done in the beginning of the thesis work It is not known why this is no longer required but it makes it a lot easier to use TCP IP stack wit
70. FC reader 23 Web interface 23 1 Limitations and considerations 23 2 Frontend 23 3 Selecting application framework 23 4 Development environment 2 222 2 2 m nn nn 23 5 Outline of a page with jQuery Mobile Web interface menu structure 2 2 En nn nn 23 6 Encoding considerations and bilingual support 24 Software Discussion 24 1 TCP IP stack 24 2 Web development 24 3 GUI development 25 Software Conclusion xi 139 139 139 140 141 141 144 146 148 151 153 155 155 157 158 158 161 165 165 166 167 168 169 169 171 172 173 174 176 183 185 185 186 186 189 xii CONTENTS IV End result 191 26 Testing and results 193 26 1 Web server and web UI 193 Robustness and error handling rn 193 Responsiveness and mobile access LL o nn 194 Web server performance e 195 SSL performance 2 2 2 2 e 197 TCP IP stack stability 2 o o nn 198 26 2 Display touch and GUI o o 200 27 Discussion and further work 201 27 1 Development using Microchip microcontrollers 201 20 2 OOD hardware os 0 2 es ae 202 27 3 TCPIP and web server performance 202 24 Further work a Pune es ee A ES G a SS 202 28 Conclusion 205 References 207 V Appendix 213 A Source code 215 Al MAL patch 2 Sr N eer e oaa eat 215 AS2 HTTP Ser
71. I24 18 PIC32 98 LAN87201 54 microSD card 100 mA Display 76 3 Sum 401 3 Near field communication Figure 9 1 The PN532 board Near field communication NFC is a set of standards for devices to establish radio communication with each other by bringing them into close proximimty 62 With NFC the OOD will be capable of reading common ID cards and communicate with smartphones The main motive for adding NFC support is implementing a way to read ID cards By allowing the owner to quickly identify himself and choose a new availability status upon leaving or entering his office it is more likely that the status on the OOD will be kept up to date Radio frequency identification RFID cards are common in areas with access control like NTNU and can be used by the owner to authenticate himself on the OOD Contactless smart cards like MIFARE are based upon ISO IEC 14443 type A which is a standard used in more than 80 of all contactless smart cards in use world wide 9 This makes 65 66 CHAPTER 9 NEAR FIELD COMMUNICATION NFC support much more attractive than alternatives like magnetic cards NFC support also adds many other possibilities to the OOD especially since newer smartphones support NFC With an application on the smartphone the owner can retrieve the IP address of the OOD upload a new portrait set a new status or simply just authenticate 9 1 PN532 The chip used for NFC communication will be PN532 It is chosen
72. IFICATION 15 Plug and play It is important that the OOD can be used in an environment without the need for specialised hardware and cabling Ethernet 10BASE T 100BASE TX is commonly found as a part of office infrastructures Speed Even the lowest rate supported by the Ethernet standards 10BASE T with 10 Mbit s 24 is sufficient for web content and smaller pictures It is more likely that other parts of the system will be a bottleneck Two drawbacks with the chosen network technology is current consumption and the need for a cable with a relatively large connector The tested Ethernet transceivers and controllers in 66 drew up to 200 mA of current and dissipated a lot of heat The 8P8C connector needed also poses challenges due to its bulky size These are areas of improvement the Ethernet controller transceiver should draw as little current as possible and the 8P8C connector and transformer casing need to be be as small as possible In addition to support 10BASE T 100BASE TX 1000BASE T the chosen hardware needs to communicate with the microcontroller fast enough to utilise the speed of these standards Power supply PoE was chosen in 66 to transport power along with data in a single cable A powered device PD prototype with a DC DC converter was designed and tested in the preliminary design The only flaw with the design was the lack of inrush current limiting A refinement of this design which can provide enough power
73. JQUERY MOBILE 181 Back Network settings Temporary changes will be reset when rebooted No Enable DHCP CH Please use dot decimal notation for the IP addresses IP address Subnet mask Gateway address Primary DNS address Secondary DNS address Figure 23 7 Network configuration menu in web Ul 182 CHAPTER 23 WEB INTERFACE emporary changes will be reset when rebooted Set Time SNTP Set Time Figure 23 8 Time and date configuration menu in the web UI should be taken when setting up the network There are two methods to revert incorrect settings 1 Remove the memory card A set of default settings will be loaded These can be adjusted in ood pic32eth X config netwSettings c 2 Use the UART command interface to enable disable DHCP When a lease is acquired the new IP address will be printed Network settings will also be printed during boot Configuration Time and date In this menu the date and time can be manually set and the settings for SNTP can be modified A new SNTP update can also be requested The form in this menu needs date and time inputs which is cumbersome for the user to enter without aids The HTML5 standard introduced new input element types specifially to handle date and time When these input fields are encountered the browser provides native input methods which on a mobile device should be a comfortable touch optimised method Unfortunately this support is yet far from
74. NTNU Trondheim Norwegian University of Science and Technology Implementing an Out of Office Notification System Andreas Misje Master of Science In Engineering Cybernetics Submission date July 2013 Supervisor Amund Skavhaug ITK Norwegian University of Science and Technology Department of Engineering Cybernetics Problem description In office environments it may be challenging to get hold of colleagues when they are not in their offices A simple remedy may be to use sticky notes explaining one s absence and for how long A flaw with this solution is the lack of being able to update the message and keep the information up to date In previous work a design is proposed for an electronic system that replaces a name sign a portrait and absence notes The device con sisting of a colour LCD display and an Ethernet network connection makes it possible for an office occupant to update text on the dis play remotely The main use case is keeping co workers up to date on one s absence but the interactive display opens for other possibilities The objective is to make a device based on the proposed design in cluding both hardware and software Part of the objective is to base the system on microcontrollers in order to explore the limits of GUI TCP IP and encryption on resource limited systems A lesser known family of microcontrollers will be used to gain competence on non Atmel products at the Department of Engineering Cyberneti
75. OCORE R2 1000 to 4700 q C1 Tey Note 1 See Section 2 4 Voltage Regulator Pins L PIC24FXXXX al ENVREG DISVREG and Vcap VDDCORE VDD u for explanation of ENVREG DISVREG pin cel f NSS c3 connections vss 2 The example shown is for a PIC24F device yon a 2 with five VDD Vss and AVDD AVSss pairs z z Other devices may have more or less pairs a an o n gt gt adjust the number of decoupling capacitors appropriately c52 c42 Figure 4 3 Recommended minimum connections for PIC24F from 34 p 33 4 3 PIC32MX695F512L With the PIC24 driving the display the only special requirement for the second microcontroller is that it can handle the Ethernet connection Although there are numerous ways to implement Ethernet in an embedded system as discussed in 66 the decision in chapter 5 is to use a RMII capable Ethernet transceiver along with a supporting microcontroller With MII RMII support and an integrated Ethernet controller the PIC32MX695F512L also boasts 512 kB of program memory 128 kB RAM eight direct memory access DMA channels 80 MHz system clock and many peripherals With its great computing power and twice the amount of flash than that of the PIC24 the PIC32 will host most of the software 4 3 PIC32MX695F512L 35 M4K 32 bit core 5 stage pipeline 32 bit ALU MIURMII 32 core registers 10 100 HW multiply divide Signed 32 bit x 32 bit Shadow set 2 ch DMA 4 ch DMA 2 ch DMA fro
76. P bus It was a challenge to come up with such a compact result on two layers and it was almost impossible to keep the length of the traces equal However the signals are not of very high frequencies so the uneven lengths will hopefully not be a problem Having the PIC24 SRAM and flash on one side 10 5 FABRICATION 71 Figure 10 3 Close up of the EPMP signals in the PCB design and the display connector on the other appeared to be the best arrangement for optimal routing Having components on both sides may impose an increased manufacturing cost so this choice should be reconsidered if the OOD is to be mass produced For this thesis the PCB will be soldered by hand Figure 10 4 on the following page shows a close up of the Ethernet area of the PCB The connector is partially visible in the lower right where the differential TX and RX pairs start They travel into the transformer housing and the signals going back are the center taps of the transformers used for PoE The squiggly lines are inserted to match the length of the pair The absence of a ground plane is as recommended by the LAN8720 PCB checklists 10 5 Fabrication The fabrication service used is ITEAD s PCB prototyping service They were chosen because they have proved to fellow students to provide good results to a good price with very short lead times The product chosen was their Inttp imall iteadstudio com open pcb pcb prototyping html 72 CHAPTER 10 PCB
77. PM newhavendisplay com app_notes FT5x06 pdf 2010 Accessed Feb 14th 2013 ENC424J600 ENC624J600 Data Sheet Stand Alone 10 100 Ethernet Controller with SPI or Parallel Interface 2010 FT5x06 True Multi Touch Capacitive Touch Panel Controller http www focaltech systems com Upload products downloadfile FT5x06Datasheet_FocalTech 10440789024 pdf 2010 Accessed Feb 14th 2013 PIC24FJ256DA210 Development Board User s Guide 2010 PICFJ256DA210 Family Data Sheet 2010 AN 8 13 Suggested Magnetics 2011 Free Pool of IPv4 Address Space Depleted http www nro net news ipv4 free pool depleted 2011 Accessed Dec 17th 2012 PIC32 Family Reference Manual Section 23 Serial Peripheral Interface 2011 PIC32 Family Reference Manual Section 35 Ethernet Controller 2011 PIC32MX5XX 6XX 7XX High Performance USB CAN and Ethernet 32 bit Flash Microcontrollers 2011 Samsung SD amp MicroSD Card product family 2011 Section 42 Enhanced Parallel Master Port EPMP http ww1 microchip com downloads en DeviceDoc 39730B pdf 2011 Component Placement Checklist for the LAN8720 24 pin QFN Package 2012 FatFs Generic FAT File System Module http elm chan org fsw ff OOindex_e html1 2012 Accessed Dec 18th 2012 FatFS implementation for PIC32 http www microchip com forums tn aspx m 563218 2012 Accessed Nov 16th 2012 Graphics Library Help Part of the Microchip Application Library help d
78. Prototype http prototypejs org e YUI http yuilibrary com e Dojo http dojotoolkit org e RightJS http rightjs org e Enyo http enyojs com e Knockout http knockoutjs com index html e AngularJS http angularjs org e qooxdoo http qooxdoo org e The M Project http www the m project org e Query Mobile http jquerymobile com e jQT http jqtjs com e Sencha Touch http www sencha com products touch After a careful review of the alternatives considering their easy of use code size browser support mobile support cost licensing and documentation the best alternative is Query Mobile Query Mobile is built upon Query which is a very popular library Query Mobile comes with a MIT license good documentation nice looking responsive web sites and widgets form inputs buttons sliders panels pop ups etc that are easy to use and work well on both newer and older mobile browsers Depending on the relatively heavy Query library 91 kB minimised as of version 1 10 1 is a downside but on the other hand it is a library many other plug ins depend on which reduces overall libraries and dependencies 23 4 Development environment An old HTC Desire smartphone will act as the main mobile test device along with occasional tests on modern phones with more modern browsers than the one provided with Android 2 2 2 The desktop browsers used are Mozilla Iceweasel 17 0 6 and Chromium 27 0 14
79. RC3 GD1 Graphics 69 DPLN RP4 GD10 PMACK2 CN54 RD9 GD10 Graphics 77 DPH RP23 GD11 PMACK1 CN51 RD2 GD11 Graphics 32 AN8 RP8 GD12 CN26 RB8 GD12 Graphics 33 AN9 RP9 GD13 CN27 RB9 GD13 Graphics 47 RPI43 GD14 CN20 RD14 GD14 Graphics 48 RP5 GD15 CN21 RD15 GD15 Graphics 39 RP31 GD2 CN76 RF13 GD2 Graphics 52 RP30 GD3 CN70 RF2 GD3 Graphics 21 PGED3 AN4 C1INB USBOEN RP28 GD4 CN6 RB4 GD4 Graphics 22 AN3 C2INA GD5 VPIO CN5 RB3 GD5 Graphics 23 AN2 C2INB VMIO RP13 GD6 CN4 RB2 GD6 Graphics 76 VCPCON RP24 GD7 VBUSCHG CN50 RD1 GD7 Graphics 7 RPI39 GD8 CN46 RC2 GD8 Graphics 53 RP15 GD9 CN74 RF8 GD9 Graphics 91 AN23 GEN CN39 RA6 GEN Graphics 27 PGED2 AN7 RP7 RCV GPWR CN25 RB7 GPWR Graphics 97 HSYNC CN80 RG13 HSYNC Graphics 96 VSYNC CN79 RG12 VSYNC Graphics 51 RP16 USBID CN71 RF3 RP16 MCU com MCU com SPI SCK Yes 68 DMLN RTCC RP2 CN53 RD8 RP2 MCU com MCU com SPI MOSI Yes 26 PGEC2 AN6 RP6 CN24 RB6 RP6 MCU com MCU com SPI MISO Yes 44 AN15 REFO RP29 PMAO CN12 RB15 PMAO Parallel bus Address bus 43 AN14 CTPLS RP14 PMA1 CN32 RB14 PMA1 Parallel bus Address bus 42 AN13 PMA10 CTEDG1 CN31 RB13 PMA10 Parallel bus Address bus 41 AN12 PMA11 CTEDG2 CN30 RB12 PMA11 Parallel bus Address bus 35 AN11 PMA12 CN29 RB11 PMA12 Parallel bus Address bus 34 AN10 CVREF PMA13 CN28 RB10 PMA13 Parallel bus Address bus 71 RP12 PMA14 PMCS1 3 CN56 RD1 1 PMA14 Parallel bus Address bus 70 RP3 PMA15 PMCS2 3 CN55 RD10 PMA15 Parallel bus Address bus PIC24 pin allocation Pin Functions Functi
80. RL decoded result The possible return values of the type HTTP IO RESULT are listed in table 20 4 Table 20 4 HTTP IO RESULT return values HTTP IO DONE Processing is done HTTP IO NEED DATA More data is needed the name value is not vet completelv read into buffer HTTP_IO_ WAITING The callback is waiting for an asyn chronous process to complete As long as the callback returns something other than HTTP_IO_ DONE it will be called again and repeated until it is done Modifications It is difficult to write a generic POST processing function aiming to handle all the POST requests the server is designed to handle Parsing POST requests proved to be complicated when writing backend code for the web Ul and it was preferred to separate the POST processing routines into modules depending on the type of data the routine was handling And more importantly a way of determining the source sender of the request was needed There is no way to retrieve the file name of a file handle in FatFS and the file name in the HTTP query is lost past the PARSE states in the server Supplying the source as data in the POST request would neither work An extension to the HTTP server was clearly needed and was implemented as a look up table mapping file name to an 1D which in turn is used to call the appropriate callback The function static BYTE getPOSTFileID BYTE fileName is added to the HTTP server and it is called in the PARSE REQUES
81. STEM DESIGN Ola Ne gel aatelala Important title AVAILABLE until 16 00 Portrait i Availability Pease ese eee eee eee Figure 2 3 Main sections of the default menu page Availability It is not always necessary to display a photo Removing the picture gives more room for the name and title This is designed to be possible to do from the control panel The availability field consists of a large font describing the type of availability that is whether the office occupant is available present but busy at lunch or away for the day A second optional line describes the status further and a duration tells for how long this status is valid The background colour is meant to indicate the type of availability Green would mean that the person concerned is present and does not mind being disturbed whereas red or orange could mean that he or she is absent or busy These colours shall be for the owner to choose A small portion of the display will also be used to show useful information like the current time and information about the network connection a broken connection would mean that the information may no longer be up to date and valid A touch anywhere on the display or on a menu button if deemed necessary opens the main menu allowing passer bys to any of the following e Check the office occupant s public schedule in order to see whether he or she is available in the near future 2 2 MAIN COMPONENTS 13
82. T state see figure 20 3 in time before the buffer where the file name lives is re used and data lost The returned ID is stored in the HTTP__CON connection specific state variable and is later used in HTTPErecutePost to call the correct function Listing 20 4 on the next page shows the look up table defined in TCPIPConfig h 67 68 69 70 72 73 74 75 76 TE 78 79 80 82 83 84 85 86 87 150 CHAPTER 20 TCP IP STACK along with matching constants which eases readability in the switch that uses ID to choose appropriate callbacks in HTTPErecutePost The symbol definition checks are necessary to exclude the enum and array for when the file is included from an assembly file in MAL ood pic32eth X TCPIPConfig h tif defined __HTTP2_C defined FORM H HTTP POST configuration Maps file name in URL in POST requests to a an ID which in turn will map to an appropriate callback function enum POSTFileNamelDs POSTFileName_network 0 POSTFileName_time POSTFileName_availType POSTFileName_bio 3 endif defined __HTTP2_C defined FORM H tif defined __HTTP2_C const char POSTFileIDMapping POSTFileName_network config networkPOST html POSTFileName time config timePOST html POSTFileName availTvpe config availTypeP0ST html POSTFileName bio config bioPOST html endif __HTTP2_C Code listing 20 4 POST file ID look up table Another is
83. T5X06 DRIVER 111 IBC STATE ack Driver is acknowledging reception 12C STATE error Driver is in an error state The driver enters this state if anv of the following occurs 1 Slave did not acknowledge 2 An unexpected FC interrupt occurred 3 A bus collision was detected 4 TX RX buffer could not fit provided data I2C STATE disabled Driver is temporarily disabled by i2c_disable Data reception and transmission is performed in the interrupt routine and requires no manual intervention The driver status must be inspected regularly in order to determine whether the transmission or reception has completed or whether anv errors have occurred Since onlv either transmission or reception may occur at a time they share the same buffer Listing 16 1 on the next page shows the implementation of the i2c puts function The i2c gets function is implemented in a similar fashion Data is copied from the TX RX buffer into a provided array by calling i2c getData Appendix A contains the full implementation and documentation of the PC driver 16 2 FT5x06 driver The FT5x06 driver provides two functions void ft5x06 quervTouchinfo int numPoints which send a query command to the touch controller and int ft5x06_retrieveTouchInfo struct touchInfo touchInfo which parses awaiting data in the 12C RX buffer and updates events coordinates and gesture info in the provided touchInfo object In order to limit the traffic on the I C bus on
84. _PWM GND GEN HSYNC GD14 6D128 6D8 GD3 6D12 GD6 GD1 pH re FT5x 6 touch controller pull up JP1 R5 me U G G G G G G G G G G G G G G G G G G G G G G G G G G G H U G Zz oO newHavenAdapter 27 11 13 2 58 PM Sheet 1 1 6 Bill of materials The following pages include the bill of materials Pricing info has been removed in order to make the table much more compact The part number is listed for Farnell where possible Remaining parts were either personally available or bough from Digi Key 235 Bill of materials Qty Value Device Parts Fanrell part no 6 LEDSMLO603 100MBPS DHCP OK LINK ACT PWR USR LED1 USR LED2 2099227 2 DFO1S DFO1S B1 B2 1470959 1 1uF 100V C EUC0805 C1 1907331 410uF lt 50 6 3V CPOL EUCT3216 C10 C12 C29 C30 197014 2 27pF C EUC0402 C13 C14 1828877 1 10uF 16V CPOL EUA 3216 18R C2 1650980 1 gt 1uF lt 1Q tantalum C EUC1210 C22 1432587 1 470pF C EUC0402 C23 1907276 2 01 UF C EUC0402 C24 C25 1692285 1 10uF lt 10 6 3V CPOL EUCT3216 C27 1135229 1 10uF 35V CPOL EUCT6032 C3 1754232 2 30pF C EUC0402 C31 C32 1758954 4 22pF C EUC0402 C33 C34 C35 C36 3019184 1 1nF 2kV C EUC1210 C38 1886056 4 DNP C EUC0402 C39 C40 C41 C42 2 C EUC0805 CA C5 1 22nF 50V C EUC0603 C43 1520257 14 7uF tantalum CPOL EUCT3216 C50 2283560 1 100uF 63V CPOL EUG C6 9696040 C7 C8 C11 C15 C16 C17 C18 C
85. access to the filesystem the calendar module see chapter 19 needs write access to store data to file So do all the settings that need to persist between power cuts In order to make the system robust it is given the option to create missing directories requiring FS MINIMIZE lt 2 FS SHARE determines how many files that can be opened at a time Most routines do not need files to remain open apart from the web server making it the software component affecting this number the most Chapter 20 5 has more details about assumptions made for web traffic and number of clients The ffconf h file can be found in appendix A 1Part of the MAL 15 1 HOW THE LIBRARY WORKS 99 Table 15 1 FatFS configuration 4 Definition Description Value _FS TINY 1 Shared sector buffer or 0 individual 0 buffer per file _FS READONLY 1 Exclude all writing functions 0 _FS_MINIMIZE 0 3 Various levels of excluding func 0 tions 0 everything included _USE_STRFUNC 1 Enable string functions 0 USE MKFS 1 Enable function for filesystem format 0 ting _USE FORWARD 1 Enable function for forward 0 ing streaming _USE_FASTSEEK 1 Enable a faster version of the seek 0 function _CODE_PAGE Which OEM code page to use together 1252 with LEN _USE_LFN Enable LFN support 1 global buffer 3 2 local buffer on stack 3 local buffer on heap _MAX_LFN Longest filename to support 255 _LFN_UNICODE 1 Use unicode for LFN filenames 0 _FS_RPATH 1 Enab
86. address location should be performed to see if the data was indeed written 26 The DQ6 line doubling as a status register bit during writes is continuously read during the program operation in order to see if the operations has finished It toggles when the device is busy see line 237 in appendix A for details 17 2 EPMP bypass mode In order to make any EPMP operation work when the module is controlled by the graphics controller the graphics controller must be told to relinquish control This is done by setting the MSTSEL bits in the PMCON2 register to 0 CPU and back to 3 Alternate Master I Os direct access EPMP bypass mode for every operation in the driver 41 p 7 17 3 Problems When testing the driver it was discovered that the flash did not behave as expected It performed reads successfully most of the times easily tested by reading the manufacturer and device ID but struggled with write operations With the driver working perfectly on the SST39VF400A it was quickly asserted that the software was not to blame Countless hours have been spent testing different timing configurations and the hardware has been inspected numerous times No solution was found to the problem and without storage for graphics data it was difficult do develop the GUI Graphics library Application layer Touch 2 ons screen l Message interface Object laver Push button Progress bar i Picture Primitive layer Primit
87. alising a special memory area in the microcontroller with a series of configuration constants In the PIC24 this is done as shown in listing 22 1 by using a macro which initialises one of the three configuration registers In PIC32 a series of pragmas are used Listing 22 2 on the next page shows an excerpt of the PIC32 configuration The remaining configuration for networking date and time calendar appointments and so forth is loaded from file In PIC32 all of these settings are loaded by calling loadSettings This function attempts to load configuration for all modules If loading a configuration file fails it will print an error message to stdout and load a set of factory settings instead settings set at compile time None of the file formats used are meant to be human readable and are simply a direct serialisation of data Most strings are stored with support for variable 165 e A 22 23 24 25 166 CHAPTER 22 OTHER MODULES AND SOFTWARE ood pic32gfx X config PICConfig h pragma config IESO OFF Internal external switch over pragma config FNOSC PRIPLL Oscillator selection pragma config FPLLIDIV DIV 2 PLL input divider pragma config FPLLMUL MUL_20 PLL multiplier pragma config FPLLODIV DIV_1 PLL output divider Code listing 22 2 Excerpt of the PIC32 configuration length and loaded as dynamic strings They are therefore always saved including their
88. ame time id time type date data role datebox data options H mode timeflipbox defaultValue time value time gt Code listing 20 2 Example of how to use dynamic variables HTML code ood pic32eth X http configTime c void HTTPPrint_time char buffer 6 struct tm t getRTCCDateTime snprintf buffer 6 02u 02u t tm hour t tm min TCPPutString sktHTTP buffer Code listing 20 3 Example of how to use dynamic variables C code Listing 20 2 to 20 3 on this page shows an example where a dynamic variable is used to print the current time from the real time clock RTC as the current value 20 5 HTTP SERVER 147 in an input field Note that the string is printed to the TX buffer in one go which is only possible for data up to certain length default is 16 bytes If it is necessary to send more data than there is currently room for in the transmit buffer the HTML server must be notified so that the callback can be called again when more room in the buffer is available The HTTP server provides a connection specific state variable that can be used for this purpose curHTTP callbackPos If this variable is non zero after calling a user callback the server process yields in order to wait for the transmit buffer to empty The dynamic variable feature can also be used to include whole files which can be very useful where large portions of HTML files are common Th
89. and as long as the plans for the GUI are kept simple the software architecture presented Inttp qt project org 2http www gtk org 189 190 CHAPTER 25 SOFTWARE CONCLUSION in this thesis is well suited With a public web interface with the need to handle many users at a time a more advanced architecture should be considered The GUI tools discussed should cater for most GUI needs but implementing it may not be worth the hassle and time The level of language and Unicode support demanded will also have a lot to say for whether the graphics library is the right tool for the job Part IV End result Testing and results With the hardware developed tested and fixed it is time to install the software on the microcontrollers and test how well the system works Since the major focus in this thesis is on the networking the TCP IP stack tests and results again with focus the HTTP server will fill most of this chapter The remaining components will only be briefly mentioned 26 1 Web server and web UI The web server is evaluated in two steps First the web Ul is extensively tested in order to see if there are any glitches delays or unexpected behaviour in either the web source or the web server This will also capture any behaviour that affects the user s browsing experience that cannot directly be measured in numbers The second part is a stress test of the web server without the UI The purpose of this test is to measure its
90. ant bit MAC media access control MAL Microchip application libraries MDD Microchip Memory Disk Drive File System Library MDIX media dependent interface crossover MII media independent interface MIPS million instructions per second MIT Massachusetts Institute of Technology MSB most significant bit NFC near field communication NTNU the Norwegian University of Science and Technology NTP network time protocol OEM original equipment manufacturer ONFI Open NAND Flash Interface Working Group OOD out of office display OS operating system OSI Open Systems Interconnection OTG on the go PCB electronics printed circuit board PCle peripheral component interconnect express PD powered device PLL phase locked loop PoE power over Ethernet xxii LIST OF ACRONYMS PSE power sourcing equipment PWM pulse width modulation QFN quad flat no leads QVGA quarter video graphics array RAM random access memory RFID radio frequency identification RGB red green blue RMII reduced media independent interface RTC real time clock RTCC real time calendar clock RTOS real time operating system SD Secure Digital SNTP simple network time protocol SPI serial peripheral interface bus SRAM static random access memory SSL secure sockets layer TCP transmission control protocol TCP IP the Internet protocol suite TFT thin film transistor TLS transport layer security TP twisted pair TQFP thin quad flat package TSOP thin small outline package
91. arallel to load resources in the HTML file Since state variables had changed between handling the multiple requests from the browser the server crashed or froze When the browser was configured to only use one connection per server the problems disappeared 82 83 84 85 86 87 88 146 CHAPTER 20 TCP IP STACK Dynamic variables In order to make more dynamic web sites especially with the lack of server side scripting languages and CGI the HTTP server provides a means to replace sections of the served HTML file with output from callback functions This feature is not truly dynamic as the variable replacement is done at compile time but it makes it possible to build a backend which together with help from client side frameworks and JavaScript can make interactive web pages This is demonstrated in chapter 23 In order to use a dynamic variable with the HT TP server the following two steps must be followed e Place the variable surrounded by tildes in the HTML file The variable can occur numerous times and in numerous files If the variable contains parentheses like a function call the parameters in the parentheses will be passed to the callback as parameters e Write a function prefixed with HTTPPrint that returns nothing and takes as many parameters as designed The parameters can be of any type but can only be written in the HTML file as integers or symbols ood pic32eth X html config time html lt input n
92. ary is the amount of work needed to build menus Developing a GUI for an embedded device without an emulator ends up being a trail and error process taking a lot of time The code has to be compiled downloaded and tested on the device in order to get necessary feedback Microchip has a program called Microchip Graphics Display Designer X that aims to help with this It provides what you see is what you get WYSIWYG editing and code generation The latest version from 24th of May looks lhttp www microchip com stellent idcplg IdcService SS_GET_PAGE amp nodeld 2680 amp dDocName en544475 24 3 GUI DEVELOPMENT 187 promising but earlier versions available during development were not impressive and were not considered for use Software Conclusion With making the OOD based on microcontrollers being one the main objectives of this thesis it was expected to have to work a lot with low level software It has been shown that it is possible to implement a TCP IP stack along with 2048 bit SSL a FAT32 file system using a microSD card on a 32 bit microcontroller with limited RAM The microcontroller can run a web server which along with a few modifications is capable of hosting interactive web sites for multiple users at a time It is also shown that it is possible to implement a capable GUI on a low power 16 bit microcontroller without the need for an external graphics controller This proves that the microcontrollers and software used are
93. at there is room to spare A parallel flash will added to give the PIC24 a local fast storage faciliy It is deemed to be plenty of room on the PCB for another large IC and the price of flash is relatively low The only possible challenge is routing the many address and data lines to yet another IC on a two layer PCB The chosen device is a M29W320DT706E with a unit price of 20 92 NOK 17 23 NOK per 100 as of February 2013 at Farnell It comes in a thin small outline package TSOP and has a capacity of 32 Mbit and is accessible by using 16 bits Necessary connections Figure 6 3 on the next page shows the parallel flash connected to the PIC24 using the EPMP signal lines PMA are the address lines PMD the data lines PMWR 48 CHAPTER 6 NON VOLATILE MEMORY PMAG PMD PMAL PMD1 PMA2 PMD2 PMA3 PMD3 PMA4 PMD4 PMAS PMDS PMAS PMD6 PMA PMD7 PMAB PMD8 PMAS PMDS PMALO PMD10 PMA11 PMD11 PMA12 PMD12 PMA13 PMD13 PMA14 PMD14 PMA15 PMD15 PMA16 PMCS2 PMAL7 PMRD PMA18 PMHR PMA19 UDD PMA2 UDD UDD GND UDD Ape C16 GND GND Figure 6 3 Parallel flash circuit diagram write and PMRD read The WP line is connected to VDD and decoupled with a capacitor because this pin serves as a second power supply pin and allows write operations 26 p 13 Graphics and display In 66 a PowerTip PH480272T_005_111Q 480x272 TFT LCD display with a resistive touch overlay was suggested for the OOD The display s size and re
94. be accessed on the smaller of the two flat cables The touch controller is a FT5x06 capable of detecting and tracking up to five points at a time and capable of recongnising five different gestures The only documents available for this chip is through Newhaven and there are no complete datasheets published However just enough information is available to be able to communicate successfully with the controller and write a software driver FT5x06 provides two means of communication SPI and 12C 32 p 5 Only 49 50 CHAPTER 7 GRAPHICS AND DISPLAY the 12C bus can be used since the SPI pins are not routed to any of the display connectors 67 p 4 The I C clock line can be found on pin 3 and I C data line on pin 4 on the smaller display connector Pin 5 is the interrupt inverted signal from the controller but there is some confusion regarding whether pin 6 is the reset or wake signal The pin out tables on page 3 and 4 in 67 do not agree However close inspection of the routing and controller pin out reveals that this pin is connected to the reset signal not the wake signal Set up and use of the FT5x06 along with its features are discussed in chapter 16 7 2 Display prototyping adapter Before making the OOD schematics and PCB and in order to develop drivers for the touch controller along hardware design a display adapter is made The adapter s purpose is to route RGB and display control signals from the 0 5 mm pitch 40 cond
95. because it is very common and has open source software drivers available It supports SPI PC and UART can both read and write and can emulate ISO IEC 14443A ISO IEC 14443B and FeliCa cards 11 The IC needs a wire loop antenna in order to communicate with other devices In attemps to find suitable positions for the antenna on the PCB it was discovered the signals would not pass through the display on top A PN532 development board was used to test the signal through the Newhaven display and it could not read the MIFARE card on the other side Although it would seem impossible to add the PN532 with an antenna to the system an alternative solution is used A super slim and compact development board like the one used in the experiments as seen in figure 9 1 on the preceding page will act as an external reader writer connected to the OOD with a cable providing both communication and power It is not an ideal solution but it allows for developing NFC support until a better solution can be found UART will be used to connect the PN532 board since its the only available protocol on the pin out of the board PCB design and assembly The previous chapters have presented hardware components and how they are connected together This chapter will go through the process of transforming the circuit diagrams into geometric shapes that ultimately will dictate copper fills and holes on a finished PCB The main motivation behind making custom hardware is the
96. bject Part two contains all hardware related chapters Each chapter discusses hardware options for a major function of the OOD A component fulfilling the 1 3 OUTLINE OF THE THESIS 7 specification is chosen and any necessary details on how to configure and use the component is given Chapter 10 PCB design and assembly explains the process of designing the PCB and discusses the manufactured and assembled result Part three starts by explaining the software architecture how libraries will be selected and mentions the importance of software licenses Chapther 14 Development environment briefly mentions how to set up a development environment similar to the one used when making the OOD The next chapters introduce the various software libraries and modules used and explain how they work and how they are configured and used Small excerpts of code will be included when explaining the software but the complete source code will be put in the appendix The last chapter in part three Web interface explains the challenges with developing web pages for an embedded web server the process behind choosing an application framework and how the web Ul is implemented Part two and three will be discussed separately and a conclusion is written separately for hardware and software Part four presents results from testing the web server followed by a discussion and a conclusion for the end result Guidelines and suggestions for further development will
97. ce which allows easy access to the external devices with all the bus logic handled automatically The data bus width can be up to 16 bit wide and the whole width will be used in the OOD application maximising throughput Two parallel memory units will be connected to the PIC24 SRAM for the display buffer and flash which will serve as local storage for GUI graphics Each of the memory devices have their own chip select line as well as a shared read and write line The chip select line is controlled automatically by the EPMP module depending on the address used in a read write operation Configuration Due to the many ways the EPMP module can be configured it can be a bit overwhelming to set it up Luckily most of the configuration is done by a software driver in the lower layers of the graphics library used This will be explained in 4 2 PIC24FJ256DA210 33 chapter 18 1 The first chip select line will be used for the SRAM and the second for the parallel flash The number of address lines needed depend on the memory sizes used The chosen SRAM has an 8 Mbit capacity which will require 19 address lines log 22 19 and the parallel flash 32 Mbit requiring 21 log 222 21 Both memory units are organised as words by 16 bit Integrated graphics controller The PIC24 can be connected directly to a display without the need for a driver The integrated controller is capable of driving 480 x 272 16 bit displays at 60 Hz
98. ch is non zero when all drawing is done Listing 18 3 shows the drawing and touch routines in main GOL messages are passed to all widgets In the case of the aforementioned button the button will change its appearance to a clicked button if the event is a touch event within the button s coordinates In order to do anything useful the event must also trigger an action defined by the developer The function WORD GOLMsgCallback WORD message OBJ_HEADER current bject GOL_MSG xrawMessage is called bv GOL when it is passed messages and the function must be implemented bv the developer The currentObject parameter refers to the affected object and can be used together with the event rawMessage to find out whether a new screen should be loaded or whether to call a function Another function called bv GOL and which must be implemented bv the developer is GOLDrawCallback All widgets are drawn automatically based on their state but any primitive drawing must be done in this function The drawing must be performed in this function in order to not interfere with GOL All the widgets are drawn when this function is called The only exception to only performing drawing operation within GOLDrawCallback is when creating new screens At this moment all widgets should be destroyed and it is not possible 18 2 USING THE GRAPHICS LIBRARY 127 to interfere with GOL Fonts and other resources In order to draw strings on the display
99. ck frequency that can be used in this setup is 20 MHz as found by testing in 66 p 81 82 resulting in a baud rate generator value of 1 37 equation 23 1 The slower start up SPI clock rate value is left as its default value 64 resulting in a clock frequency of 62 kHz ood pic32eth X fatFS mmcPIC32Config h Port controls platform dependent define CS_SETOUT TRISDbits TRISD9 0 define CS_LOW GLATDCER ASEOS define CS_HIGH LATDSET 1 lt lt 9 SPI hardware module used define SPIBRG SPI1BRG define SPIBUF SPI1BUF define SPISTATbits SPIISTATbits define SPI_CHANNEL SPI_CHANNEL1 define SPICONbits SPIICONbits Set slow clock 100k 400k define FCLK_SLOW SPIBRG 64 Set fast clock depends on the CSD define FCLK_FAST SPIBRG 1 Code listing 15 3 FatFS I O layer configuration Modifications to the I O layer implementation A few modifications has been made to the I O layer implementation in order to fit the OOD application An issue with the original implementation was its dependency of the core timer In order to facilitate timeouts on I O operations the I O layer uses the core timer to cause interrupts every millisecond to decrement two timer variables In order to do so the core timer value is reset for every interrupt This will not work if other software modules depend on the core timer not to be reset Since the TCP IP stack s MAC layer module uses the core
100. common 57 so a plug in is needed to provide a comfortable way to select dates and times 23 6 ENCODING CONSIDERATIONS AND BILINGUAL SUPPORT 183 Several plug ins were considered but few were free with suitable licenses small and ran well on the Android test phone The winner was DateBox which provides a series of input widgets that are easy to use on both small displays and desktop computers with or without touch The code size is 24 kB for the core module Figure 23 8 shows the time input pop up helper which has a design similar to that found on Android iOS systems Remaining menus The remaining menus illustrated in figure 23 2 are not yet implemented due to lack of time 23 6 Encoding considerations and bilingual support The preferred encoding for the world wide web is UTF 8 It is also used by jQuery AJAX and expects the backend to handle it There is no problem for the software in the PIC32 to handle UTF 8 there is no string manipulation code having trouble with multi byte sequences the problem lies in the PIC24 with the GUI library string and fonts The graphics library is not directly compatible with UTF 8 This problem has not been given much attention due to the limited time spent on the GUI part of the project The internationalisation support or rather dual language support is only partly implemented Appointments and availabilities are stored in file with strings in two languages but the web UI is only given the
101. cs The main tasks will be to e Evaluate the already suggested design and make necessary changes e Design and implement the necessary specialised hardware e Evaluate hardware e As available time permits develop software that will fulfill selected use cases and requirements in the design e Evaluate the usability and stability of a TCP IP stack with SSL TLS on a resource constrained microcontroller system e Evaluate the system as a whole e Make a description of how the work should be continued The work shall be undertaken with continuation by others in mind Supervisor Associate professor Amund Skavhaug Department of Engineering Cybernetics Summary In some office environments it is natural to visit someone in their office without having an appointment In such cases it can be frustrating to find someone to be unexpectedly absent without any information about why and for how long This thesis presents a solution to this problem with a device mounted on the office occupant s door giving guests information about his or her absence The device has a large display and is remote controlled so that the information can be kept up to date at all times The motivation behind creating this device comes from experiencing the problem first hand As a student it can be challenging to guess the right time to visit one s supervisor s office to find the person present With the presented system students will no longer have to continu ously vi
102. d The milling machine used had some alignment issues when the PCB is turned causing some of the vias to come in contact with neighbouring traces This was fixed by trimming the vias with a scalpel Figure 7 5a on page 55 shows that the pin order on J3 was mistakingly reversed which was fixed by soldering a series of short wires between the connector pins and PCB pads This issue is fixed in the revision shown in figure 7 4b and the circuit diagram in the appendix Apart from this minor flaw the adapter works perfectly and the LED driver works as expected 7 3 SRAM The SRAM chosen for the display buffer must fulfill two requirements 1 It must be large enough to contain at least twice the storage needed to store all pixel data 2 It must be fast enough in order to avoid flicker on screen during updates 1 is easy to calculate whd 2 8 Here w is the width in pixels 480 h height in pixels 272 and d colour depth 16 The result is ne 480 282 16 8 A minimum of 512 kB 4 Mbit is required The required access time is more difficult to calculate since the overhead in the software is not known However the PIC24FJ256DA210 development board manual states that a SRAM with access time of 55 ns should be more than enough for a quarter video graphics array QVGA display 33 p 43 The SRAM chosen is a RILVO816ASB 5SI with 8 Mbit capacity and 55 ns access time The extra capacity is chosen for experimental reasons mainly in
103. d encoding range can be selected as shown in figure 18 3 on the previous page If space allows it it is recommended to start from character 0 This will include a lot of unprintable characters in a range but it makes the font compatible with ASCII which eliminates the need to convert characters GRC also provides methods for converting images to a raw format suited for the graphics library Note that this is not the only way to display images Several image encoders are supplied with the library and these can be used to convert and display uploaded images from the owner in the web Ul If any of the graphics resources are to be stored on an external memory not in program flash memory the function ExternalMemoryCallback must be implemented and supplied with code to retrieve resources based on the arguments provided to the function 18 3 Using a state machine with GOL The graphics library does not provide any mechanisms to switch between pages in a GUI It does however suggest a technique that involves manipulating the global widget list illustrated in figure 18 2 directly 45 p 75 The global pointer pGolObjects is used by GOL to access the start of the widget list This pointer can be used to point at different lists each making up a page Although this method could work it will not be used in the OOD Keeping all widgets for all pages on the heap can exhaust the heap memory so only widgets for the current page will be ke
104. d into a normal desktop computer with an adapter Files can be accessed effortlessly like on any other memory card thanks to using a common file system SD cards support two transfer modes SD mode and SPI mode Both methods are to a certain degree documented in a stripped down specification paper available from the SD Association 13 The SPI mode provides a simple interface to a SD card and is widely used in embedded hobby projects Using SPI will put limits on the maximum read and write speed but it will be preferred due to its simplicity Figure and table 6 1 on the previous page shows the pin out on a microSD card and which pins are needed for SPI interfacing The details of the communication protocol will not discussed in this thesis A disadvantage of using a SD card is the licensing requirements demanded by the SD Association If the OOD will be interoperable with SD cards a license agreement must be signed and annual fees of at least 1000 USD must be paid to the SD Association 6 Although there are many claims that licensing is not required when using SPI communication only no sources has been found that can confirm this If it is indeed required to pay fees in the order of thousands of dollars annually the microSD card should be replaced with alternative memory in a production version of the OOD For now however the microSD card will be used for its important removable feature Necessary connections Figure 6 2 on the faci
105. d slot circuit diagram nenn 47 Parallel flash circuit diagram 2 Con nommen 48 PCIe x4 PCB connector 2 2 2 2 EEE 50 LED driver schematic 2 22 2 Enno 51 Signal lines between the display and the PIC24 microcontroller 52 xili xiv 8 1 9 1 10 1 10 2 10 3 10 4 10 5 10 6 10 7 10 8 10 9 11 1 11 2 18 1 18 2 18 3 18 4 20 1 20 2 20 3 20 4 20 5 LIST OF FIGURES Display to development board adapter 54 Milled PCB with components and display fitted 55 SRAM circuit diagram a ai ee 56 How double buffering works onen 58 Display s position and cable attachment 59 Inrush current limiter circuit diagram 62 The PN532 bo rd u 2 4 2 i pa ao GS Gents a Wu ae Siete eke begs 8S 65 Suggested component placement 2 o o o 69 The finished PCB design 2 o on nn 70 Close up of the EPMP signals in the PCB design 71 Close up of the Ethernet signals in the PCB design 72 Close up of the PIC24 TQFP pad pitch 2 2 2 2 0 73 PCB from the manufacturer 2 2 2 2 o 74 The assembled OOD prototype upper side 75 Inrush current limiter fix nn 76 DANS 720 crystal iR 28 4 2er in l nnd 76 The incorrect placement of the large components 79 0402 resistor footprint and resistor ooo 81 OOD software architecture 22 2 on nn 87
106. d usefulness of some of the functions are limited The PIC24 FC library for instance is cumbersome to use and is just a very thin wrapper around register manipulation The PIC32 peripheral libraries in general seem to be more well written and useful The peripheral libraries are used whenever possible mainly because it is expected the manufacturer knows best how to correctly initialise and use hardware modules 14 2 Setting up a local network There are a number of good reasons for setting up a local network when developing on the OOD 94 CHAPTER 14 DEVELOPMENT ENVIRONMENT e The network can be configured and adjusted whenever needed This is useful for ruling out sources of errors testing network configuration on the OOD and in general prepare the OOD for a range of different network environments e Reduce network traffic both to and from the OOD If the TCP IP stack is misconfigured it may harm slow down the network it is connected to By removing all traffic and broadcasting it can be made sure that the OOD works perfectly in a two node network before testing it in a realistic network scenario e Logging network traffic with tools such as Wireshark becomes a lot easier when it is not necessary to filter out traffic from other devices on the network The following will explain how to mirror the set up used when working with the OOD An USB Ethernet dongle was used to make a completely separate network with a Linux machine hos
107. dars which allows the owner to use appointments defined in a calendar elsewhere Figure 23 3 shows a test using FullCalendar with a single Test appointment and a selection ready to generate a pop up asking for appointment details today lt gt Jul 1 7 2013 day week month Mon 7 1 Tue7 2 Wed7 3 Thu7 4 Fri 7 5 Sat 7 6 Sun 7 7 U D 4pm 18 22 Test 5pm 6pm 7pm Figure 23 3 Interactive calendar for adding appointments The calendar has shown to be a bit cumbersome to use on touch devices and no good alternatives have been found The solution is to add a secondary much simpler interface for managing appointments It will consist of a form for editing the appointment details and touch friendly pop up date and time selectors The calendar can be used by the owner when he has access to desktop computer and the form when on a mobile device Time did unfortunately not permit implementing the calendar menu Inttp arshaw com fullcalendar 178 CHAPTER 23 WEB INTERFACE Configuration Availabilities When making appointments the owner uses a selection of previosly defined availabiliy types to represent his absence presence The format of an availability was described in chapter 19 1 it consists of one of the three base types available unavailable or unknown is represented by a colour and has a title and a description It also contains an ID used by appointments to refer to it Back Configure availabilitie
108. de web or to the public after closing hours the public part of the web interface can be disabled Instead of disabling the public interface access can be limited to specific IP address ranges for example only to machines and mobile devices on the premises 23 1 Limitations and considerations Developing web pages that will run on a simple embedded web server is challenging Web servers normally run on specialised hardware and are capable of handling many thousand requests simultaneously The OOD s web server will never match the performance that of a computer but serving a web interface for the owner is well within the capabilities of the selected hardware and software When it comes to serving a public interface the challenge is to serve a potential large number of users simultaneously The number of clients that can be served at a time depends solely on RAM Each socket is pre allocated on the stack and each socket also needs to be able to have files opened which in turn requires pre allocated buffers on the stack The number of expected clients needs to be determined and chosen at compile time Care must be taken in not allocating too many sockets since only one can be handled at a time Too many open connections will increase the processing time of all the pending requests 169 170 CHAPTER 23 WEB INTERFACE POST sitePOST html Request data related to site Execute callback for requestResponse Print contents of socket specif
109. ders to the client After sending the headers the body is sent which in its simplest case is the contents of the requested file byte by byte However the HTTP server may also call callbacks and mix the output from these functions with the contents of the requested file This will be explained in a later section about dynamic variables Lastly when all data has been transmitted to the client the server terminates the connection Due to the limited amount of RAM the HTTP server cannot afford to keep any connections alive as a normal web server might do 68 p 702 FatFS support Microchip s simple file system MPFS2 is tailored for the HTTP server Using a file system like FAT requires a lot of changes to the HTTP server code but fortunately Microchip includes a version of the web server ported to their own FAT file system implementation MDD The FatFS adaptation is based on this version of the HTTP server the file HTTP2 MDD c found in the TCPIP DEMO APP MDD folder of the MAL and the HTT2 h header file found in the library include directory When Microchip added support for MDD they kept the support for MPFS2 interchangeable by using different symbol definitions in TCPIPConfig h This design choice has been kept intact when FatFS support was added so that in case these changes ever were to be published it would be easy to incorporate them in the full featured stack implementation By excessive use of preprocessor macros the c
110. digit integer filenames All month directories contains files with similar 13 74 75 76 ce 78 79 80 81 82 83 84 85 86 87 88 89 go 91 92 93 94 95 96 97 98 99 100 101 102 103 104 19 2 FILE STRUCTURE 133 ood pic32eth X calendar calendar h struct appointment uinti6 t appointmentID uinti6 t availabilitvID char title 2 char description 2 1 F struct __attribute__ packed calEntrySettings unsigned int titleVisibleWeb 1 unsigned int titleVisibleDisplay als unsigned int descVisibleWeb 3 alg unsigned int descVisibleDisplay peaks unsigned int lastsForever 8 als unsigned int RESERVED 3 dE struct calEntry struct timestamp start struct timestamp end struct calEntrySettings settings struct appointment appointment de struct calDay uint8_t dayNumber uint8_t numEntries struct calEntry entries de Code listing 19 2 Appointment and calendar day objects naming containing serialised calendar day objects calDay see listing 19 2 The system is made robust so that if a clean memory card is inserted the necessary directory structure is created automatically 134 CHAPTER 19 CALENDAR AND AVAILABILITIES 19 3 Real time clock and calendar A separate submodule named dateTime provides methods for retrieving and setting date and time It uses the RTCC to keep time simple network time protocol SNTP to set time and standard C libraries to convert time formats Microchip
111. dule into three layers the respective layers can more easily be replaced it makes debugging and developing easier and it makes it easier to reuse code the EC driver in particular may prove useful in other cases 16 1 IC driver Microchip provides an I C driver module in its peripheral library It is however merely a simple wrapper around register manipulation and it requires a lot of manual intervention and function calls Among others it is necessary for the user to manually acknowledge data 8 An I C software driver module was made from scratch in order to make 12C communication less cumbersome The goals of making a driver were to eliminate unnecessary low level calls for ordinary tasks improve error handling and provide good documentation for the module The module is implemented using a interrupt driven state machine Since the PIC24 only provides a single interrupt for 12C the reason for the interrupt needs to be determined for every interrupt 27 p 13 The work performed in the interrupt routine depends on the current state The following are the states used in the module I2C_STATE_ idle Driver is idle I2C_STATE_sendingStart Driver is sending start condition I2C_STATE_dataTX Driver is sending data from the TX RX buffer 12C_STATE_sendingRestart Driver is sending repeated start condition 12C_STATE_sendingStop Driver is sending stop condition I2C STATE dataRX Driver is receiving data and writing to the TX RX buffer 16 2 F
112. e an a 4 T S8SA u un e gt CETTE TTT k l a B2 Figure 10 6 PCB from the manufacturer problems were encountered which will be discussed in the following sections Inrush current limiter problem Testing soon revealed that the inrush current limiter did not work and investigation revealed that an embarrassing design flaw in the circuit was to blame the MOSFET was fed a raw 47 V to its gate instead of a much lower threshold voltage of 1 3 V This was remedied by making a voltage divider using the original 100 kQ resistor and a 6190 Q resistor as illustrated in figure 10 8 on page 76 10 7 TESTING AND VERIFICATION 75 xi Y78129 29143162 wee or ES amp l ee O R27 oT Rie ci3 C14 ver 110 c26 DT R39 c11 ee er Wi 36 535 R17 gt c12 Andreas Misje ma 4 G37C46 2013 csa Figure 10 7 The assembled OOD prototype upper side display currently not present LAN8720 crystal problem When the Ethernet transceiver circuit was soldered into place and connected to a network interface the expected result was to see the link LED light up Instead the link and 100 Mbit LEDs displayed erratic behaviour The problem was hard to find but it was eventually discovered that the 25 MHz crystal was connected incorrectly The incorrect pins were chosen when making the crystal part in Eagle This was remedied by using a small metal bridge as seen in figure 10 9 on the next page 76 CHAPTER 10 PCB DESIGN AND ASSEM
113. e interfaced with other devices by using a public application programming interface API A good candidate for this is the hall monitors found at ITK and the Department of Telematics ITEM They are used to show a list of the employees in the building their contact info and where their offices are on the premises It would be useful to improve these monitors by including information about the employees presence The following examples and scenarios from 66 illustrate how the OOD can be used The office worker is in a meeting that lasts longer than anticipated Instead of having to receive numerous calls from people wondering about his or her whereabouts the office worker can discretely update the message on the display remotely with a smartphone application or a web interface 2 2 MAIN COMPONENTS 11 e An unforeseen incident prevents the office worker from going to work In a matter of seconds the office worker can update the out of office display with the duration of the absence and a reason e The office worker is in a rush and must leave the office quickly There is no time to leave a detailed message but by flicking an ID card in front of the OOD a generic absence status will be activated This action takes no more than a second ensuring that the office worker always keeps his or her status updated regardless of the haste e A visitor finds out that the office worker is out of office The visitor may have a delivery a me
114. e is free of charge or affordable is compatible with the microcontroller and has a small code footprint It is not found necessary to include a RTOS on either of the microcontrollers The main reasons for this are e There are no time critical tasks in either systems The TCP IP stack can handle delays well and the display is kept refreshed by hardware e The problems connected to sharing data between threads and needs for mutual exclusion locks are eliminated Debugging is simpler e The libraries used are built for cooperative multitasking They give no guarantees or information about the run time of their tasks but testing has not revealed any excessively long run times 13 2 CHOOSING LIBRARIES 89 e Code space is saved and there is no need to spend time on configuring the OS and threads 13 2 Choosing libraries The process of selecting the necessary software libraries has been simple and short When it comes to GUI and graphics libraries there are almost no other realistic alternatives than the ones provided by Microchip Microchip provides drivers for the integrated graphics controller in the PIC24 a primitive drawing layer that uses the device driver and a third layer which provides objects widgets as buttons input fields and the like An alternative to using the whole graphics stack is to only use the driver from Microchip and add support for a third party layer on top or develop one from scratch However these options a
115. e NFC reader In order to keep the OOD small the smallest footprints are chosen whenever possible All resistors are 0402 unless they need to withstand higher stress All capacitors are 0402 with a few exceptions where higher voltages than 3 3 V are expected PoE and inrush current limiter circuit The trace widths in the PCB are kept as small as possible while still allowing sufficient current Distance between tracks are always kept as large as possible and greater attention is given for the higher voltage traces PoE 10 3 Placing components Placing the components is a difficult process due to the many requirements and dependencies The following requirements need to be taken into consideration 1 The tall components shall be at the lower section of the PCB 2 The tall components need to be as close together within the width of the PCB reducing the height of the occupied area as much as possible 10 3 PLACING COMPONENTS 69 YA192810 Mmmm Display connectors gt Es Display cable ducts NFC UART t Figure 10 1 Suggested component placement mirrored text indicate components on the opposite side 3 The display must be placed on the same side as the tall components 4 The microSD card slot must be placed so that the card is easily accessed preferable placed at the edge 5 The pin headers for ICSP and debug UART need room for cable insertion and the NFC UART needs room for cables to be permanent
116. e OOD application will gradually be introduced in the following chapters The full source can be found in appendix A As mentioned earlier the MAL source code along with its modifications cannot be redistributed due to the license restrictions In order to include the MAL code changes in the thesis the distribution restriction is circumvented by adding patches for the original code In order to prepare the OOD programming projects the MAL needs to be downloaded and extracted and the patch added as described in appendix A 1 14 2 SETTING UP A LOCAL NETWORK 93 ta Microchip a Help DOCUMENTATION ta Include nl SOURCE CODE Graphics i header h files l Categorv n TCPIP Graphics SOURCE CODE all other files Category n TCPIP Graphics i DEMO PROJECTS Category n Figure 14 2 MAL file structure XC32 and XC16 peripheral libraries Microchip provides software libraries for both their 16 and 32 bit microcon trollers that eliminates the need write drivers for all the microcontroller periph eral modules These libraries are called peripheal libraries and are found in the directories where the compilers are installed on the system With these libraries there is ideally no need to write code for initialising and using UART SPI EC interrupts and DMA just to list some examples However upon reading the documentation and source code of some of these implementations it appears that the code quality an
117. e TCP IP stack compile with a 2048 key the file SSLClientSize h needs to be modified Use the patch mal v2013 02 15 patch in appendix A 1 to fix this 20 7 SNTP client With the lack of a battery the OOD loses track of time when the power is lost It is important for the OOD to know time in order to change availability statuses based on the appointments added by the owner Instead of relying on the owner to manually set the time SNTP is used to synchronise the RTCC with an accurate clock source SNTP is a simplification of the NTP protocol and was first defined in RFC 1361 16 A simple request is sent to a NTP pool server and the response contains a timestamp with a 32 bit seconds part and a 32 bits fraction part relative to Jan 1st 1900 at 00 00 16 p 3 Microchip s SNTP implementation does not use the full precisision which is 200 picoseconds but rounds up to the closest second This is perfectly adequate since the smallest time fraction RTCC supports is second Modifications The original SNTP implementation stores the retrieved timestamp and keeps it valid by adding the time past since its retrieval using the TCP IP stack s Tick module The changes made to the original code is summarised in the following list e The NTP pool server string which was previously defined as a constant can now be accessed and modified using set and get functions so that the user can choose which pool server to use This will allo
118. e grafiske grenses nitt pa en 16 bits mikrokontroller men ikke uten utfordringer Det er tungvint utvikle og byr p utfordringer hva ang r skrifttyper og tegnsett Resultater fra tester av vevtjeneren sammen med et FAT32 filsystem og et microSD minnekort viser at systemet er i stand til vi levere data med en hastighet p 550 kB s Dette var nok for kj re et enkeltbrukervevgrensesnitt men hastigheten er ikke bra nok for a levere nettsider til mer enn en handfull klienter om gangen Mikrokon trolleren klarte a tilby SSL med 2048 bit store ngkler men det tok sa lenge som tre sekunder dekode RSA HTTPS hastigheten l stabilt pa 317 kB s ved bruk av 128 bit ARCFOUR noe som er marginalt raskt nok for 4 kunne kryptere all HTTP trafikk Resultatene viser at mikrokontrollerne lever akkurat gode nok resul tater for form let men det b r vurderes velge en embedded Linux plattform for videre arbeid Contents Contents vii List of Figures xiii List of Tables xvii List of Acronyms xxiii I Introduction 1 1 Introduction 3 KI B ckgr nd 23 St 2a whe a ae de 4 Choice of architecture 2 22 2 on nn 5 1D Scope Tana 4 bale arte Pee ek ee 6 1 3 Outline of the thesis 2 2 2 Comm e e 6 2 Specification and system design 9 2 1 Areas of application m nn 10 2 2 Main components 2 ua a a a 11 Display and GUL 22 es Oa dc ada A 11 Network connection and web server 2 2222 13
119. e time since the sockets are statically allocated Transmit and reception buffer sizes must also be chosen It is difficult to estimate how many concurrent web clients the system should handle Among other things it is difficult to know beforehand how many users that will use the public web UI The traffic also very much depends on whether the network the OOD is located on is restricted or whether it is fully accessible from the Internet Until the device has been tested in its intended environment the number of concurrent users has to be set to a reasonable number The chosen value is 10 which still leaves free RAM and allows for later increase The number of simultaneous SSL connections allowed has been limited to a low number of two which should pose no problem since only the owner is allowed access to the administration pages Socket buffers are set on two layers The MAC sublayer needs buffers to store data that will be received and sent from both the TCP and UDP protocols and TCP needs socket buffers for all applications using TCP The optimal MAC buffer configuration was found by adjusting the number of RX and TX buffers during a series of tests with 10 concurrent HTTP connections They were lowered until no decline in performance was observed resulting in 3 TX buffers and 7 RX buffers The buffers needs to be large enough to contain the largest expected Ethernet frame otherwise the whole packet could be dropped According to the standards
120. e variable name must start with inc followed by the path There is no need to implement a callback function for this This feature is used in the HTML files in the web UI in order to inlude code common for all files Table 20 2 Format of FileRcrd bin Data type offset Description UInt32 Number of files with dynamic variables UInt16 Hash of file name for fast search look up UInt32 Offset for record in DynRerd bin UInt32 Number of dynamic variables in the file Table 20 3 Format of DynRerd bin Data type offset Description UInt32 Length of record UInt16 Flags UInt32 Offset in page where it used UInt32 Callback ID The web server uses knowledge stored in two binary files FileRerd bin and DynRerd bin to find out which files contain dynamic variables their offsets and IDs that determine which callbacks to call Table 20 2 to 20 3 on the current page shows the format of these files based on reverse engineering The first four bytes of FileRcrd bin contains the number of files that use dynamic variables The rest of the file contain records with the format shown in table 20 2 The hash is computed from the file name and stored in a 16 bit variable and is used to compare file names and their records in the FileRerd bin DynRerd bin contains information about the offset of the variable name in the HTML file and the ID 1Not part of record repeating pattern 148 CHAPTER 20 TCP IP STACK of the ca
121. eTime module see chapter 19 3 and the peripheral library s RTCC functions If correct timestamps were to be ignored get_fattime must still be implemented but it can return a dummy value ood pic32eth X fatFS fatTime c DWORD get_fattime void rtccTime t rtccDate d RtccGetTimeDate amp t amp d DWORD fatTime fatTime BCDToDec d year 20 lt lt 25 fatTime BCDToDec d mon lt lt 21 fatTime BCDToDec d mday lt lt 16 fatTime BCDToDec t hour lt lt 11 fatTime BCDToDec t min lt lt 5 fatTime BCDToDec t sec 2 return fatTime Code listing 15 2 Function providing FatFS with a timestamp The last thing needed to be done before compiling FatFS is configuring the I O library specifically setting which SPI hardware module is used setting the wanted SPI clock frequency and tell the library which pin is used as chip select vos DN fF 10 41 12 13 14 15 16 17 18 19 102 CHAPTER 15 FILE SYSTEM These configuration definitions have been moved from mmcPIC32 c to a separate file mmePIC32Config h in order to separate configuration and implementation Listing 15 3 shows the contents of the file The SPI module used is 1 and the chosen I O pin for SD SPI chip select is RD9 see pin allocation table in appendix B The original commands used to manipulate the chip select pin has been replaced by their atomic counterparts LATxCLR and LATxSET The maximum SPI clo
122. ecommended minimum connections for PIC32 from 39 p 44 The absolute minimum of connections for the PIC32 is very similar to those of the PIC24 Figure 4 5 shows the recommendations from the datasheet As with the PIC24 a 8 MHz crystal was used but the PIC32 can run at 80 MHz using correct PLL prescaler settings PIC32 s ICSP lines follow the same circuit diagram as PIC24 The PIC32 is given a second crystal for the real time calendar clock RTCC module running on 32 768 Hz as seen in sheet 5 in appendix C 4 4 Erratas It is a must to always study the erratas of hardware components and Microchip s microcontrollers are no exceptions The errata for the PIC24 contains only a few issues non of which are considered to affect the OOD application 48 The PIC32 however has an errata with surprisingly many issues Fortunately none of the listed issues should affect the intended use of the microcontroller Ethernet In 66 three different Ethernet transceivers were tested ENC28J60 ENC624J600 and DP83848C The ENC28J60 only supports SPI which limits throughput whereas ENC624J600 supports various parallel bus communication methods and DP83848C supports MIT and RMII ENC624J600 is interesting as it implements the MAC sublayer making it not only a transceiver but an Ethernet controller It also includes a large 24 kB RX TX buffer and hardware support for several cryptographic algorithms including RSA AES MD5 and SHA 1 31 This co
123. ee for LEN and get fattime for time All the former functions are trivially implemented defined as shown in listing 15 1 The memory allocation functions from the XC32 compiler s stdlib is used for allocating the LFN working buffers on the heap and all character encoding conversion is effectively ignored These conversion functions may need to be changed for proper internationalisation support but they they can safely be ignored for now ood pic32eth X fatFS ffconf h define ff memalloc size malloc size t size define ff memfree ptr free ptr define ff_wtoupper ch ch define ff_convert ch code ch Code listing 15 1 FatFS user defined memory and conversion functions get_fattime is necessary for FatFS to store correct timestamps on files and directories when they are modified Although not strictly necessary it is a small O AON QQ a 10 12 13 14 15 16 17 18 19 15 1 HOW THE LIBRARY WORKS 101 task to add support for this since the PIC32 s RTCC will be configured and used in the project anyway Having correct timestamps on files makes troubleshooting and developing easier get_fattime returns an unsigned 32 bit integer that stores both date and time in a compact format The format is as follows 31 25 Year from 1980 0 127 24 21 Month 1 12 20 16 Day of month 1 31 15 11 Hour 0 23 10 5 Minute 0 59 4 0 Second 2 0 29 Listing 15 2 shows the implementation based on the dat
124. el bus Data bus 99 PMD3 CN61 RE3 PMD3 Parallel bus Data bus 100 PMD4 CN62 RE4 PMD4 Parallel bus Data bus 3 PMD5 CN63 RE5 PMD5 Parallel bus Data bus 4 SCL3 PMD6 CN64 RE6 PMD6 Parallel bus Data bus 5 SDA3 PMD7 CN65 RE7 PMD7 Parallel bus Data bus 90 PMD8 CN77 RGO PMD8 Parallel bus Data bus 89 PMD9 CN78 RG1 PMD9 Parallel bus Data bus 82 RP20 PMRD CN14 RD5 PMRD Parallel bus Read signal 81 RP25 PMWR CN13 RD4 PMWR Parallel bus Write signal PIC24 pin allocation Pin Functions Function used Purpose Purpose details Alt function Comments Moveable 17 TMS CN33 RAO 38 TCK CN34 RA1 55 VUSB 56 D CN84 RG3 57 D CN83 RG2 58 SCL2 CN35 RA2 Alt Touch I C 60 TDI PMA21 PMA3 2 CN37 RA4 PMA3 61 TDO CN38 RA5 73 SOSCI C3IND CN1 RC13 PIC32 pin allocation Function used P Purpose details Alt function Moveable 13 MCLR Chip program 24 PGEC1 AN1 CN3 RB1 PGEC1 Chip program Yes 25 PGED1 ANO CN2 RBO PGED1 Chip program Yes 12 ERXDV AERXDV ECRSDV AECRSDV SCL4 SDO2 U3TX PMA3 CN10 RG8 ECRSDV Ethernet CRS_DV AECRSDV 71 EMDC AEMDC IC4 PMCS1 PMA14 RD11 EMDC Ethernet MDC AEMDC Yes 68 RTCC EMDIO AEMDIO IC1 RD8 EMDIO Ethernet MDIO AEMDIO Yes 14 ERXCLK AERXCLK EREFCLK AEREFCLK SS2 U6RX U3CTS PMA2 CN11 RG9 EREFCLK Ethernet REFCLK AEREFCLK Yes 41 AN12 ERXDO AECRS PMA11 RB12 ERXDO Ethernet RXDO Yes 42 AN13 ERXD1 AECOL PMA10 RB13 ERXD1 Ethernet RXD1 Yes 35 AN11 ERXERR AETXERR PMA12 RB11 ERXERR Ethernet RXER Yes 88 ETXDO PMD10 RF1 ETXDO Ethernet TXDO Yes 87
125. ello 1 Length 113 Version SSL 3 0 0x0300 gt Random Session ID Length 32 Cipher Suites Length 42 gt Cipher Suites 21 suites Compression Methods Length 1 gt Compression Methods 1 method a Client hello packet with session ID highligheted gt Internet Protocol Version 4 Src 10 10 10 11 10 10 10 11 Dst 10 10 10 10 gt Transmission Control Protocol Src Port https 443 Dst Port 43730 43730 gt 2 Reassembled TCP Segments 79 bytes 9 5 11 74 Y Secure Sockets Layer Y SSLv3 Record Layer Handshake Protocol Server Hello Content Type Handshake 22 Version SSL 3 0 0x0300 Length 74 Y Handshake Protocol Server Hello Handshake Type Server Hello 2 Length 70 Version SSL 3 0 0x0300 gt Random Session ID Length 32 E Suite TLS RSA WITH_RC4_128 MDS En Compression Method null 0 b Server hello packet with session ID highligheted Figure 26 3 Client hello and server hello packets with same session ID 200 CHAPTER 26 TESTING AND RESULTS This may be a natural result of design choices done by the developers of the stack or they may be problems It is not known for certain and in order to provide stable predictable response times the source of these sporadic delays should be investigated 26 2 Display touch and GUI Figure 26 4 GUI main page mock up on development board Due to the problems with the parallel flash it has not been possible to extensively test
126. er good reason to choose FatFS is that it is a stable and maintained software library 54 The software license allows modification and redistribution for both educational and commercial use without any limitations 15 1 How the library works Figure 15 1 on the preceding page shows the architecture of the FatFS library FatFS is only a filesystem and relies on other libraries to perform low level disk I O operations in this case communicate with the microSD card and get the current time from a hardware clock FatFS is hence easily portable but a separate I O library is needed An implementation for PIC32 using SD with SPI at the I O level is available from a Microchip forum thread 44 with an unrestricted license With a few modifications this is the library that will be used for FAT I O operations in the PIC32 Configuring FatFS FatFS can be compiled only with necessary functionality saving program memory Table 15 1 on the next page lists the definitions that can be adjusted in ffconf h along with their meanings The last column indicates which value is chosen for the OOD application Long filename LFN support has been added so that no filenames need to be shortened Since filenames are exposed to the user through the uniform resource locator URL it is not wanted to limit their length to eight characters The code page chosen for LFN is 1252 Latin 1 which supports Scandinavian letters Although the web server only needs read
127. er implementation used in a Microchip product PIC32 GUI Development Board 49 A reference design is borrowed instead of made from scratch so that the adapter can be made as quickly as possible Figure 7 2 shows the circuit diagram of the LED driver The components used and their values are shown in table 7 1 on the following page They were chosen based on recommendations and on reference designs in the MCP1650 datasheet 18 By applying a pulse width modulation PWM signal to the SHDN signal on the MCP1650 the display backlight can be dimmed Display LED backlight driver pl D1 A UDD LED ie GND BKLT_PWM LED GND GND Figure 7 2 LED driver schematic Connecting RGB and control signals The display needs to be connected to the microcontroller with 29 lines disregarding power and LED driving As figure 7 3 on the next page shows 24 of these lines make up the RGB bus and the last five are synchronisation clock and control lines As explained in the display theory in 66 p 49 some of the least significant bit LSB RGB lines are tied to their respective most significant bit MSB line in order to have the 16 bit display controller drive a 24 bit display The resulting colour degradation is not noticeable for the graphics that will be used on the display The effect would be most noticable on colour gradients that have not been converted and modified properly for 16 bits
128. ere e No existing development hardware with Ethernet PoE and display driving capabilities could be found e Making the hardware would make it possible to customise its functionality and physical shape for the OOD application e Making the hardware would be a great opportunity to gain more knowledge in circuit and PCB design The result was overall a success especially given that the goal was only to make a prototype The flaws have been discussed improvements suggested and ideas for further development has been given It has been proved that a two layer design with Ethernet and two memory devices with a large address and data bus was possible and that the freeware ECAD tool Eagle worked well to design such a PCB Before any further development takes place the two layer microcontroller design the PoE power and inrush circuit should be given more attention in order to improve the design and hopefully make it even more compact The prototype was not designed with manufacturing costs in mind so further work should consider moving more components to one side of the PCB in order to limit manufacturing costs for possible mass production Lastly the choice of using microcontrollers and a two layer design should be considered well The complexity and costs of making a multi layer PCB with a chip capable of running a Linux operation system may be manageable at a later time especially by someone with good experience in PCB design 83 Part III
129. ere are a few plug ins that can render 3D models from eagle files Using such a plug in is recommended for any further development using Eagle with components on both sides Another suggested improvement is to use a better 0402 footprint than the one used Eagle s standard 0402 resistor capacitor footprint It was taken for granted that this footprint was perfectly suited but it turned out that the pads were unnecessarily long and the distance between them were excessive See figure 11 2 on the next page for an image of a footprint and an unsoldered resistor leagle3D http www matwei de doku php id en eagle3d eagle3d eagleUP https eagleup wordpress com 11 3 MISSING NFC INTEGRATION 81 Figure 11 2 0402 resistor footprint and resistor For further development the correct crystal and buzzer PWM pin out must be remembered and the voltage divider used to drive the inrush current limiter MOSFET most be included in the design 11 3 Missing NFC integration The main obstacle preventing NFC integration is the display blocking for an antenna placed on the PCB A possible solution is to extend the frame of the OOD and place the antenna around the display Another much preferable solution is to look into technologies that combine capacative touch overlays and NFC antennas A company providing this technology is Cirque with their GlidePoint NFC product 3 Hardware Conclusion The three reasons for making the hardware w
130. follow the process of choosing hardware Figure 4 1 shows a series of different protocols used some which may be less common than others A small introduction to all the protocols used will be given 29 30 CHAPTER 4 MICROCONTROLLERS in the following section 4 1 Communication protocols The following list introduces the protocols and standards used for communication between the devices used in the OOD Inter intergrated circuit 12C A two wire multi master bi directional serial bus It supports transfer rates up to 100 or 400 kbit s in most implementations but the standard also allows up to 1 MBit s with Fast mode Plus and 3 4 Mbit s with High speed mode 52 The bus lines require pull up resistors Serial peripheral interface bus SPI A synchronous full duplex serial data link supporting multiple slaves at the cost of one chip select wire per slave 65 Three other wires are needed regardless of the number of slaves The protocol is not limited to a maximum clock frequency and can therefore allow high throughput if the devices support it Universal asynchronous receiver transmitter UART A two wire full duplex se rial data link often used in conjunction with RS 232 RS 422 and RS 485 Fixed baud rates are used eliminating the need for a clock line 65 Reduced media independent interface RMII An alternative to media indepen dent interface MID using a higher clock frequency and fewer data lines
131. for TCP IP SSL and graphics will also almost certainly reveal unforeseen problems and challenges that may result in redesigns during development and testing The hardware process is stuck with one way arrows for one reason there will simply be no time to make a second prototype The PCB has to work 20 CHAPTER 2 SPECIFICATION AND SYSTEM DESIGN Fix and improve gt Hardware development Embedded software development gt Web UI development Select Design Design PCB Produce PCB and Test and verifv components schematics solder components e A Y Kole A Implement drivers Test drivers on de development kits if possible Hello x world Plan software A Find libraries Develop software Test software and architecture m mM lt b gt and explore their lt gt use drivers test web pages on capabilities o prototvpe ew n dev kits if possible l gt Design menus Find libraries Develop Ul mi and explore their gt Ro capabilities Test device in its intended environment Figure 2 5 The design process Part II Hardware Development boards In the preliminary design 66 the capabilities of the suggested hardware were tested using development boards The three major software libraries used in this thesis FatFS the TCP TP stack and graphics library were tested to ensure they would work on the hardware and their features were explored Development hardware for several Ethernet solutions were also tested
132. g the certificate info and private and public key for RSA used by SSL Provides a few functions that do all the initialisation and periodic work for all the modules in the TCP IP stack Functions for sending and receiving data using TCP and sockets The library s main include header en suring that files are included depending on the stack configuration in TCPIP Config h Contains all the configuration for all the components in the library including which protocols modules to include A module providing functions to mea sure relative time both in very small and very large intervals 20 2 STACK CONFIGURATION 139 UDP c h Functions for sending and receiving UDP data In order to set up the Microchip TCP IP stack according to these needs the necessary files must be included in the build Table 20 1 on page 137 shows the files needed for each component protocol module driver in the stack Any extra files as a result of the modifications done to the TCP IP stack are not listed in the table but they are introduced in the following sections In addition to including files the stack must be configured to use the selected protocols and modules This is done by defining symbols in TCPIPConfig h 20 2 Stack configuration The TCP IP stack requires one file to hold all the configuration which must be provided by the user The file must be named TCPIPConfig h and must be in the include path of the compiler In order to include t
133. glass NHD 4 3 480272EF ATXL CIP define DISP_ORIENTATION 0 define DISP_HOR_RESOLUTION 480 define DISP_VER_RESOLUTION 272 define DISP_DATA_WIDTH 24 define DISP_HOR_PULSE_WIDTH 41 define DISP_HOR_BACK_PORCH 2 define DISP_HOR_FRONT_PORCH 2 define DISP_VER_PULSE_WIDTH 10 define DISP_VER_BACK_PORCH 2 define DISP_VER_FRONT_PORCH 2 define GFX_LCD_TYPE GFX_LCD_ TFT Code listing 18 2 Display and integrated graphics controller configuration Listing 18 2 shows the display configuration including pixel width and height HSYNC and VSYNC pulse width and porches The numbers are fetched from the Newhaven datasheet 67 p 11 Explaining the details of how TFT displays work is not part of the scope of this thesis A few more details are needed that are not listed in listing 18 2 These define the functions used to turn the display on and off or how to dim it See appendix A for the full configuration The configuration of the graphics library is done in GraphicsConfig h This file defines whether double buffering should be used which GOL widgets should 18 2 USING THE GRAPHICS LIBRARY 125 be included what colour depth should be used and what default font and scheme to use GOL schemes will be discussed later 18 2 Using the graphics library When developing graphics application it may be necessary to use functions from all three layers The most useful functions from the driver layer are GetPixel SetPixel and functions for
134. h SSL support Transport layer security is a complex subject and it falls outside of the scope of this thesis to discuss the details and inner workins of SSL TLS The SSL protocol has gone through several versions the last being TLS 1 2 RFC 5246 156 CHAPTER 20 TCP IP STACK Source Settings Start With Webpage Directory 1 Source Directory ood pic32eth Xjhtmi Browse Processing Options gt Output BIN Image PIC18 PIC32 Image PIC24 dsPIC Image MDD Processing Output Files 3 Project Directory ood pic32eth x Date June 26 2012 Generate Version MPFS 2 2 1 Generator Idle Figure 20 5 The MPFS2 HTML converter The version used in this thesis is SSL 3 0 which as of 2011 is still the most widely used version 68 p 872 Microchip s SSL3 implementation supports only one cipher suite RSA for key exchange and authentication RC4 ARCFOUR 128 bits for message stream encryption and MD5 for message authentication RSA keys up to 2048 bits are supported and the goal is to use the highest key size supported that still provides acceptable performance From a security standpoint it is recommended to use key sizes over 1024 bit 23 This may seem unnecessarily strict for a simple embedded system and there are probably many vulnerabilities in the stack that are easier to exploit than attacking SSL but it is a great way to push the limits and see how well cryptographic fu
135. hanges do not add any extra code if not used but it severely reduces readability For this reason it is recommended to strip away any MPFS2 and MDD related code for any further development since support for these file system implementations are not needed The files FileSystem c and FileSystem h constitutes a layer between the HTTP server and the chosen file system implementation Based on defines in TCPIPConfig h the correct function is used for various I O operations as demonstrated in listing 20 1 on the next page This layer is unnecessary if no support is needed for multiple file system implementations and can be removed in order to save some code space The following lists some of the necessary changes for making FatFS working with the web server Two heap allocated strings removed Two pointers tempPtr and dummyPtr note the good variable names are used to modify the file path from the query changing to AN FatFS can handle the original UNIX style path name format so the string manipulation and hence the two pointers are no longer needed This also 236 237 238 239 240 241 242 243 244 245 20 5 HTTP SERVER 145 MAL TCPIP Stack FileSystem c int FileEOF FILE_HANDLE stream if defined STACK_USE_MPFS2 return MPFSGetBytesRem stream elif defined STACK_USE_MDD return FSfeof stream telif defined STACK USE FATFS return f eof stream endif Code listing 20 1 Choosing function based o
136. he analog power is provided by VDD run through a ferrite bead All capacitors value are based on recommondations in 51 Figure 5 2 shows the circuit diagram the complete diagram is in sheet 6 in appendix C 5 3 CONNECTOR AND TRANSFORMERS 41 NE R24 100M_LED 101 10k9 109 me GND RXD1 Rs 109 TXD TXDO R26 TXD1 TXD1 RXER TXEN 182 RXD MODE RXD1 MODE1 RXER PHYADO REFCLK_ RES to 339 MDC R31 NINT REFCLKO CRS_DU CI CRS DU MODE 109 4 XTAL1 CLKIN 5 XTAL2 NRST E s EJE gt N R32 UDD C34 C32 R34 MDIO YODO pa 10k 1 10L GND GND Figure 5 3 LAN8720 circuit diagram RMII termination LEDs and crystal LEDs RMII and crystal All the RMII receive lines are given a 10 Q series termination as suggested in 51 The LED1 pin which indicate link status drives a LED directly but the LED2 pin which indicate 100 Mbit status activity is pulled to ground with a 10 kQ resistor This makes the LAN8720 output a 50 MHz reference clock on the REFCLKO pin generated from the 25 MHz crystal nRST is tied to VDD with a 10 kQ resistor MDIO is tied to VDD with a 1 5 kQ resistor and REFCLKO has a 33 2 series termination all as recommended in the very helpful Schematic Checklist documentation 51 The resulting diagram is shown in figure 5 3 5 3 Connector and transformers A connector and a series of transformers are needed to complete the Ethernet circuit In 66 an 8P
137. he contents of the files listed in table 20 1 definitions of the form STACK USE DHCP CLIENT must be present in the configuration file This makes it possible to swiftly enable and disable major parts of the stack The configuration file also has to define socket buffer sizes and other protocol and application specific settings The complete configuration is listed in appendix A and the protocol specific configuration will be explained in the following sections Setting MAC and IP addresses The stack relies on a global object AppConfig to contain MAC address IP address and subnet mask among other things The PIC32 microcontroller comes with its own MAC address and order to use it the special address 00 04 A3 00 00 00 must be used 47 p 153 The stack will later recognise this special address and query the hardware for the correct MAC address and use it when necessary The remaining settings are loaded from file as other system settings 20 3 Using the stack The stack is initialised by calling the two functions void TickInit and void StackInit 140 CHAPTER 20 TCP IP STACK in that order Based on the defines in TCPIPConfig h the initialisation routines for the required protocols and modules are called in turn After initialisation the functions void StackTask and void StackApplications must be called regularly StackTask will perform lower level tasks like receiving and transmitting packets while StackApp
138. he current architecture is chosen for further work the following are ideas and suggestions for further development e Resolve parallel flash issues so that GUI development can be started on the PIC24 e Achieve greater web server throughput e Decide how to handle encoding User supplied text from the web UI come in UTF 8 Unicode and will ultimately be displayed in the GUI which uses 16 bit character storage and needs preconfigured character ranges in fonts e Finish the state machine framework for switching screens in the GUI and implement screens 27 4 FURTHER WORK 203 Finish web UI with great attention to a good calendar implementation Put the inter microcontroller communication protocol in use and use it pass data Use image encoders in the graphics librarv to convert user uploaded images to a raw bitmap format for the graphics library Explore bootloader implementations and find a good solution that can flash both microcontrollers for instance use the PIC32 to flash PIC24 using SPI Conclusion What started as an idea hoping to solve an everyday problem at the university has been made into hardware and software almost ready to provide a working solution With the help of further development the out ofoffice display will hopefully soon be found on office doors helping students finding out when and where to get in touch with their professors for guidance The work presented in this thesis has taken the reader th
139. hip s own file system MPFS2 a lightweight read only file system that can reside on both external memory and internal flash memory 47 p 276 Another implementation that supports Microchip s own FAT file system MDD is also provided with MAL as a demo This file system was superseded by FatFS performance as mentioned in chapter 15 Since no port of the web server using FatFS could be found it had to be made The implementation will be discussed in section 20 5 Support for FatFS is the biggest modification Among other small changes are improved multi client support in the HTTP server IP address based access 20 5 HTTP SERVER 141 control lists ACLs and support for updating the RTCC using SNTP These changes will be described in the following sections 20 5 HTTP server The HTTP server is the most important part of the PIC32 microcontroller It serves the web Ul which is the main configuration interface supporting more controls and features than the display GUI Most importantly it enables remote control of the OOD which sets it apart from sticky notes and other primitive out of office notification methods Implementing a web server on embedded hardware comes with a series of challenges The main challenge is the limited memory Since the Ethernet transceiver does not have any integrated buffers all transmit and receive buffers need to be allocated in the microcontroller memory This puts restrictions on how many client
140. ibutes can be parsed and used to build the necessary HTML that the browser needs This is done automatically by load onload events which jQuery Mobile attaches its own code to when it is loaded from the script tags Any JavaScript user code that should load when the page is loaded need to be called in the event pagebeforeshow like mainPage on pagebeforeshow function event Custom JavaScript code will be used in the web UI to check form data trigger pop up messages query the server for data and add new data among other things It has not been the intention to write web pages that work correctly without JavaScript the user may disable JavaScript in his browser if he so wishes because jQuery Mobile would not work without it Although forms are checked for incorrect data before data is sent to the server great care is taken in the server to check the data not relying on the sender to send correct data 176 CHAPTER 23 WEB INTERFACE MAIN PAGE MED Name title portrait Current availabilitv Future availabilitv calendar Authenticated Calendar change appointments Configure tvpes of availabilitv Set name and title Set time and date configure SNTP Configure network settings Configure network ACL Configure user names and passwords Configure displav GUI functionalitv Configure public web page Figure 23 2 Web UI menu structure Web interface menu structure The web UI will consist of t
141. ic variable 0 0 0 Map file name in URL to 0 appropriate callback function 0 0 0 O Serve HTML body Handle request Prepare data Save data in socket specific storage Figure 23 1 How a request from the client is handled in the web server The web server as discussed in chapter 20 5 supports the use of basic access authentication POST and GET cookies and dynamic variables Since there is no support for a scripting language POST processing and dynamic variables will have to be used to implement a backend system The implementation is shown in figure 23 1 The steps shown are 1 The client requests data by sending a POST request The file name in the URL is important as it will determine which callback function that will handle the POST request 2 The extension mentioned in chapter 20 5 will use the file name in the request to look in an array to find the correct POST processing function to call 3 The POST processor will fetch and parse name and value pairs and prepare the requested data The data will be stored in a socket specific variable to 23 2 FRONTEND 171 ensure thread safety 4 After the POST callback handler is called the HTTP headers and body will be served The contents of the HTML page in the request usually only contains one dynamic variable which will serve the requested data prepared in step 3 When serving the body the dynamic variable callback will be called 5 The dynamic variable callback
142. ied If the address matches a range with pass set to true it will be allowed If the address is not within any range the defaultPass variable will settle the faith of the connection ood pic32eth X ipACL h struct ipACLRuleSet struct ipACLRule rules IPACL_MAX_RULES_PER_SET WORD protocol WORD port bool defaultPass F Code listing 20 6 IP ACL rule set IP rules can be configured using the web UI and in case the owner locks himself out by using the UART command interface Note that the ACL module is implemented on the TCP layer which means that it will not differentiate access to the public interface and access to the configuration interface If the ACL should only apply to certain web pages the module needs to rewritten and moved up to the application layer This is no great task and is a welcome feature for later development Configuration Since the HTTP server is such a major component of the TCP IP stack used in the OOD most of the stack configuration settings in TCPIPConfig h are directly tied to the web server The configuration file in its entirety is found in appendix A Many of the lines are self explanatory and aided with comments but a few sections deserve an explanation which is given in the following section 154 CHAPTER 20 TCP IP STACK Socket allocation and buffer sizes The total number of TCP sockets available to the HTTP server and the rest of the components in the stack must be determined at compil
143. ied version of the PIC24 s tick module is built on top of the existing tick module 22 3 UART and debugging Figure 22 1 UART to RS 232 level converter adapter Both microcontrollers have an UART port dedicated for printing useful informa tion and a simple command interface The main intention is to aid developing and debugging but the UART may also be used to perform rescue operations like reverting configuration and resetting passwords However the placement of the pin headers and the lack of level converters make the UARTs user unfriendly A level converter with a DSUB connector is needed to use the UART functionality with RS 232 An adaptor for this purpose is shown in figure 22 1 Alternatively an USB UART bridge can be used as illustrated in figure 22 2 on the following page Commands can be sent to the OOD using UART with a 115200 baud rate 8 bits with 1 stop bit and no handshaking or flow control Commands can have one or numerous arguments depending on the command Callbacks for commands are registered in an array using the function void uartbuf_init struct command commands size_t numCommands where command is defined in listing 22 4 on the next page A ring buffer is used to buffer UART input until a newline character is encountered The contents of the ring buffer up until the first space is then compared against all the registered 168 CHAPTER 22 OTHER MODULES AND SOFTWARE Figure 22 2 USB UART bridge struct
144. initions 40 41 42 43 44 45 46 47 48 49 50 51 52 53 55 16 3 GOL INTERFACING 115 ood pic24gfx X ft5x06 h enum ft5x06_gesture No gestured recognised FT5X06_GESTURE_none 0x00 Up gesture recognised FT5X06_GESTURE_up 0x10 Left gesture recognised FT5X06_GESTURE_left 0x14 Down gesture recognised FT5X06_GESTURE_down 0x18 Right gesture recognised FT5X06_GESTURE_right Oxic Zoom in expand gesture recognised FT5X06_GESTURE_zoomIn 0x48 Zoom out pinch gesture recognised FT5X06_GESTURE_zoomOut 0x49 Code listing 16 5 Gesture definitions frequency can be adjusted and it is 40 Hz at default Whenever a valid touch is registered the controller sends an interrupt signal to the PIC24 microcontroller This interrupt is used in the GOL interface layer to query for touch data only when necessary that is when there is new data available Along with an initialisation routine and methods for enabling and disabling the module only has one function bool touch_getTouchData GOL_MSG msg which fills the provided GOL message with coordinates and touch event toch_getTouchData is implemented using a simple state machine that sends a query if an interrupt has occurred waits for an 12C response if a query is already sent or fills the GOL message when a response is received The GOL message is only updated and valid if the function returns true The funct
145. internetphones 2013 Ac cessed Jun 13th 2013 Microchip Libraries for Applications http microchip com mal 2013 Accessed May 15th 2013 Mozilla Developer Network HTML lt input gt element https developer mozilla org en US docs Web HTML Element input 2013 Accessed Jul Ist 2013 Qt Project http qt project org 2013 Accessed Jun 19th 2013 Stack Overflow document on pageinit vs document ready http stackoverflow com a 14469041 2013 Accessed May 29th 2013 REFERENCES 211 60 61 62 63 64 65 66 67 68 Stack Overflow How jQuery Mobile handles page changes http stackoverflow com a 15806954 2013 Accessed May 29th 2013 The MIT License MIT http mit license org 2013 Accessed Jun 29th 2013 Wikipedia Near field communication http en wikipedia org wiki Near_field_communication 2013 Accessed Jun 28th 2013 Pradeep Budgutta AN1358 Developing Embedded Graphics Applications using PIC microcontrollers with integrated graphics controller C S Mitter AN1542 Active Inrush Current Limiting Using MOSFETs 1995 John Catsoulis Embedded Hardware O REILLY 2005 Andreas Misje Preliminary design of an out of office information system 2012 Newhaven Display International Inc NHD 4 3 480272EF ATXL CTP datasheet http www newhavendisplay com redirect html goto www newhavendisplay com 2Fspecs 2FNHD 4 3 480272EF ATXL CTP pdf a
146. ion assumes that the touch driver is the only software module accessing 12C which is perfectly fine since there are no other devices on the I C bus and no other software needs access to the touch controller 35 36 Parallel flash driver The parallel flash differs from the SRAM in that it is not under the sole and direct control of the graphics controller It also has a command interface and requires commands executed in order to write to memory The flash used M29W320DT follows the Open NAND Flash Interface Working Group ONFT specification and can be used with any flash software driver developed for an ONFI compatible chip A flash driver developed for the flash on the PIC24FJ256DA210 development board a SST39VF400A is re used for the flash on the OOD hardware with minor adjustments Both versions are included in appendix A 17 1 Accessing external memory using EDS The flash is accessed using EPMP The flash size and access time parameters are set in HardwareProfile h just like for the SRAM and the EPMP module is configured for both devices when the graphics driver is initialised Reading from an EPMP device is very simple using C By using the eds attribute the compiler ensures that addressing increments and decrements are done correctly event across page boundaries 29 p 8 Listing 17 1 shows how the flash start address is defined globally within the file with the correct modifiers The global definition is requried
147. ioned in the lower portion of the top layer so that the display does not have to stay on top of a tall component The choice of putting the cable through the PCB is because the PIC24 will be positioned on the bottom layer 58 CHAPTER 7 GRAPHICS AND DISPLAY Buffer 1 Buffer 2 a Stage 1 buffer 1 is draw buffer buffer 2 display buffer both buffers contain the same Buffer 1 Buffer 2 b Stage 2 buffer 1 is updated buffer 2 remains untouched Buffer 1 Buffer 2 O o Greetings MW c Stage 3 buffer 1 is now frame buffer buffer 2 draw buffer contents of both buffers unchanged Buffer 1 Buffer 2 O lt gt Greetings A Greetings d Stage 4 contents of buffer 1 is copied into buffer 2 Figure 7 7 How double buffering works 7 5 PCB DESIGN CONSIDERATIONS BULKY COMPONENTS DISPLAY Ea C CABLE BOTTOM SIDE Figure 7 8 Display s position and cable attachment 59 Power over Ethernet PoE is used to supply power along with data in a twisted pair TP cable Since the OOD is a wall mounted device as few cables as possible is desired By using PoE only a standard Cat 5 TP cable is needed to supply both power and data 28 p 62 The downsides are the need of power sourcing equipment PSE and need of possibly large components to convert the 47 V down to 3 3 V Extensive background theory on PoE is given in 66 so there will be no introduction on how PoE works The PoE PD and DC DC c
148. itial development with the PIC32 to provide Ethernet functionality It is connected to the PIC32 board using standard female female jumper cables 3 5 microSD board This small board houses a microSD card slot and a few decoupling capacitors It is connected to the PIC32 board using standard female female jumper cables 3 5 MICROSD BOARD Figure 3 5 microSD development board 27 Microcontrollers The microcontrollers are the most vital components in the OOD They are connected to all the other components and are needed to display information on the display and make Ethernet work As mentioned in chapter 1 1 Microchip is chosen as the manufacturer and the two microcontroller candidates proposed in 66 will used NFC reader 22 RGB al ba 3 I C touch LEDs Buzzer 2 UART 2 UART 3 4 SPI 2 UART 4 SPI 41 EPMP Ethernet transceiver SD card Figure 4 1 All the components in the OOD and how they are connected Due to the many dependencies between components there is no simple way of selecting components one by one A series of components that will interact together has to be reviewed at a time in order to make sure that there are enough peripherals of the right kind available on the microcontrollers Figure 4 1 shows the complete system with all the major hardware components and how they communicate with one another With this overview in mind it will be easier to
149. itle and a description as well as visibility settings which allows the title description to be hidden in the public web interface and or on the display Appointments are stored in arrays which are specific to days see listing 19 2 on the facing page If an appointment spans a day boundary it will be stored in all the days it affects This is not a space efficient solution and it complicates editing appointments which requires all the appointments to be edited However most appointments are expected to be short and there is plenty of space on the memory card to support this simple implementation See appendix A for the full source code 19 2 File structure The availability types and appointments calendar entries are serialised directly to file and these files not intended to be human readable The calendar uses two directories in the root directory availabilities and cal availabilities contains serialised availability type objects named by their ID zero prefixed to a fixed width of five For example the availability type unknown which is always present and created by the system if not is called 00000 User defined types are called 00001 and so forth IDs are reused when deleted so all appointments using a deleted availability type must be deleted as well The cal directory contains only subdirectories with a two digit integer name indicating year Every year directory contains subdirectories representing months with two
150. iv tag will be loaded As described best in 60 59 the possible remedies are either to include scripts within the page role div or include all scripts in the main HTML page which will be loaded and available for the remaining AJAX loaded pages The problem with the first solution is that scripts are reloaded unnecessarily they are loaded for every new page but could be loaded once for the whole application The problem with the latter is that if the user visits a page other than the main page enters the address manually or refreshes the page the page will not work because scripts will not be loaded The chosen solution is a version of the latter suggestion include all scripts for all pages in the header of all pages This can potentially dramatically increase the load time on first visit but it shortens loads for the remaining page loads After testing all solutions this is deemed the best Since the script import part of the header is exactly the same for all web pages it is included as a separate file using the inc functionality of the web server s dynamic variables see chapter 20 5 Listing 23 1 on the facing page shows the start of a typical HTML page in the web UI A header containing a title and a back button is added to every page and the remaining contents live in the div with the attribute role with the value content Query Mobile supports a way of theming pages by referring to themes with an attribu
151. ive drawing functions Graphical accelerators Display driver layer Display driver Display Figure 18 1 Microchip graphics library architecture Microchip s graphics library is a collection of software that provides everything from display controller drivers to a GUI object layer It was chosen for its na tive support for the PIC24 s integrated graphics controller and it also seemed to provide most of the functionality needed to implement a GUI for the OOD Figure 18 1 shows how the graphics library consists of four layers The arrows indicate how the layers and modules communicate Most layers only interact with its child layer with the exception of the application layer the user code The user may use the functionality in all layers interact with GOL objects perform drawing operations or manipulate the graphics driver directly The following in troduces the four layers bottom up 121 122 CHAPTER 18 GRAPHICS LIBRARY Display driver layer This layer consists of a device specific driver which implements the necessary functions for putting pixel data to the display If the device has any hardware acceleration this will be utilised to perform drawing more efficiently The integrated display controller in PIC24 comes with three graphical processing units GPUs one for drawing text using font tables one for copying rectangular areas and one for inflating compressed graphics These GPUs are used by the driver Primiti
152. kend specific the main limitation is the rate at which the web server can serve data The size of the HTML CSS and Javascript files need to be kept at a minimum And since the web server cannot serve requests truly in parallel the number of files required for each web page should be kept to a minimum The faster the web pages can be delivered and rendered to the user the more responsive the interface becomes The rendering lIn order to ensure correct behaviour when handling POST requests from numerous clients at a time the fetched data must be stored separately and not shared among all clients This is a matter of course but the original TCP IP stack implementation was flawed in several areas which had to be corrected 172 CHAPTER 23 WEB INTERFACE speed of a web page is very important as proved by measurements done by Google 53 Table 23 1 shows how a user reacts to delays in a web page Any delay over 100 ms feels sluggish to the user whereas delays over one second risks losing the attention of the user completely There are many techniques that can be used to make web sites faster many presented in 53 However optimising the web UI falls outside the scope of this thesis The main concern is to make an interface that works with the limitations of the web server and is usable from both mobile devices and desktop computers Optimising will have to be done at a later time Table 23 1 User reactions to various web page delays 53
153. ld provide 3D view of the PCB and components Although a two layer design was perfectly possible any further work and PCB redesign should reconsider using numerous layers 27 3 TCPIP and web server performance Microchip s web server was heavily modified to support FatFS and it was fixed to properly support numerous clients The results revealed a throughput of 550 kB s which is more than enough for the purpose of displaying the designed web UI However it is not enough for a larger number of simultaneous clients and should be increased if the OOD should handle heavier traffic This is necessary if a public web interface shall be provided Since the web throughput most likely is limited by the file system any further work should look into the possibility of using DMA to transfer bulks of data directly from SPI to the Ethernet transceiver RMID or perform optimisations in the library code 27 4 Further work Before continuing on developing hardware and software for the OOD time should be spent on considering whether it would be better to use hardware supporting a flavour of an embedded Linux OS This thesis has used microcontroller in order to test their limits and also because it would make it more achievable to design a PCB with little time and experience New commercially available hardware supporting PoE may become available and perhaps alternatives to PoE can be found Making a custom multi layer PCB is certainly also an option If t
154. le relative path support 2 also 2 enable f getcwd _ VOLUMES Number of logical drives to support 1 MAX SS Maximum sector size to support 512 MULTI PARTITION Multi partition support 0 USE ERASE Enable sector erase support 0 _ WORD ACCESS Enable word access support 0 _FS REENTRANT Enable reentrancy 0 _FS_ TIMEOUT Timeout period in time ticks 1000 _SYNC_t Syncronisation object type for reen HANDLE trancy support _FS_ SHARE Number of files that can be opened 15 simultaneously I O layer implementation and configuration Table 15 2 on the following page lists functions that need to be implemented by the user depending on the functionality wanted The disk_ functions are implemented in the PIC32 ported I O layer implementation mentioned earlier 93 100 CHAPTER 15 FILE SYSTEM Table 15 2 Required user implemented functions in FatFS 4 Function Required when disk initialize disk status Alwavs disk read disk write get fattime _FS READONLY disk ioctl CTRL_SYNC disk ioctl GET SECTOR COUNT disk_ioctl GET_BLOCK_SIZE TEMES disk ioctl GET_SECTOR_SIZE MAX SS gt 512 disk ioctl CTRL ERASE SECTOR USE ERASE USE LFN gt 1 ff convert ff wtoupper ff cre svncobj ff del svncobj ff req grant ff rel grant ff mem alloc ff mem free USE MKFS 1 USE LFN but the functions remaining are ff convert ff wtoupper ff_mem_alloc and ff_mem_fr
155. library lacks is a simple and less cumbersome way to implement menus pages It is up to the application code to destroy all widgets and create new widgets when the virtual screen changes This is not necessarily only a downside it gives the developer full control over how menus should be implemented The way this is going to be handled in the OOD is by wrapping the GOL layer in a state machine Each state will be a menu page and state changes will be triggered by events which could for example be touch input from buttons or timer timeouts State entry actions will do all object creating and drawing and exit actions will destroy objects and do necessary housekeeping Before discussing this implementation the configuration of the driver and the remaining graphics library will be explained followed by an introduction to the GOL 18 1 Configuration MAL depends on one file to hold all hardware configuration This file HardwareProfile h also holds the hardware configuration relevant for the graphics library The hardware the graphics library directly depend on is the SRAM and the display ood pic24gfx X HardwareProfile h define GFX_USE_DISPLAY_CONTROLLER_MCHP_DA210 define USE_16BIT_PMP define GFX_GCLK_DIVIDER 80 define GFX_EPMP_CS1_BASE_ADDRESS 0x20000u1 define GFX_DISPLAY_BUFFER_START_ADDRESS 0220000u1 480 2 272 16 8 2 522 240 027f800 double buffering define GFX_DISPLAY_BUFFER_LENGTH 0x7f800u1l 1 MB 1
156. lications will call callbacks for applications like the HTTP server and SNTP client Microchip s TCP IP stack is built for an cooperative multitasking time sharing system 47 p 144 This means that the stack along with other routines that need to do periodic work only has a limited time slot to perform its work before yielding the CPU to the next task This scheme will only work if the tasks have hard time limits and promise to exit when they should The TCP IP stack does not provide any details on the maximum execution time of its regular routines which is understandable as it depends heavily on how many and what components of the stack that are included This does not pose a problem for the system as no other components are very time critical The TCP TP stack is the most critical process and as long as its StackTsk is run often enough to process incoming traffic avoiding dropping packets there should be no problems Apart from these two functions the only other periodic stack related work that is performed is updating the DHCP_OK LED when the DHCP state has changed Ifa DHCP lease is obtained the new IP address is also printed on UART 20 4 Modifications Several modifications has been made to the TCP IP stack in order to make it work with the other software modules The first and biggest modification is the adaptation of the HTTP server so that it works with the FatFS file system The stack s HTTP server normally uses Microc
157. lity of a TCP IP stack with cryptographic support running on a system with limited resources Can the microcontroller run a stable web server with SSL TLS with acceptable performance e Since the hardware is to be custom made it would be more manageable for a person with very limited experience in PCB design to make a PCB 1Cross platform framework in C for creating graphical user interfaces GUIs 58 6 CHAPTER 1 INTRODUCTION with few layers and less complexity If the design can be restricted to two layers it can also potentially be prototyped using the department s milling machine and PCB production would be less expensive 1 2 Scope The work presented in this thesis includes a final design of the OOD a new look at the specification and requirements schematics and PCB design introduction to Microchip development tools and libraries and development of user interfaces Uls for both web and the display With such an array of different topics some of the topics will be given more focus than others Given that one of the objectives is to explore TCP IP and SSL on an resource limited system the topics related to TCP IP are given extra attention Details are also provided on how to set up a system similar to the development environment used in this project so that the results can be reproduced and improved The main focus in general is on software so more weight is put on describing software rather than the hardware There i
158. llback that it is associated with The other two fields record length and flags are not used in the source code and their purpose is unknown FileRerd bin and DynRcrd bin are located on the file system and must be updated when HTML files containing dynamic variables change since the variables offset will differ It is entirely possible to eliminate the need for these files and the need to generate and update them but that has not been a priority The binary record files and a header file including a function that maps IDs to callbacks called HTTPPrint h can be generated using a program supplied with MAL MPFS2 jar Microchip MPFS Generator Its use is explained briefly in a later section Modifications The minimum amount of promised TX buffer space of 16 bytes is too sparse in some occasions Although this limit can be adjusted by editing the source of the TCP IP stack it would be better to leave it relatively low for the many other shorter callbacks reducing the time spent on waiting for the buffer to empty In some cases the single state variable provided by the original HTTP server code has proved to be insufficient to store all necessary state data between calls to dynamic variable callbacks To remedy this a connection specific void pointer called dynVarWorkBuffer is made available for all callbacks This pointer is freed when non NULL whenever the client disconnects and a callback function is also free to free it if neces
159. llers The Norwegian University of Science and Technology NTNU has a lot of development equipment and easy access to products from Atmel Although there is nothing wrong with Atmel s solutions it would be beneficial for the Department of Engineering Cybernetics ITK to explore the solutions from other major manufacturers Microchip was chosen because it has a series of interesting 32 and 16 bit microcontrollers and cross platform development equipment Hopefully the results presented in this thesis will act as useful knowledge for some of the microcontrollers development tools and software libraries from Microchip Choosing a specific manufacturer is one of the architectural decisions The other major decision is the choice of using microcontrollers instead of solutions that can run operating systems like an embedded version of Linux Using an open source full blown operating system would possibly eliminate a lot of low level code used to interface hardware and could shift the focus towards writing the main application aimed to solve the out of office problem There would be no need to fiddle with a TCP IP stack Linux comes with a well tested and robust implementation and frameworks like Qt would make it a lot less cumbersome to write a GUI to the display A microcontroller solution was chosen in favour for an ARM processor with embedded Linux for two main reasons e It would act as useful research to find the limitations and usabi
160. ly connected 6 The PCB placement and routing constrains for the LAN8720 see chapter 5 4 need to be followed 7 The complexity of routing the many EPMP and RGB signal lines must be kept in mind With all of these requirements in mind the placement and routing process followed a trial and error approach until a good solution was found Figure 10 1 shows the suggested positions of the components The 8P8C connector will be at the bottom with all the large components for PoE and power supply The upper pin headers will not normally be accessible when the PCB is enclosed in a plastic housing but can easily be accessed when dismantled which is okay for programming and debugging purposes The NFC UART and power pin header is positioned such that the cables can be routed out of the body in any direction PIC24 and its memory devices are put on the underside with the 70 CHAPTER 10 PCB DESIGN AND ASSEMBLY graphics connectors on top This was the end result after a lot of trial and error because the many signals were difficult to route on two layers 10 4 Finished design an BER2 C26 R30 C11 C36 C35 mu YS mu Wi Top layer MM Bottom layer Figure 10 2 The finished PCB design Figure 10 2 shows the finished PCB design The available area ended up being well utilised and the upper right corner in particular is completely covered Figure 10 3 on the next page shows a close up of the PIC24 SRAM and parallel flash with the EPM
161. ly needed they can be recognised by making a module that parses the touch coordinates 16 3 GOL interfacing As opposed to using a resistive touch screen where it is necessary to constantly scan for touches the capacitive touch controller does this automatically The scan 114 CHAPTER 16 TOUCH CONTROLLER DRIVER ood pic24gfx X ft5x06 h 104 struct touchInfo 105 106 Gesture if any recognised see ft5z06_gesture 107 unsigned char gesture 108 Number of touch points registered 109 unsigned char numPoints 110 Ak TIA brief Array of registered touch points x If numPoints is not 5 the remaining touchCoor objects in the 113 array have 114 undefined values 115 116 struct touchCoor points 5 1 117 das Code listing 16 3 touchInfo object ood pic24gfx X ft5x06 h 60 enum ft5x06_touchEvent 61 EE 62 The finger was put down on the touch surface 63 FT5X06_EVENT_putDown 0 64 JK 65 brief The finger was lifted from the touch surface 66 The touch coordinates are not valid for touch data with this 67 event Touch points with this event is not included in the number of 68 points 69 counter 70 74 FT5X06_EVENT_putUp 1 7a The finger is still in contact with the touch surface 73 FT5X06_EVENT_contact 2 This event is reserved and should be treated as an invalid event 74 2 4 75 FT5X06_EVENT_invalid 3 76 Ba Code listing 16 4 Touch event def
162. ly the necessary number of points may be queried Querying the touch controller is implemented as an 12C read request to the touch controller s address 0x38 to register address 0x01 The length of the data that is expected depends on the number of points Table 16 1 on page 113 shows how the data is laid out in the register map If only information about gestures and the first touch point is needed six bytes are needed Listing 16 2 to 16 3 on pages 113 114 shows the touchCoor and touchInfo objects These are populated by ft5106_retrieveTouchInfo The valid events 112 CHAPTER 16 TOUCH CONTROLLER DRIVER ss RIA e TO APA int i2c_puts unsigned char address unsigned char reg unsigned char 192 data 193 size_t len 194 195 if i2c_error 196 return I2C_ERR_inErrorState 197 198 if i2c_state I2C_STATE_disabled 199 return i2c_error I2C_ERR_disabled 200 201 if i2c state I2C STATE idle 202 return i2c error 12C_ERR_busy 203 204 i2c state I2C STATE error 205 206 if I2C TRX BUFFER SIZE lt 2 len 207 return i2c error I2C_ERR_TXBufferOverflow 208 209 if len 210 len strlen char data 211 212 TRXBufferLen 2 len 213 TRXBufferCurrPos 0 214 215 TRXBuffer 0 address lt lt 1 amp Oxfe 216 TRXButfer 1 reg 217 218 sizot i 219 for i 0 i lt len i 220 TRXBuffer i 2 datal i 1 221 222 numRXBytes 0 223 224 se
163. m was studied and a design of a system that aimed to solve the problem was presented The system was named out of office display OOD and had the following suggested features A colour TFT LCD touch display dimensioned to contain availability informa tion as well as the office occupant s name and portrait The touch interface allows passer bys to interact with the system and access additional menus and features An Ethernet network connection that connects the OOD to the office network or Internet allowing the owner to update information remotely The device also optionally hosts a public web site where the current availability status can be read This eliminates the need to go to the office door to check for the updated information on absence 1 1 BACKGROUND 5 Power provided by power over Ethernet PoE which eliminates the need for battery replacement and reduces cabling to one cable for both power and network The design 66 also included thorough theory on PoE which was used to design power supply circuitry The remaining main hardware components were selected based on the specifications and main software libraries were suggested Choice of architecture In the design 66 a somewhat unconventional method was used to select the system architecture and type and family of microcontrollers The manufacturer was chosen first The reason behind this was an objective of gaining knowledge of a lesser known family of microcontro
164. me ending in md5 Appendix A lists two files random and random md5 which were used to produce the following results Results The size of the file used in the test random is exactly 10 MB Three runs resulted in a very similar test duration 16538 16566 and 16577 ms the data read was verified successfully in all three tests The average read performance is 618 kB s which is acceptable but not impressive The current implementation can be improved by utilising the microcontroller s DMA capabilities Blocks of data can be transferred to and from the SD without any intervention from the CPU With its unrestricted license ease of use and readily available I O layer port FatFS has proved to be a great choice of file system implementation The read results are good enough for the OOD application and they can most likely be improved by utilising DMA in a future upgrade 106 CHAPTER 15 FILE SYSTEM fatFSTest main c 140 static void readTest const char fileName 141 142 HASH SUM md5 143 MD5Initialize md5 144 145 FIL f 146 FRESULT retVal f open kf fileName FA READ 147 148 unsigned int duration 0 149 unsigned int numBytesReadTotal 0 150 unsigned int prevTimestamp ReadCoreTimer 151 while f_eof amp f 152 153 unsigned char buffer 512 154 unsigned int numBytesRead if retVal f read amp f buffer sizeof buffer amp numBytesRead 155
165. me is a scarce resource and will affect the whole project long lead times are undesirable and there is most likely only time for making one complete prototype Software libraries that are easy to use and eliminate need for self written libraries will be preferred This is an educational project but some care is taken with regard to making a commercial product Any choices that would greatly affect the feasibility of continue developing finishing and mass producing the OOD as a commercial product are avoided when possible Physical dimensions The OOD should be as small as possible The depth should be prioritised so that the device do not protrude too far out of the wall it will be mounted on In order to achieve this some of the bulky components can be placed so that they are no longer directly behind the display An small increase of the width or height of the device is more preferable than having a thick device Network The choice of network technology in the preliminary design was done along with the choice of display and power supply Instead of choosing to use battery as a power source along with an energy efficient display and a wireless network technology colour LCD was chosen for display Ethernet as network technology and PoE for transporting power Ethernet is a complex network technology that can be challenging to implement in embedded systems but it also fulfills the most important needs for network in the OOD 2 3 SPEC
166. microcontrollers is PICkit 3 The tool is connected to the computer using USB and programs microcontrollers using ICSP The ICSP pin out at the PICkit 3 programmer is shown in figure 14 1 on the next page The sixth pin of the ICSP standard connector is not used so it is not included on the OOD programming pin headers Note that the microcontroller do not receive power from the PICkit 3 programmer and needs its own power source during programming I The GNU Compiler Collection http gcc gnu org 91 92 CHAPTER 14 DEVELOPMENT ENVIRONMENT Aux not used ICSPCLK ICSPDAT VPP MCLR Figure 14 1 ICSP pin out seen at PICkit 3 programmer Microchip software libraries The Microchip application libraries MAL is used for its graphics library and TCP IP stack The library is downloaded from Microchip s website and unpacked into a directory after agreeing to the software license if you do agree The file structure is shown in table 14 2 on the facing page The path to the Include directory must be added to a MPLABX project s search path in order for the compiler to find the library code Most of the library components depend on the file HardwareProfile h to be present in the programming project often along with a library specific configuration file HardwareProfile h contains definitions telling MAL what hardware is used and how it is configured The contents on the HardwareProfile h files one for each microcontroller used in th
167. mp action url 2012 Accessed Dec 10th 2012 Andrew S Tanenbaum and David J Wetherall Computer Networks Pearson Education inc fifth edition 2011 Part V Appendix Source code The source code is provided on a medium attached to the last page of the print on DAIM and on http ood 2tsa net where the project will be continued after the thesis Table A 1 lists the contents of the source code Table A 1 Source code contents File name Description fatFSTest FatFS read test MPLABX project random FatFS read test test file random md5 md5 hash of random file HTTP2 fatFS c patch Patch for the HTTP server LICENSE License file mal v2013 02 15 patch Patch for MAL ood mcuC Inter microcontroller communication library pic24gfx X PIC24 code MPLABX project pic32eth X PIC32 code MPLABX project A 1 MAL patch The patch for the Microchip application libraries MAL is located in mal_v2018 02 15 patch Follow these steps to apply the patch 1 Download MAL version v20113 02 152 and install it 2 Enter the directory the library was intalled in and enter the directory Microchip 3 Apply the patch using the tool patch use the full path to the patch file Digital Arkivering og Innlevering av Masteroppgaver DAIM http daim idi ntnu no 2http microchip com mal 215 216 APPENDIX A SOURCE CODE patch p1 lt mal_v2013 02 15 patch A 2 HTTP server patch The patch for the FatFS adopted HTTP ser
168. mponents were placed on the wrong side of the PCB This was a major design error that should have been noticed much earlier The implications of this design error is that instead of keeping the OOD s dimensions slim the overall thickness is now extra thick The bulky components are on the top and the display on the back This is nonetheless no catastrophe as long as no functionality is effected which later tests will confirm The assembly started out with the LAN8720 QFN which was soldered by pre tinning the pads adding flux and using hot air It worked flawlessly The remaining assembly was performed in no particular important order other than soldering components in a way such that access to other components with the soldering iron would not be obstructed Figure 10 7 on page 75 shows the the completed OOD cables are used in lack of the right pin headers in the upper left corner 10 7 Testing and verification Various smaller tests were performed during assembly The power supply circuit was soldered and tested by using a PSE before continuing The PIC32 was soldered programmed and tested before soldering the PIC24 The PIC24 was ensured to be working before adding display connector and memory ICs A few 74 CHAPTER 10 PCB DESIGN AND ASSEMBLY JP4 JP3 JP2 JM S31 TE Y70129 29143162 ao oe AS a D EA THD 10909 199 Hoss an En 1 aa 2327 ant R18 C13 C14 tea ver 1 8 C26 R38c11 Ba zu A C36 35 KA B c12 OOD Andreas Misj
169. n chosen file system implementation frees over 200 lines of string manipulation code part of which is necessary due to lack of LFN support which is enabled in FatFS Numerous chdir calls removed A number of sections of code where the current directory was changed to the www root directory is removed They are not necessary since the www root directory is never left when using FatFS File handle pool added The file open functions for both MPFS and MDD return a file handle whereas FatFS f_open takes the file handle as an argument and returns a status integer In order to keep compatibility with the other file systems a pool of file handles is allocated on the stack in FileSystemInit When a file is opened a free file handle is picked and when the file is closed the file handle is freed This behaviour is not strictly needed for the OOD application and can be removed but a positive side effect is that it makes it easier to restrict the number of files the HTTP server may open Whilst adapting the HTTP server code a few flaws were discovered and corrected The server is meant to support simultaneous connections but it still relies on global variables and static variables in functions There is no guarantee that these variable remain the same between iterations of handling queued requests This issue manifested itself when loading the web UI using a normal modern desktop web browser which utilises multiple connections in p
170. nctions perform on an ordinary 32 bits microcontroller with no cryptographic hardware acceleration SSL is easy to set up in the stack Apart from the settings directly related to the number of sockets sessions that should be supported the only two other set tings are SSL_RSA_KEY_SIZE and HTTP_NO_AUTH_WITHOUT_SSL The latter define is important preventing the owner from circumventing using HTTPS on web sites requiring authentication The former tells the SSL module the length of the RSA key used which will be discussed in the next section When SSL is enabled the HTTP server listens to port 443 in addition to port 20 6 SSL 157 80 and all the necessary work is performed automatically in the stack Generating and using SSL certificates Two certificates are included in the appendix one 1024 bit long and one 2048 bit long They are both generated using the following steps details are found in 47 p 469 471 The OpenSSL toolkit is needed along with Perl in order to run the parse pl script oodCert will be used as the name for all the resulting files and the example will use 2048 bits 1 Generate a key openssl genrsa out oodCert key 2048 Generate a certificate signing request CSR An interactive prompt will ask for details that need to be entered openssl req new key oodCert key out oodCert csr Generate the X 509 certificate by either self signing or using a certificate authority Self signing valid for ten year
171. nd modification of the provided source code as long as it is intended for Microchip products Since PIC24 and PIC32 are Microchip products this poses no problem but it is unclear what authorised modification of the code is Perhaps it is a way for Microchip to demand inspection of the 90 CHAPTER 13 ARCHITECTURE modified source code if they so wish Redistribution of the MAL source code and documentation requires the recipients to agree to the license agreement It is because of this reason that none of the MAL code is supplied with the thesis This also affects the modifications made to the MAL code The best solution found to this problem is to supply patches rather than the actual source code In order to get hold of all the source code for this thesis the MAL needs to be downloaded and the patches supplied in the appendix need to be applied to the MAL code This is cumbersome but necessary to comply with the agreement It is unclear whether these requirements affect the remaining code that is not directly used together with MAL The code supplied in this thesis will be publicly available and it should be so under the terms of a well known and understandable license like GPL 20 LGPL 21 MIT 61 BSD 15 or Apache 2 The license chosen is GNU General Public License GPL in order to ensure that any derivative work will also be open source Development environment Developing software for microcontrollers require special compiler
172. ndStartCondition 225 226 return I2C_ERR_noError 227 Code listing 16 1 IC driver routine for sending array of data for the FT5x06 touch controller is defined in listing 16 4 on page 114 and the gestures are defined in listing 16 5 on page 115 Note the comment about the put 87 88 89 go gl 92 93 95 16 3 GOL INTERFACING 113 Table 16 1 Excerpt of FT5x06 operating mode register map 30 p 4 5 Address Description 0x01 Gesture ID 7 0 0x02 Number of touch points 3 0 ii oe da al Ist touch X position upper byte 11 8 0x04 1st touch X position lower byte 7 0 0x05 1st touch ID 3 0 1st touch Y position upper byte 11 8 0x06 1st touch Y position lower byte 7 0 0x07 0x08 Pattern address 3 8 repeats for touch point 2 5 ood pic24gfx X ft5x06 h struct touchCoor X coordinate unsigned int x Y coordinate unsigned int y Touch event see ft5x06_touchEvent enum ft5x06_touchEvent event de Code listing 16 2 touchCoor object up event Since this event is registered when the finger is no longer on the touch screen the coordinates for this touch point are invalid and set to Oxffff It was discovered after extensive testing that only two of the five gestures are actually recognised by the touch controller This has been reported to Newhaven but no solution has been found to fix the problem These gestures are not critical and if real
173. ne another Once the components are picked the schematic circuit diagrams are drawn and at the same time developing drivers can begin With the help of development boards for the components chosen or similar components drivers can almost be completed before the customised hardware is produced When the circuit diagrams are completed and controlled the PCB is designed Components are purchased and PCBs manufactured soldered by hand and tested and verified electrically and by simple test programs With the aid of development boards the software can be developed while the PCB is designed and while waiting for production to complete When the hardware is assembled the software is tested on the hardware and developed further The web pages can also to a certain degree be developed without the hardware in hand but due to the use of an embedded web server challenges such as emulating the behaviour will be difficult In practice only the planning of menus and visual design will be done before the hardware and software is completed Both the hardware development PCB design and web design are fairly new areas for the author The double arrows in figure 2 5 indicate that the process is going to go backwards and forwards almost through all steps Due to the limited previous knowledge in web design the design process may undergo numerous iterations before the right libraries are found and the right techniques employed Working with complex libraries
174. ng page shows the necessary connections for the microSD card slot The pin out in table 6 1 is used to connect SPI lines and a decoupling capacitor is added to the voltage supply The card detect pins CD are connected to a pull up resistor and ground so that a present card will be indicated by a low signal and an absent card will be indicated with a high signal 6 2 Parallel flash The PIC24 microcontroller can retrieve data from the aforementioned SD card card through the PIC32 using the communication lines between them It is not expected that this will be a significantly fast method since the data must go through two communication lines and two CPUs The PIC24 needs efficient access to GUI items that need to be drawn on the screen especially large fonts 6 2 PARALLEL FLASH 47 Q Oo l Q N o So N kl x ir S je O H UDD GND Figure 6 2 microSD card slot circuit diagram and images like the portrait to be shown on the main screen Two solutions will be considered e The necessary data can be loaded from the SD card through the PIC32 during boot and stored in available room in the frame buffer SRAM for very efficient access e The necessary data can be kept in local efficient non volatile storage The first solution could work well but it would demand a lot of storage which would require an expensive SRAM In will nontheless be tested so the capacity of the chosen SRAM will be selected so th
175. nnections The remaining numbers varied a bit from each test run which show that the server is not completely fair Some clients may be served in a significantly shorted time than others The numbers do not bring any negative and positive surprises A client using multiple connections will not receive files any faster neither noticeably slower The last two tests used a large file in order to get stable throughput measurements Files of this size are not representable for the normal content served by the web UI Most files are a few kB large and some JavaScript libraries in the order of a few 10 kB Tests were performed on small files as well in order to make sure that the behaviour was still the same The results from a test using 10 users repeating 10 requests for a file 10 4 kB large is listed in table 26 2 on the facing page The majority of the responses took either a few milliseconds or a few tens of milliseconds but a very few took a few seconds The reduced throughput is probably the result of TCP slow start and the small file size there is not enough time to achieve the maximum rate before the transfer is finished 26 1 WEB SERVER AND WEB UI 197 The results show expected behaviour apart from the occasional extraordinarily long delay It would seem that the client is queued and not served until a number of other clients are finished The reason for this is not known Table 26 2 10 concurrent users 10 repetitions using a 10 kB file
176. not limited to the subnet s used on the premises the owner may want to disable the public interface or limit the information published The configuration and administration pages will require authentication so that only the owner can access them NFC reader A contactless card reader provides a very quick and effortless means of authentication to the display UI It can be used by the owner to quickly log in to a set of administration menus on the OOD and most importantly give the owner a way to quickly change his availability status as he arrives or leaves his office By flicking his ID card or NFC capable mobile phone the owner can quickly choose a new status from a special menu 14 CHAPTER 2 SPECIFICATION AND SYSTEM DESIGN 2 3 Specification In order to choose the right hardware components and the suitable software libraries a detailed specification needs to be made The specification in the preliminary design 66 is used as a basis with necessary changes based on results presented in the paper In addition to the specific requirements for the various components of the system there are a few general guidelines that applies to the whole project Cost All hardware components are chosen with price in mind both for single units for the actual cost for prototyping and volume prices with mass production in mind Price and availability of components may nonetheless end in choosing non optimal components for prototyping Time Ti
177. nsidered significantly private so there is no need to encrypt all traffic There must be a way to disable the public interface Preferably there should be an option for the owner to restrict access based on IP addresses so that access can be limited to the company subnet s 2 4 Final design Figure 2 4a to 2 4b on the following page suggest how the OOD would look housed in a plastic casing 66 The extension in the bottom is in order to make room for some of the larger components mainly the 8P8C connector and capacitors and coils for the power supply As figure 2 4b shows the height of the 8P8C connector makes it the tallest component in the OOD and defines the overall depth of the device Placing it behind the display rather than below it would increase the depth further Making the casing will not be a part of the scope of this thesis 18 CHAPTER 2 SPECIFICATION AND SYSTEM DESIGN 101 50mm 63 20mm a Top view 31 59mm 51 50mm 47 57mm b Bottom view Figure 2 4 OOD in plastic housing with expected dimensions 2 4 FINAL DESIGN 19 but suggested shape of the end product pays an important role in designing the PCB Design process The design and development are done in three parallel process as illustrated in figure 2 5 on the next page 1 Hardware 2 Embedded software 3 Web pages The hardware development starts with choosing components that fulfill the specification and that are compatible with o
178. nstance could be loading graphics or fonts from slow memory or doing computationally expensive transformations may be noticeable on the display For very slow operations this can be seen as line by line updates which gives a unpleasant user experience This issue can be solved by using two buffers one frame buffer whose content is visible on the display and a second buffer named the drawing buffer see figure 7 7a on page 58 All updates are now performed in the draw buffer and can take as long as needed since the changes are not shown on the display figure 7 7b When the drawing is completed the display controller swaps the memory addresses in an instant and uses the previously known draw buffer as its frame buffer figure 7 7c The new draw buffer now 7 5 PCB DESIGN CONSIDERATIONS 57 contains the previous frame Before drawing can continue the content in the new display buffer the content recently drawn is copied into the new buffer figure 7 7d The buffers are now identical and the process continues 63 p 30 Double buffering is handled by the graphics library driver and is fully utilised by the GUI layer used see chapter 18 2 7 5 PCB design considerations As mentioned in the specification an overall design goal is to get the OOD as thin as possible Figure 7 8 on page 59 illustrates where the display is intended to be in the product and where the flat cable is mounted The bulky components are all attempted posit
179. nt errors in the web server the web server software has been modified and given a HTTPReset function This function is called at line 316 resetting all file handles used in the web server preventing undefined behaviour and fatal errors ood pic32eth X fatFS mmcPIC32 c void disk notifvCDChange WORD cardPresent f if cardPresent Stat amp STA NODISK else Stat l STA NODISK STA NOINIT int disk_cardPresent return Stat amp STA_NODISK l Code listing 15 4 Functions for setting and retrieving card present state 104 CHAPTER 15 FILE SYSTEM ood pic32eth X main c 260 static void checkIfMemCardPresent 261 262 static bool stateEverProbed false 263 static bool prevState true 264 static bool waitingForDebounce false 265 static DWORD prevTick 0 266 267 if stateEverProbed 268 a 269 stateEverProbed true 270 prevState PORTEbits REQ 271 return 272 273 Wait for switch debouncing for 100 ms before determining final 274 state 275 if waitingForDebounce 276 277 if TickGet prevTick gt TICKS_PER_SECOND 10 278 279 waitingForDebounce false 280 281 if PORTEbits RE9 prevState 282 return 283 284 prevState PORTEbits RE9 285 disk_notifyCDChange prevState 286 HTTPReset 287 288 289 290 else if PORTEbits RE9 prevState 291 292 prevTick TickGet 293 waitingForDebounce true 294 295
180. ntinued 15 3 File system structure All software modules that need to keep data between power cuts use the SD card and the FAT32 file system Files are stored in directories according to their function or the software module that uses them Table 15 3 on the next page shows the typical contents of the root directory Details of the various files and sub directories are found in the chapters dicussing the respective modules 108 CHAPTER 15 FILE SYSTEM Table 15 3 The file system structure seen from the root directory Directory file name Function availabilities cal passwd file settings WWW Stores the availability types used by the calendar module see ch 19 Stores appointments and other data for the calendar module File containing usernames and password salts and hashes used for authenticating owner in the web UI see ch 20 5 Contains configuration files for all mod ules that will be read on boot The root directory for the web server Everything in this folder is accessible over HTTP but some directories and files may require authentication see ch 20 5 Touch controller driver GOL interface FTx06 driver 12C driver Figure 16 1 Architecture of the touch driver The touch controller integrated in the Newhaven display was briefly discussed in chapter 7 1 It is capable of tracking five points simultaneously it recognises five different gestures and supports 12C and SPI In o
181. ocol HTTP is a protocol in the application layer of the Open Systems Interconnection OSI model and depends on a series of underlying protocols 68 ch 7 3 Tn order to deliver a web page to a client over Ethernet all of these protocols need to be implemented in the microcontroller This software component will be referred to as the Internet protocol suite TCP IP stack Implementing a TCP IP stack from the ground up is a huge task It would also be completely unnecessary since there are many existing implementations for embedded systems The TCP IP stack implementation suggested in 66 is from Microchip and is a part of MAL The only change from the original requirements for a TCP IP stack implementation is the need for a NTP client The MAL s TCP IP stack has a SNTP implementation that can be used with a few minor adjustments The main reasons for choosing Microchip TCP IP stack rather than other free open source alternatives are e It is tailored for PIC microcontrollers and can be used out of the box without any modifications or need to write I O layers e It has a promising documented transmit throughput with the PIC32 s internal Ethernet controller 2543 kB s with an 8000 byte transmit buffer 14 e It includes support for SSL The first reason is important This project is time constrained so choosing a TCP IP stack that can be used without any major modifications such as providing a driver for the Ethernet controller
182. ocumentation 2012 LAN8720A LAN8720Ai Datasheet 2012 210 REFERENCES 47 Microchip TCP IP Stack Help Part of the Microchip Application Library 48 49 50 51 52 53 54 55 56 57 58 59 help documentation 2012 PIC24FJ256DA210 Family Silicon Errata and Data Sheet Clarification http waw microchip com TechDoc aspx type errata 2012 Accessed Feb 14th 2013 PIC32 GUI Development Board with Projected Capacitive PCAP Touch Information Sheet http www microchip com Microchip WWW SecureSoftwareList secsoftwaredownload aspx device en560014 lang en amp ReturnURL http www microchip com stellent idcplg IdcService SS_GET_PAGE amp nodeld 1406 amp dDocName en560014 2012 Accessed Mar 31st 2013 Routing Checklist for the LAN8720 24 pin QFN Package 2012 Schematic Checklist for the LAN8720 24 pin QFN Package 2012 UM10204 12C bus specification and user manual October 2012 Breaking the 1000 ms Time to Glass Mobile Bar rier https docs google com presentation d 1qbqqcf jz3YwocRZu2led3CzhjHjcTvvQVSYETOQYyL4 edit pli 1 slide id p19 2013 Accessed Apr 12th 2013 FatFs Generic FAT File System Module updates http elm chan org fsw ff updates txt 2013 Accessed Jun 5th 2013 Global mobile statistics 2013 Part B Mobile Web mobile broadband penetra tion 3G 4G subscribers and networks http mobithinking com mobile marketing tools latest mobile stats b
183. ogs in the entered password will be hashed along with the previously used random number called the salt and compared against the saved hash The process is illustrated in figure 20 4 The owner can update his password and user name in the web Ul and in case he should lose his password he can also perform updates using UART ACL It can be useful to filter visitors to the public web interface based on their source IP addresses This way the access to the public interface and or the configuration pages can be limited to only the university company network A simple module is made to allow this and is used in the transmission control protocol TCP layer before passing the connections to the HTTP server Listing 20 5 on the facing page shows the format of an IP ACL rule and listing 20 6 on the next page shows the format of a rule set The module is implemented so that it is not specific for HTTP but for any port although only port 80 will be used in the 00D An incoming TCP connection s destination port will be used to match a 27 28 29 30 32 39 40 41 42 44 20 5 HTTP SERVER 153 ood pic32eth X ipACL h struct ipACLRule IP ADDR srcAddrRangeStart IP ADDR srcAddrRangeEnd bool pass bool ruleEnabled F Code listing 20 5 IP ACL rule rule set and the source address will be compared against the IP ranges in the matched rule set If the address matches a range with its pass variable set to false it will be den
184. oller from both the 32 bit and 16 bit architecture families have been used and their peripheral features have been tested extensively The PIC24FJ256DA210 is advertised as a microcontroller built for graphics applications and it does not disappoint It is a low powered device capable of driving the chosen WQVGA dis play entirely without CPU intervention and provides an efficient memory copying GPU for double buffering It will also support VGA resolutions if a larger display should be needed The PIC32MX695F512L has also impressed with its Ethernet capabilities large amount of flash and RAM and computing power Microchip has recently started supplying all of their development tools and libraries with multi platform support Along with an Linux supported ECAD tool Eagle this made it possible to do all development on one single operating system of choice Debian Microchip application libraries used to provide the TCP IP stack HTTP server and graphics also provides other libraries including a USB stack and WLAN support and can be useful for other projects using Microhip It must be noted however that although the software is free it comes with a license that should be studied thoroughly 201 202 CHAPTER 27 DISCUSSION AND FURTHER WORK 27 2 OOD hardware The hardware has already been discussed in chapter 11 The resulting PCB was successful despite a few flaws A design error could most likely have been avoided if the ECAD tool cou
185. on shared bus each of the microcontrollers can be given their own storage units A smaller fast memory can be given the PIC24 and a larger memory accessed with a file system can be given to the PIC32 to store images and HTML files The shared resources calendar data settings owner s name and title and so forth can be forwarded by the PIC32 to the PIC24 in a format the PIC24 prefers This way the PIC24 will not have to implement support for a file system to access files The two types of memory devices used will be a microSD card and a parallel flash as suggested in 66 6 1 microSD card SD SPI 9 DAT2 91245678 1 CAT3 CS 2 CMD SI 4 VDD 5 CLK SCLK 6 Vss 7 DATO DO 8 DATI Figure 6 1 amp Table 6 1 microSD card pin out The reasons for choosing a microSD card are many They are very cheap come with great capacities they are very small and together with their larger version Secure Digital SD they dominate the memory card market and is the de facto standard Even the smallest capacity cards available at the moment normally 2 45 46 CHAPTER 6 NON VOLATILE MEMORY GB have far more storage than the OOD will ever need Being able to remove the memory is not an important feature in a production model but it is a very useful feature during development During web development it is necessary to test the web pages on the embedded web server which is a trivial task when the memory card can be removed and inserte
186. on used Purpose Purpose details Alt function Comments Moveable 95 PMA16 CN81 RG14 PMA16 Parallel bus Address bus 92 AN22 PMA17 CN40 RA7 PMA17 Parallel bus Address bus 40 RPI32 PMA18 PMA5 2 CN75 RF12 PMA18 Parallel bus Address bus PMAS 19 AN21 RPI34 PMA19 CN67 RE9 PMA19 Parallel bus Address bus 14 AN20 C2INC RP27 PMA2 CN11 RG9 PMA2 Parallel bus Address bus 59 SDA2 PMA20 PMA4 2 CN36 RA3 PMA20 Parallel bus Address bus PMA4 Alt Touch C 12 AN19 C2IND RP19 PMA3 PMA21 2 CN10 RG8 PMA3 Parallel bus Address bus 11 AN18 C1INC RP26 PMA4 PMA20 2 CN9 RG7 PMA4 Parallel bus Address bus PMA20 10 AN17 C1IND RP21 PMA5 PMA18 2 CN8 RG6 PMA5 Parallel bus Address bus PMA18 29 VREF PMA6 CN42 RA10 PMA6 Parallel bus Address bus 28 VREF PMA7 CN41 RA9 PMA7 Parallel bus Address bus 50 RP17 PMA8 CN18 RF5 PMA8 Parallel bus Address bus 49 RP10 PMA9 CN17 RF4 PMA9 Parallel bus Address bus 18 RPI33 PMCS1 CN66 RE8 PMCS1 Parallel bus Chip select SRAM 9 AN16 RPI41 PMCS2 PMA22 2 CN48 RC4 PMCS2 Parallel bus Chip select flash 93 PMDO CN58 REO PMDO Parallel bus Data bus 88 VCMPST2 SESSVLD PMD10 CN69 RF1 PMD10 Parallel bus Data bus 94 PMD1 CN59 RE1 PMD1 Parallel bus Data bus 87 VBUSST VCMPST1 VBUSVLD PMD11 CN68 RFO PMD11 Parallel bus Data bus 79 RPI42 PMD12 CN57 RD12 PMD12 Parallel bus Data bus 80 PMD13 CN19 RD13 PMD13 Parallel bus Data bus 83 C3INB PMD14 CN15 RD6 PMD14 Parallel bus Data bus 84 C3INA SESSEND PMD15 CN16 RD7 PMD15 Parallel bus Data bus 98 PMD2 CN60 RE2 PMD2 Parall
187. onnection The behaviour was somewhat consistent depending on the browser used Figure 26 2 shows the SYN and handshake packet 219 ms apart The tests were done with both 1024 bit and 2048 bit RSA keys but the results were very similar With this information in hand it is clear that there is no good reason to use any smaller key size than 2048 bits The average throughput using SSL using test jpg was a relatively impressive 317 kB s 64 of the normal throughput TCP IP stack stability More important than the performance is the stability of the TCP IP stack It should never be needed to reset or restart the OOD due to segmentation faults or forever looping code sections After completing the modifications and extensions to the HTTP server the server and TCP IP stack was run for a long period of time during web UI development It did not show any instability issues and never caused the system to crash However as pointed out earlier in the performance tests there have been a few cases of a few inconsistent and inexplicable delays 26 1 WEB SERVER AND WEB UI 199 gt Internet Protocol Version 4 Src 10 10 10 10 10 10 10 10 Dst 10 10 10 11 gt Transmission Control Protocol Src Port 43730 43730 Dst Port https 443 Y Secure Sockets Layer Y SSLv3 Record Layer Handshake Protocol Client Hello Content Type Handshake 22 Version SSL 3 0 0x0300 Length 117 Y Handshake Protocol Client Hello Handshake Type Client H
188. onverter circuit is based on the prototype made in 66 along with a few modifications 1 Smaller components have been used where possible A different coil and Schottky diode is used which reduces both the footprint and height of the circuit 2 A different connector is used as mentioned in chapter 5 which is significantly slimmer at the cost of being a bit wider 3 An inrush current limiting circuit is added to make the circuit work as intended 8 1 Inrush current limiter The inrush limiter is added after having discovered that surge currents from the capacitors used in the DC DC converter were exceeding the permitted limits in the PoE standard This made the PoE controller cut the power and the device would never turn on The inrush limiter is based on a MOSFET design from a Motorola application note 64 Figure 8 1 on the following page shows the inrush current limiter A capacitor C4 is used to control the gate charge of the MOSFET The circuit will slowly at the rate of tens of ms connect RTN ground from PoE to the circuit GND R14 1The voltage supplied by PoE can vary from 44 V IEEE 802 3af or 50 V IEEE 802 3at to 57 V measured at PSE IEEE 802 3af 61 62 CHAPTER 8 POWER OVER ETHERNET 2 z a i R8 C4 ol a2 ES fl 1 R10 DNP D3 rr DHNS R14 S TIN a aja GND A c5 Figure 8 1 Inrush current limiter circuit diagram can be used to bypass
189. or up to 640 x 480 VGA at 30 Hz 34 The controller s main purpose is to keep the display refreshed which implies writing data to each pixel continously fast enough in order to prevent flickering when updating the content This is done automatically without the need of intervention from the CPU which frees the CPU to do other work The display controller retrieves data that will be displayed on the display from a designated frame buffer This buffer must be large enough to contain information for all the pixels and twice this size if double buffering is used Double buffering is a technique which allows updating the display in a separate memory area instead of directly drawing on the screen This is useful especially if the drawing operation takes time for instance when loading a bitmap Double buffering is explained in detail in chapter 7 4 The display buffer needs only to be read only but it needs to be fast in order to supply data fast enough to the display This memory will be discussed in chapther 7 3 Allocating pins As shown in figure 4 1 on page 29 a lot of I O pins are occupied on the PIC24 due to the use of the EPMP parallel bus and the display driving lines In addition a SPI connection to the other microcontroller is needed 12C for the display touch controller UART for debugging purposes power connections and necessary connections for programming In order to keep track of all these connections and making sure no more than
190. orrect input it was not possible to cause havoc by entering erroneous data by interacting directly with the API However as noted earlier the APT returns its own special compact format instead of a more human readable and widely supported format like JSON This should be improved if the API is expected to be used Similarly the return value from the API functions should could be more descriptive than a single ASCII digit signalling an error code Lastly the config getNewAvailTypeDefVals html page which creates new data when visited should be changed GET operations should only be used to query data not manipulate data on the server Responsiveness and mobile access The previous test gave the impression of very quick loading of new pages and an overall impression of a very responsive interface This is thanks to the server being able to serve data quickly and also because of the design choice of loading all CSS and scripts on first visit After the initial load which is still barely noticeable the remaining page changes feel instant since only HTML and no external resources need to be downloaded Nonetheless the Ul design expects the user to refresh the page on a few occasions to present the updates he has done with forms This causes all external resources to be reloaded which is unnecessary This should be improved by having JavaScript automatically reload the page or only the necessary data in the background by using AJAX The
191. other TP depends on address resolution protocol ARP which in turn depends on the physical layer Only two of the protocols are interacted directly with in the OOD application HTTP in the web server and SNTP for synchronising time Two other indirectly used protocols that are not direct dependencies of HTTP and SNTP are DHCP and SSL DHCP is used to get an IP address automatically assigned in a network 68 p 488 and makes the OOD easy to set up SSL is used to secure HTTP traffic more specifically prevent passwords to be transmitted in clear text when authenticating in the web UI The need for SSL and how it is set up and used is explained later in chapter 20 6 Figure 20 2 on the facing page shows all the protocols in the TCP IP stack that are needed in order to run a web server with SSL a DHCP client and a 20 1 ARCHITECTURE 137 7 Application DHCP 5 Session 4 Transport 3 Network ARP IPv4 ICMP 2 Data link 1 Phvsical Figure 20 2 Protocol dependencies in the various OSI lavers SNTP client The dark coloured protocol names are the only protocols explicitly required and the rest are the necessary dependencies The arrows show the dependency chain and the protocols are placed in the layer they belong according to the OST model MAC is not a protocol but a sublayer of the data link layer but it shown here as a module The same goes for Ethernet which in this case is the LAN8720 transceiver Table 20 1 File
192. ould provide good support for Ethernet This frees program space it makes it possible to separate network and graphics related tasks completely but it also creates a few challenges The microcontrollers need a way to share data which gets tricky when the main storage has to be in control of one of the microcontrollers A separate memory was suggested for the microcontroller handling graphics giving it fast access to static data like fonts and GUI graphics Microchip has one product that stands out in its lines of microcontrollers the PIC24 DA series which is a 16 bit microcontroller with an integrated graphics controller It is a natural choice for the OOD The second microcontroller needs to have sufficient program memory no less than the already chosen PIC24 256 kB Among the many alternatives the more advanced models in the PIC32MX series come with 512 kB flash 128 kB RAM and an integrated Ethernet controller The model with most flash and RAM was chosen so that there will plenty of room for application code 4 2 PIC24FJ256DA210 The PIC24FJ256DA210 from now on referred to as simply as the PIC24 is a 16 bit microcontroller with 256 kB flash 96 kB SRAM USB on the go OTG support and comes with an integrated graphics controller 34 The PIC24F series differs from the other series in Microchip s 16 bit architecture by being low powered which limits their performance to 16 million instructions per second MIPS The PIC2
193. p to 255 words long and make up the following stream of packets The payload uses all 16 bits in each packet so the recipient must expect the transfer and must not try to read the type field of the data following the first packet 1 error Error packets contains an abort bit which tells the recipient whether the current transmission should be terminated The remaining bits are not yet completely determined but is currently used for storing an error code 2 status The status packet contains various bit fields specific for PIC32 and PIC24 The status fields in PIC32 will be used to tell the PIC24 that new data is available and that it should query for updates Only header packets indicate a longer transmission Status packets will always be sent when no other response is expected which helps the microcontrollers to keep themselves up to date about each other at all times Figure 21 1 on the facing page shows a sequence diagram of PIC24 querying for the name of the owner It illustrates that the PIC32 is not ready to reply the first time the PIC24 initiates a transfer hoping for a reply header The PIC24 backs off and tries again later and receives a header packet with a response to the query Being the master it is PIC24 s responsibility to wait long enough for the data to be prepared in PIC32 before retrieving it However starting the transmission too early will not cause any problems Both microcontrollers call the same periodic function
194. pricier and lacks auto MDIX support Choosing a QFN package may pose a challenge since the remaining components are to be hand soldered and QFN cannot be soldered with a soldering iron Nonethelss it is expected that methods using hot air will work Another quality of the LAN8720 that made the transceiver attractive is the good documentation and the many helpful resources available on PCB design The LAN8720 is configured and controlled in software by a driver in the TCP IP stack No configuration is needed by the user The transceiver does on the other hand require careful hardware configuration strapping input pins 5 22 LAN8720 39 nINT REFCLKO TXD1 TXDO TXEN nRST VDD1A DMIO TXN SMSC LAN8720 CRS_DV MODE2 top view a u TXP RXER PHYADO VSS RXN VDDIO RXP RXDO MODEO RBIAS RXD1 MODE1 VDD2A ES XTAL2 ES VDDCR Me LED2 nINTSEL WS LED1 REGOFF BB XTAL1 CLKIN By Figure 5 1 LAN8720 pin out to certain levels The following sections explain the connections and additional components needed for the LAN8720 to work as expected Configuration straps LAN8720 reads four configuration values based on the level of seven of the pins during reset Pull up or pull down resistors are used to set the desired configuration Figure 5 1 shows the pin out of the LAN8720 The configuration pins are the seven pins with inverted alternative meanings The four settings that need to be set are e Address RXER PHYADO pin used to
195. pt in memory at a time Widgets will be created and destroyed as pages change A state machine will be used to make it easy to build long menu chains on the OOD The state machine will support entry exit and transition actions making sure that objects are created destroyed and drawn at appropriate times No state machine implementation could be found that suited these needs so a module was built from scratch It is a relatively lightweight implementation but it still comes with advanced features It was designed and implemented as a completely separate module so that it can be used for other purposes than just embedded GUIs The source is well documented and can be found in the appendix The documentation will not be repeated here but a small introduction on how it works will be given The state machine module consists of stateMachines states events and transitions State machines have their data contained in separate objects allowing the module to operate on numerous state machines A state machine is built by the developer by creating states and connecting them by defining transition arrays This may be done either on the stack or the heap or both since states are connected by using pointers The finished state machine referred 18 3 USING A STATE MACHINE WITH GOL 129 parent group state entry state U entryAction event guard condition event GentrvAction event STATE eo gt STATE e a exitAction event N exi
196. r 10 Mbit s and 25 MHz for 100 Mbit s Around 18 signal lines are needed between the transceiver and 37 38 CHAPTER 5 ETHERNET the MAC device depending on the device A variation of MII RMIT has a reduced signal line count 10 in the case of PIC32 an instead uses a 50 MHz clock reference RMII also supports 100 Mbit s throughput Given the reduced line count RMII is a more promising candidate than MIT It will be easier to route on a two layer PCB and transceivers that supports only RMII can be found in smaller packages due to the reduced need for pins The ten signals needed are shown in table 5 1 Table 5 1 RMII signals 38 p 63 Name Description REF CLK Referece clock providing timing reference for CRS DV RXD 1 0 TX EN TXD 1 0 and RX ER CRS DV Carrier sence receive data valid RXD 1 0 Receive data TX EN Transmit enable TXD 1 0 Transmit data RX_ER Receive error MDC Management data clock MDIO Management data input output 5 2 LAN8720 Among the many transceivers available LAN8720 was chosen due to its compact size 24 pin quad flat no leads QFN due to no MII support price and auto MDIX support The price at Digi Key as of February 2013 is 1 21 USD per unit and 0 76 USD per 100 The auto media dependent interface crossover MDIX support is very welcome because it relieves the user of potentionally needing a cross over cable when using the OOD The previously mentioned DP83848C is larger
197. rder to communicate with the controller and retrieve touch events and coordinates a driver is needed Although implementations for the FT5x06 exist they are aimed for Linux kernels and would need at lot of modification to be ported to PIC24 Luckily it is a simple task to retrieve touch data from the controller only a simple register read is necessary The FT5x06 comes preconfigured for the display it is attached to eliminating 109 110 CHAPTER 16 TOUCH CONTROLLER DRIVER the need for accessing registers for set up and tuning There is also very little need to alter any of the low level settings so the driver discussed in this chapter will provide no means of reading and writing the lower level configuration registers Although support for alle five touch points will be implemented only one point will suffice for the OOD If there is a future need for reading numerous touch points the support is ready and is easily enabled Figure 16 1 on the preceding page show the three layers of the touch driver The lowest layer is the 12C driver which takes care of all the low level I C communication routines The middle layer is the core of the touch driver which sends commands and parses the results from the touch controller received from the PC driver The uppermost layer connects the touch controller and the graphics object layer GOL providing the graphics library with coordinates and events in the formats it requires By dividing the mo
198. re too time consuming and Microchip s solution seem to suit the OOD s needs The graphics library from Microchip is a part of Microchip application libraries MAL 56 which is a large collection of free software that help utilise the features of Microchip s hardware products It is developed by Microchip and released in new versions a few months apart Being tailored for Microchip s own hardware the software libraries in MAL are ready for use without any modifications or third party I O layers The remaining software library needs are discussed in their respective chapters Licenses The OOD is an academic project but it is developed so that it can still be made into a commercial product at a later point The licenses of the software used plays a major role in this Care will be taken to avoid using software with licenses that prohibit commercial purposes or require expensive royalties In this regard it is worth discussing the license of the MAL which will be used extensively in the project Microchip application libraries MAL is provided for free from Microchip s websites 56 The downloads are executable installation scripts that forces you to agree to their licensing agreements before gaining access to the source code This way Microchip ensures that users of the source code have accepted their terms of using it The software license agreement 47 p 3 6 is long and a bit hard to decipher It allows authorised use a
199. rnstyres av eieren N r professoren ma g i et rend kan han oppdatere skjermen med informasjon om hvorfor han er borte og n r han kommer tilbake Forbipasserende og bes kende kan holde seg oppdatert om n r det passer bes ke vedk ommende og professoren slipper motta anrop om sp rsm l om n r han aller hun kommer tilbake Oppgaven tar for seg prosessen fra id til prototype og inkluderer beskrivelse av problemet design av l sningen komponentvalg og PCB design utvikling av programvare og r d og forslag for videre utvikling Istedenfor bruke en embedded Linux plattform har det blitt valgt bruke mikrokontrollere med m l om teste mulighetene for TCP IP and SSL i ressursbegrensete systemer En 16 og en 32 bits mikrokontroller blir brukt til kj re en vevtjener med st tte for kryptering samt drifte en WQVGA fargebergringsskjerm med et grafisk grensesnitt Det er ogs valgt bruke Microchip l sninger fremfor produkter fra Atmel slik at Institutt for teknisk kybernetikk kan tilegne seg kunnskap om andre mindre kjente produsenter Det er ikke mulig fullf re systemet p grunn av begrenset mengde tid tilgjengelig Maskinvaren er ferdig utviklet drivere er laget og en TCP IP stakk med en modifisert HTTP tjener er konfigurert og testet Et fundament for de resterende programvarekomponentene er p plass og det er gitt r d og forslag for videre utvikling Resultatene fra arbeidet viser at det er mulig lag
200. rough the process of describing a problem designing a solution making a hardware prototype and developing software serving as a solid foundation for further work An objective was to use microcontrollers for the task and explore the possibilities of implementing embedded Ethernet networking and graphical user interfaces Adding to the challenge the target was to use Microchip products in order to learn more about solutions from manufacturers less known to the department The results show that the microcontrollers used have an impressive array of features They could easily handle a TCP IP stack with SSL3 and a feature rich GUI library The web server provided with the TCP IP stack from Microchip application libraries MAL has been heavily modified to support a FAT32 file system Testing has revealed that it is capable of providing a throughput of 550 kB s and a relatively good support for concurrent connections Encrypting the web server s traffic with SSL can be done with a throughput of 317 kB s RSA key sizes up to 2048 bits are supported providing sufficient security RSA decryption on the 32 bit microcontroller took as much as three seconds but with the aid of storing SSL session data the negative impact of the overhead can be reduced Overall thanks to improvements to the web server the embedded network implementation proves good and fast enough for systems aimed for few users The solution is perfectly suited for hosting a web interface
201. s openssl x509 req days 3650 in oodCert csr signkey oodCert key out oodCert crt Parse the generated key retrieving the p and q RSA primes with their pre calculated dp d mod p 1 dg d mod q 1 and giny 47 mod p values and store them as five arrays with the ASCII hex pairs reversed converting from big endian to little endian openssl asniparse in oodCert key tail n5 awk print 7 cut b 2 parse pl The parse pl script does the reversing and adds C syntax The script can be found in appendix A Save the byte representation of the certificate as an array called const uint8_t SSL_CERT First run openssl asniparse in oodCert crt out oodCert crt bin Inttps www openssl org Debian package openssl 158 CHAPTER 20 TCP IP STACK and open the binary file using a hex editor for example jeex copy the contents to the certificate C source file and convert the numbers to hex digits in the array 6 Add a certificate length variable const uint16_t SSL CERT LEN sizeof SSL CERT The example stores all the arravs in program memorv due to the const kevword but thev can also be stored as non const This would make it possible to change the kevs at run time and opens for the possibilitv of letting the owner upload new kevs and certificates See appendix A for the two C files containing the certificates alreadv made along with the files used to generate them In order to let th
202. s ID Type Colour Title Description 0 Unknown Gia Unknown Availability not set 1 Unavailable eae Busy Please do not disturb x 2 Available E58 Available Please disturb A 3 Unavailable ES Atlunch Mv lunch time is sacred x 4 Unavailable Giai Athome Working at home x 5 Unavailable EN Ina meeting Please do not call me 6 Available EL 4 Present Busy but come in if you really must x 10 Unavailable HEJ On holiday Inthe Caribbean no calls use e mail Ej 6 Add new Figure 23 4 Availability type configuration Figure 23 4 shows the completed web interface for configuring availabilities A few availabilities are added in order to illustrate the purpose of having multiple types of availabilities not just unavailable and available The colours chosen in the example do not necessarily match logically with the description but this is nontheless up to the owner to use as he pleases All the fields apart from the ID can be changed by single clicking tapping on the field A library called Jeditable is used to replace the text with an input textbox which will post the changes to the server when a user has finished edited the text Blinking CSS effects will indicate whether the request succeeded and a pop up will provide http www appelsiini net projects jeditable MIT license 23 5 OUTLINE OF A PAGE WITH JQUERY MOBILE 179 more error feedback The table is best viewed on relatively wide screens like mobile
203. s linkers and debugging tools In order to download the software to the microcontrollers special programming hardware is also needed This chapter will introduce the necessary software and hardware needed to start working with Microchip microcontrollers An introduction will also be given to MAL and how to set up a local network for working with the OOD The operating system used is Debian but all of the essential tools are also available for Windows and OS X 14 1 Microchip compilers and IDE Microchip s compilers are based on GCC Although the GCC compilers are GPL licensed Microchip do not publish the source code of their compilers and they require one to buy compilers with optimisation enabled Whether this practise is allowed is debatable but nonetheless it is possible to get Microchip s compilers for free limited to one level of optimisation The free versions will be used in this thesis Since both 16 bit and 32 bit microcontrollers are used in this work two compilers are needed XC16 and XC32 They can be downloaded from microchip s website http microchip com Microchip provides an integrated development environment IDE called MPLABX which comes with lots of helpful features for developing for their microcontrollers MPLABX will be used during development mainly for making makefiles and downloading code to the microcontrollers MPLABX can be downloaded from Microchip s website The tool used to download code to the
204. s needed from the TCP IP stack File name Description HTTP2_FatFS c _HTTP2 h HTTP server ARCFOUR c h RC4 algorithm used to encrypt message streams in SSL ARP h For IP address resolution BigInt c h Used for mathematical operations on big BigInt_ helper PIC32 S integers used in the RSA algorithm needed for exchanging kevs in SSL DHCP c h DHCP client DNS c h Used to look up DNS host names and return IP addresses Used to resolve host names provided by user for SNTP pool servers 138 ETHPIC32ExtPhy c h ETHPIC32ExtPhyRegs h ETHPIC32ExtPhySMSC8720 c h FileSystem c h HardwareProfile h Hashes c h Helpers c h ICMP c h IP c h MAC h ETHPIC32IntMac c Random c h RSA c h SNTP c h SSL c h SSLCertificate c StackTsk c h TCP c h TCPIP h TCPIPConfig h Tick c h CHAPTER 20 TCP IP STACK Ethernet transceiver driver A layer between the web server and the file system defining I O functions Definitions and macros for clock frequen cies and RMII addresses MD5 and SHA1 hashing algorithms used by SSL Miscellaneous functions including ran dom number generators Base64 encod ing decoding and string manipulation functions Used by the ICMP server mainly to reply to ping requests Used for parsing and manipulating IP headers Media access control MAC Providing random numbers used by SSL Public key encryption algorithm used for exchanging keys securely in SSL SNTP SSL Arrays containin
205. s render the device rather useless given that the display is one of the most important features The GUI library acts as tools and a framework for making menus It does not provide mechanisms to switch between menus so another layer is built on top of the GUI core This layer is simply a state machine which switches between menus depending on user input and signals from the PIC32 When a menu is changed its GUI elements are destroyed new elements are created and then drawn The microcontrollers both have a copy of a module that handles the communication between them A client server model application structure is used where the PIC32 is the server and PIC24 the client The PIC24 will frequently ask for a status update whereupon it acts with requests for new data when something has changed This can for example be an update from the web interface or a new availability status becoming active since since its start timestamp is in the past 13 1 Operating system Although one of the main design goals is to use a more primitive approach than using an embedded Linux there are still many simpler and smaller operating systems that can be used One of the benefits of using an embedded OS RTOS is the ability to use threads with customisable scheduling policies thread priorities and stack sizes With the broad selection of RTOS implementations there are few downsides of using one The main challenges are finding an RTOS that has a compatible licens
206. s that can be served at a time Another big limitation is the lack of support of common gateway interface CGI and server side scripting languages like PHP Java Perl ASP or Python In order to compensate for this Microchip s HTTP server has a method of replacing text in HTML files with dynamic variables which will be discussed later How the server works The HTTP server consists of the files HTTP2 c and HTTP2 h the filenames in the FatFS modified version are named HTTP2_FatFS c and _HTT2 h It is initialised from StackInit and it handles requests when called regularly via StackApplications Figure 20 3 on page 143 shows HTTP server s state machine Each connection has its own state variable so that when the HTTP server is given a chance to run its periodic callback function it loads a connection one by one and processes the request from where it last stopped A typical HTTP request for the root directory of a web site starts with GET HTTP 1 1 68 p 705 GET is one of the defined methods in the HTTP protocol The only other method implemented in the HTTP server is POST which is used to send data to the server The request is parsed in the PARSE REQUEST state If the request is not supported or if the requested file is not found the server skips further processing and responds with an error response The request headers are parsed in the PARSE HEADERS state followed by an authentication step if the requested
207. s therefore not a great level of detail in the chapters discussing the electronics side of the OOD It is expected of the reader to have good knowledge of the programming language C a basic understanding of hypertext markup language HTML cascading style sheets CSS JavaScript and Linux and basic knowledge of electronics The reader is also expected to have a basic understanding of TCP IP and Ethernet There is no separate chapter on background theory Necessary explanations will be given where needed and more extensive background theory can be found in 66 Due to the great extent of the project there will no time to finish the OOD as it is presented in the specification However there will be sufficient detailed studies of all the vital components of the system in order to make assesments of the suggested design The focus is directed towards making a solid foundation for further development rather than trying to implement the whole system 1 3 Outline of the thesis Before the implementation is discussed a small repetition from the original design 66 is given followed by necessary modifications and improvements Based on this a more detailed specification is made which is used in the following parts to implement hardware and software The project is large so it is necessary to shorten and exclude certain parts Some of the chapters are very detailed like the chapter on TCP IP because it is a part of the main goal to explore the su
208. sary The callbacks can use this pointer to store as much state data as they need by using a struct on the heap See appendix A ood pic32eth X http avail Type c for how this technique is used in practise GET and POST processing In order to provide an interactive web site the web server needs to be able to receive queries commands and new data and convert them into actions on the display and I O operations on the file system The HTTP server supports both GET and POST requests which to a certain extent are interchangeable They can both send an URL encoded string consisting of name value pairs separated by ampersands amp When using GET these name value pairs make up the query string and is a part of the URL added after a question mark but when using POST the data is in the request message body 68 p 704 Since the HTTP server only has a limited buffer for parsing request headers using POST is recommended By using POST an arbitrary amount of data can be sent to the server which makes it possible to send even large files The web server calls the user supplied function HTTP_IO_RESULT HTTPExecuteGet void 20 5 HTTP SERVER 149 to process GET query strings and HTTP_IO_ RESULT HTTPExecutePost void to handle POST requests It is expected of the user to manually fetch the data from the receive buffer when POST is used but the web server provides some convenience functions to look for names and values and retrieve the U
209. sit a closed door and professors will not have to answer calls all day explaining their absence The thesis starts with describing the out of office problem contin ues with presenting a design of a solution the process of making a prototype with necessary hardware and software and suggestions for further development The project will use microcontrollers in order to test the capabilities of resource constrained systems A 16 bit and a 32 bit microcontroller will run a full TCP IP stack with SSL support for a web interface and drive a WQVGA LCD display with capac itive touch and run a graphical user interface In order to broaden the Department of Engineering Cybernetics s experience with solu tions other than those from Atmel Microchip s microcontrollers and development tools will be used to implement the system Time will not permit completing the whole system A hardware pro totype is made complete with necessary drivers and a working HTTP server customised for hosting an interactive web interface A foun dation for the remaining software is implemented with suggestions on how to finish the system The results show that it is possible to use microcontrollers to run an embedded GUI but that it is cumbersome and comes with challenges concerning encoding and fonts The web server can deliver a through put of 550 kB s using a FAT32 file system on a microSD card which is sufficient for a single user web interface It is less ideal
210. solution was chosen to match the estimated viewing range and the limitations of the driving microcontroller The PowerTip model was chosen mainly because it was found as a ready to use development kit for the PIC24FJ256DA210 After several months of development the resistive touch screen was found to be troublesome to use with finger tips Resistive touch overlay is a cheap input method that works well with pointy objects but when used with flat finger tips touches are sometimes not registered and the accuracy is limited With a small display it is necessary to have an input method with a good accuracy in order to keep GUI elements like buttons as small as possible The first hardware to be reevaluated from the original design was the display The new candidate is a display with almost exactly similar specifications but with a capacitive touch glass overlay instead of a resistive film overlay The device is a Newhaven NHD 4 3 480x272EF ATXL CTP Its touch controller is a FocalTech FT5x06 preconfigured for the display and accessible through PC The display comes with a standard 24 bit RGB bus and display control lines and touch controller signal and power lines The display is connected using two flat cables and external circuitry is needed for the LED backlight 7 1 Display capacitive touch controller The Newhaven display comes with an integrated touch controller IC It is mounted on the flexible PCB attached to the display and its pins can
211. ssage he or she has not yet written down or a request to book a meeting or visit The visitor can use the display to notify the office worker about their visit or book a meeting with an interactive booking menu that shows when the occupant is occupied or out of office in the following hours and days e Before seeking the office a visitor can look for the office worker s availability online If the OOD is connected to a larger monitor showing a list of the department s employees their availabilities can be shown here as well Then it would not be necessary to go to the office worker s door to see whether he or she is present or occupied e In environments where the employees frequently change offices no new name signs need to be ordered The name and portrait on the display can easily be changed 2 2 Main components The main components of the OOD are considered to be the three interfaces and the hardware and software that make them up What is expected of these interfaces is described in the following sections Display and GUI The display is the most important part of the OOD It serves as a replacement for a name sign a portrait and more importantly it serves up to date information about the availability or absence of the person whose name is on it In its normal state at the root of the menus of the GUI the display shows the following key data e Name and title e Portrait if needed 12 CHAPTER 2 SPECIFICATION AND SY
212. stem needs write access in order to store configuration data and calendar entries Display and frame buffer The display suggested in 66 is a thin film transistor TFT colour LCD display measuring 4 3 It has a resistive touch overlay and was chosen mainly for the fact that it came with an adaptor for the development boards used The display type resolution and dimensions were deemed acceptable for the OOD The resistive touch overlay was found to be a bit user unfriendly but at the time there were no capacitive touch solutions available A display similar to that of the one chosen in 66 PowerTip PH480272T_005_111Q should be used but preferably with capacitive touch The frame buffer needs to be a RAM with fast enough access times to keep the refresh rate unnoticeable to the user The capacity must hold at least twice the amount needed to store all the pixel data for the display This enables the display controller to utilise double buffering Microcontrollers The microcontrollers suggested in 66 were carefully chosen and proved to be good candidates Two microcontrollers were needed in order to share the two great tasks of driving the display and handling Ethernet between them Between them the microcontrollers need to e Interface with an Ethernet controller or transceiver and provide an acceptable speed Drive the chosen display at a frame rate high enough to avoid flickering during updates e Have enough program memor
213. sting role as a web server The web UI sends queries for retrieving and updating data The display GUI will not be much different from the UI in this regard A protocol is needed on top of SPI and is developed from scratch It utilises the possibility of sending words 16 bits at a time and the full duplex capabilities are utilised to always send useful data even when the device is busy receiving data The basic packet format of the protocol is shown in table 21 1 The first Table 21 1 Inter microcontroller communication packet format O 1 2 3 4 5 6 7 8 9 10 11 12 18 14 15 Type Packet type specific data Header packet 0 Type Query Length data 0 255 words Error packet 1 abort error Status packet 2 Microcontroller specific status packet two bits of the first packet in any transmission is used to tell what kind of packet has arrived and how to handle the remaining 14 bits 161 162 CHAPTER 21 INTER MICROCONTROLLER COMMUNICATION 0 header A header packet indicates the start of a transmission that may contain numerous segments determined by the length field The first 5 bits tell what kind of query or response the packet is An example is a query for the owner s name Type_name The next bit if true indicates that the packet is a query Queries are normally of length 0 but responses always carry data The payload can be u
214. style scheme scheme should be used The button will be drawn on the next call to GOLDraw which is the only graphics library function that needs to be called repeatedly in order to perform GOL drawing operations when necessary All widgets are drawn using a set of colours and a preset font defined in style schemes Unless an explicit scheme is chosen for a widget the default scheme is used More details about style schemes can be found in the library s help document 45 p 338 GOL implements a message system from which only touch events are going to be used in the OOD GUI In chapter 16 3 the touch driver s GOL message 167 168 169 170 171 172 173 174 175 176 177 178 126 CHAPTER 18 GRAPHICS LIBRARY ood pic24gfx X main c Perform any pending drawing operations GOLDraw GOL MSG touchMsg Get updated touch data if touch_getTouchData amp touchMsg Finish all pending drawing operations before sending touch data to GOL message handler while GOLDraw GOLMsg amp touchMsg d Code listing 18 3 Handling touch events and GOL draing in main interface was briefly explained When a touch event is retrieved from the touch display it can be delivered to the GOL for processing by using GOLMsg This can however only be done as long as GOL is not busy drawing In order to ensure that messages are only passed to GOL when it is ready the return value from GOLDraw is used whi
215. sue that made developing web pages more difficult was the limitation of not being able to send data from the function processing the POST request After processing the POST request the sender needs to be informed whether the request was accepted or whether any errors occurred The reason why data cannot be sent during POST processing is partly because the socket buffers are optimised for reception When the socket buffers are lated optimised for transmission any data put in the socket in the mean time is lost Although this could be remedied the main problem is that sending data at this point would corrupt the order of the response to the client The headers need to be served before the message body Since there is no easy way of rewriting the server to handle the need to send data from the POST processing functions another approach was taken 20 5 HTTP SERVER 151 The files requested in POST requests all contain a single dynamic variable and nothing else no HTML A variable added to the HTTP_CON connection state is used to store the current form status It is set in a form processing function and read from the callback that is associated with the dynamic variable formStatus The callback reads the form status variable from the current connection and writes it to the socket This processes is displayed in detail in figure 23 1 on page 170 and further explained in chaper 23 As with the dynamic variable callback functions the POST processing
216. t will not handle cases where one of the microcontrollers freezes rendering it incapable of updating its transmit buffer This can be remedied by using an SPI RX interrupt to always put a sane value in the buffer Apart from sending each other frequent status updates the microcontrollers should challenge each other to ensure that they are alive This could for instance be implemented by sending a payload which the recipient should perform a mathematical operation on and send back If the result checks out the microcontroller can be considered alive The source code for the inter microcontroller communication module can be found in appendix A 23 24 25 26 27 28 Other modules and software In addition to the already mentioned software modules there are a number of smaller software components essential for the OOD They will be given brief introductions in this chapter 22 1 Settings ood pic24gfx X config PICConfig h _CONFIG1 JTAGEN_OFF amp Disable JTAG port FWDTEN_OFF Disable watchdog GWRP OFF amp Disable code flash protection GCP_OFF Disable program memory protection DE Code listing 22 1 Excerpt of the PIC24 configuration Two different processes are needed to configure the OOD on power up First the microcontroller needs to be configured It needs to be told that it will be using a crystal as its clock source PLL must be enabled and all memory protection must be turned off This is done by initi
217. tAction event exitAction event JS guard condition event GentrvAction event ERROR ra e gt S jo c o o b action event STATE final state Figure 18 4 State machine features to by its initial state is given to stateM _init along with a pointer to a state serving as an error state The error state is a final state a state with no transitions that will be visited by the state machine if an error occurs The errors picked up by the state machine are NULL states and transitions that do not point to a new state The function builds a stateMachine object that must be given as an argument to other state M__ functions The state machine is run by passing events to it with the function stateM_handleEvent Figure 18 4 aims to illustrate the features of the state machine module It shows that states can be grouped in group parent states Parent states are useful if all the grouped states share a common transition States may be unconditional or have a guard Guards are functions operating on a condition stored in the transition along with a passed event If they return true the transition will be 130 CHAPTER 18 GRAPHICS LIBRARY executed If the transition has an action defined it will be called before entering the new state All states may have entry actions and exit actions The state machine is fully implemented but not yet used to build a GUI The way it is intended
218. te seen in listing 23 1 as data theme a When the page is loaded by Query Mobile the attributes are used to load the needed CSS rules for the theme Five standard themes are included in the CSS supplied with the library but themes can also be customised by using ThemeRoller jQuery Mobile is designed so that it is very easy to write Custom data attributes are used extensively to include library components and configure them 1This is personal perception and may not apply for others 2http jquerymobile com themeroller On A UOU N b N 10 11 12 14 15 16 17 18 19 23 5 OUTLINE OF A PAGE WITH JQUERY MOBILE 175 ood pic32eth X html config index html lt DOCTYPE html gt lt html gt lt head gt lt meta charset utf 8 gt lt meta name viewport content width device width initial scale 1 gt lt title gt Configuration lt title gt lt Needed if the page is accessed directly and not loaded with AJAX gt inc config includes html goa gt lt head gt lt body gt lt div data role page id configMainPage gt lt div data role header data theme a gt lt a href data icon back data rel back title Back gt Back lt a gt lt hi gt Configuration lt h1 gt lt div gt lt div data role content data theme c gt Code listing 23 1 Typical start of a HTML5 page in the web UI The page will do very little until JavaScript is loaded so that these attr
219. that need a 100 MBit s RMII Ethernet transceiver An issue with the type of parallel flash chosen is that bits can only be set to 0 once after erasing memory which sets all bits to 1 26 p 18 This may not be an issue if the parallel flash is used solely for long term storage of static GUI graphics and fonts but it makes it more difficult to use the remaining storage for other purposes A flash without this restriction should be considered for further development if this is important The memory devices resistors crystals capacitors and connectors were all selected from the available selection from Farnell Due to Farnell s limited selection on certain component ranges less optimal components had to be chosen in certain cases This mainly only affected the footprint and size of components Numerous components were also far dearer from this supplier compared to alternatives like Digi Key and Mouser For further development it is advised to use suppliers with greater selection and better prices in order to save expenses and avoid compromises 11 2 Design flaws and improvements The component placement design error may seem like an error that could easily avoided However with only a two dimensional representation of the PCB in the design tool it can be easy to confuse the upper and lower layer With an occasional review of the board in a 3D representation this error would very likely not be missed Eagle does not support a 3D view but th
220. the GUI library However the development boards have been used to test the functionality of the library in order to ensure that it has the capabilities needed to implement the main page Figure 26 4 shows a mock up of the main page on the PowerTip development board It shows a successful rendering of a bitmap fonts in various sizes a gradient and a button which will take the user to a new screen Replacing the PowerTip display with resistive touch with a Newhaven display with capacitive touch worked flawlessly both on the development board and on the OOD hardware The touch controller driver has not shown any signs of problems and the display worked as expected Discussion and further work The out of office display is not yet a finished concept The idea behind it has been thoroughly discussed and the results presented in this thesis is one of many possible suggestions on how to provide a solution The choice of using microcontrollers was done in order to explore the possibilities and limitations of implementing networking and graphics on resource constrained systems The results has shown that a lot can be done but it comes with its limitations and requires a lot of work that could be abstracted by using higher level solutions 27 1 Development using Microchip microcontrollers One of the objectives of the thesis was to gain more knowledge on non Atmel microcontrollers and in this case get to know Microchip s products A microcon tr
221. the circuit Some of the components are not intended to be populated but their footprints are included for experimental purposes The way the circuit works falls out of the scope of this thesis The component values chosen based on the instructions in 64 are R8 100 Q R10 100 kQ C4 0 1 pF 8 2 PoE controller and DC DC converter Apart from the inrush current limiter the rest of the circuitry remain unchanged as it was presented in the PoE PD prototype in 66 The original design had a PoE class and the power supply dimensioned for an initial current draw estimate of a total of 700 mA In order to see if this enough to supply all the components chosen the maximum ratings of all the components need to inpected Table 8 1 on the next page show that about 400 mA is the expected maximum current draw This is well within the limits of the original design The full circuit diagram of the complete PoE power supply circuit can be found in sheet 2 in appendix C 1 PoE classification determines how much power a PD is allowed to consume see 66 ch 5 1 l Assuming 100BASE TX with constant traffic 2May vary from card to card the card used is a Samsung HC class 2 4 GB 3Display logic touch controller and LED backlight 8 2 POE CONTROLLER AND DC DC CONVERTER 63 Table 8 1 Maximum operating currents per device 22 p 6 26 p 32 34 p 374 39 p 185 46 p 65 40 p 6 67 p 5 Device I mA SRAM 35 Parallel flash 20 P
222. the driver needs to know how to represent the characters in matrices of pixels It will need font resources for all the combinations of font types and font sizes used in the GUI A font may take a considerable amount of space and cannot be put in the microcontroller s program memory if there are many of them Since the OOD should display both a large name as well as small information at least two fonts are needed The parallel flash was chosen to accommodate both the need for lots of storage space and efficient access for the GUI Graphics Resource Converter version 3 29 06 File Project Help ela BEl lalals 8 Compres Convert Label Type Size Bytes Font Name Point Size Monospaced 12 Mathjax Typewriter 2179 Mathjax WinChrome 10 Mathjax WinlEG Z 11 Monospaced z ji Style Bold Extended Glyph Italic Anti Aliasing Font Unicode Ranges Basic Latin 7 Preview Font height 15 pixels Converted Character Range Starting Character 32 Ending Character 127 ki Font Filter Comment Block Figure 18 3 The Graphics Resource Converter Fonts and graphics are converted into a format the primitive drawing layer understands by using a tool called Graphics Resource Converter GRC which 128 CHAPTER 18 GRAPHICS LIBRARY is included with MAL The font family size style an
223. timer in order to generate a delay EthPhyNegotiationComplete and 594 595 596 597 598 599 600 601 602 603 604 605 15 1 HOW THE LIBRARY WORKS 103 EthPhyReset in ETHPIC32ExtPhy c the core timer dependency in FatFS has been removed No replacement has been made so there is currently no timeout functionality in the FatFS I O layer This has yet been a problem but it should be fixed in order to make the system more robust Removing the interrupt routine also removed the I O layer s ability to detect card insertion removal This has been resolved by implementing a new function that checks for a state change at the appropriate I O pin accounting for bouncing issues It is not included in the FatFS module but it calls a new function in the I O layer that sets the appropriate status bits when the card is inserted and removed Listing 15 4 shows the two new functions in mmcPIC32 c and listing 15 5 on the next page shows the routine monitoring the card detect I O pin RE9 Bouncing problems caused by the mechanical card detect switch is effectively eliminated by waiting a relatively long time 100 ms before asserting the state change The initial card detect state is set at line 300 The new asserted state is set at line 314 disk_notifyCDChange prevState sets the card detect state bit in the FatFS I O layer If an I O operation is performed while the SD card is absent the operation will be silently aborted In order to preve
224. ting a network time protocol NTP and dynamic host configuration protocol DHCP server for testing A simple script for setting up the Ethernet interface and adding a few routing rules is shown in listing 14 1 This assumes a Debian like system The script adds the address oodDev eth2 inetDev eth0 sudo ip addr add 10 10 10 10 24 dev oodDev sudo sysctl net ipv4 ip_forward 1 sudo iptables t nat A POSTROUTING s 10 10 10 0 24 o inetDev j MASQUERADE sudo iptables A PREROUTING t nat i inetDev p tcp dport 80 j DNAT to 10 10 10 11 sudo iptables A PREROUTING t nat i inetDev p tcp dport 443 j DNAT to 10 10 10 11 sudo ip link set oodDev up sudo dnsmasq Code listing 14 1 Script to set up a local network 10 10 10 10 to the network interface used for the local network enables IP forwarding and adds a few rules which will make the OOD accessible through the computer s primary network interface This makes it possible to use a mobile phone to access the OOD s web server by acessing port 80 and 443 on the development computer The rules assume that the OOD always has the IP address 10 10 10 11 dnsmasq is used as a DHCP server Setting up dnsmasq is 14 2 SETTING UP A LOCAL NETWORK 95 easy by following the program s documentation In order to have the development machine act as a NTP server which will help avoiding excessive traffic to the global NTP servers the following line is added to etc ntp conf
225. transciever is necessary Finding a TCP IP stack with support for encryption SSL TLS without having to pay expensive licenses has also proved to be difficult Microchip s stack provides SSL support and requires no fees for commercial applications There are however issues with the license for the TCP IP stack which is the same license that 135 136 CHAPTER 20 TCP IP STACK applies for all the components of the MAL As mentioned in chapter 14 1 the source code cannot be redistributed due to the requirement of all third parties needing to agree to the license 47 p 3 6 The TCP IP stack only supports Internet protocol version 4 IPv4 and not Internet protocol version 6 IPv6 Since the IPv4 address pool is depleted 36 it would be wise to support IPv6 in order to make a system that is ready for the future Although the current stack version does not support IPv6 the next major version currently only available as a beta release supports both IPv4 and IPv6 56 With this in mind the OOD will support only IPv4 until the new stack is released in a stable version at which IPv6 support may be added 20 1 Architecture Ethernet Figure 20 1 Architecture of Microchip s TCP IP stack 47 p 137 The MAL TCP IP stack consists of modules and layers with a structure that coincide with the OSI and TCP IP reference models 68 ch 1 4 2 Figure 20 1 shows the architecture as stacked layers depending on the layer beneath one an
226. uctor flat cable from the display to the 64 pin display connector on the PIC24FJ256DA210 development board In addition a LED backlight power circuit is needed boosting 3 3 V to 19 2 V for the twelve LEDs in series providing backlight for the LCD 67 Lastly power for the display s internal LCD driver and the touch controller together with 12C signals need to be routed from a 1 0 mm pitch 6 conductor flat cable Figure 7 1 PCle x4 PCB connector The display connector used on Microchip s development boards is a PCle x4 connector with 32 pins on both sides of the PCB The connector is shown in figure 7 1 The needed male x4 connector can be made simply by using copper pads on the edge of the PCB and accurately trim the edges LED driver design A series of 12 white LEDs rated for maximum 40 mA 67 is used for backlight in the Newhaven display Since the LEDs are placed in series a total of 19 2 V is needed 67 and needs to be generated from the 3 3 V supplied from the development board Although this voltage could be supplied externally it is chosen to add a boost converter for two reasons 7 2 DISPLAY PROTOTYPING ADAPTER 51 1 Only one lab power supply is needed 2 The final design would need a boost converter so it is a great opportunity to test a solution before using it in the final design The chosen circuit is a DC DC boost converter using a MCP1650 750 kHz boost controller The design is greatly influenced by a LED driv
227. ue is stored in PMDIN1 The rawRead function in listing 17 2 illustrates this procedure Writing is done similarly as seen in the rawWrite function The casted address line requires some explanation e The address of the flash address integer told to the compiler to refer to and EDS address in listing 17 1 is added together with an unsigned 32 bit address offset integer e The result is casted to a volatile unsigned 16 bit EDS pointer e The resulting pointer is dereferenced with the intention of accessing the memory location of address in the external memory The EPMP module does the necessary work behind the scenes to translate the address and control the I O lines between the chips 17 2 EPMP BYPASS MODE 119 The previous examples covered reading and writing to addresses in the flash Retrieving data from the flash is straightforward and only requires a raw read as previously mentioned A write however requires a series of write commands consisting of various commands that will set up the chip to enter program mode This complicated procedure makes sure that it will be very difficult to write to the flash by mistake The ONFI specification defines the commands needed to enter program mode These commands are the same for both flashes tested in the thesis After executing the necessary commands and writing the data the datasheet recommends waiting for the program operation to finish Afterwards two sequential reads to same
228. uld potentionally speed up the encryption when using SSL with the hypertext transfer protocol HTTP server The major drawback with the ENC624J600 is the chip size 10x10x1 mm TQFP for the 64 pin package and the need for many address and data lines in order to provide good data throughput There was no conclusion in 66 to which of these alternatives that was most suited Considering the use of a 32 bit microcontroller with MII RMII support choosing a MII RMII capable transceiver looks like a good option Microchip s TCP IP stack performance table 14 shows that using a PIC32 with a MII RMII Ethernet transceiver by far outperforms the other two options Another benefit of choosing a MII RMII transceiver is the good selection of components since they are popular and both very small and cheap transceivers can be found The only drawback with choosing this solution is that the transceivers do not include RX TX buffers which must be provided by the microcontroller However this is not a major problem given the 128 kB of RAM the PIC32 microcontrollers can offer 5 1 MII and RMII The media independent interface MII provides an interconnection between the MAC sublayer and physical layer entities and between physical layer and station management enteties 25 p 1 It supports both 10 and 100 Mbit s data rates and uses four bit nibble wide transmit and receive paths It uses a single clock reference for for both TX and RX which is 2 5 MHz fo
229. ures including an auto router e It runs on Windows Mac and Linux 67 68 CHAPTER 10 PCB DESIGN AND ASSEMBLY e It is popular and has a large community which means that there are many resources for libraries and help There will be given no information about how to use Eagle since there are many resources online 10 2 Finalising circuit The main portions of the circuit diagrams have been presented and discussed in the previous chapters The missing details that have not yet been discussed are the LEDs testpoints and buzzer Sheet 4 in appendix C shows the LEDs and testpoints The LINK_ LED and 100M_ LED are controlled by the Ethernet transceiver and shows link activiy and 100BASE TX 10BASE T status They are sourced by the LAN8720 and connected to ground The remaining LEDs are added for testing and debugging purposes and have not been assigned a final purpose The exception is DHCP_OK which will be used to indicate network status These LEDs are connected to VDD and sinked by the microcontrollers All LEDs have a current limiting 330 2 resistor A few testpoints are added for debugging 3 3 V GND PoE rectified 47 V and PoE GND PoE GND is not the same as GND The PoE controller connects the grounds when it has completed requesting power and the grounds are still not equal until the inrush current limiter is done The buzzer is added to the PIC32 and its indended purpose is to give audible feedback when ID cards are read by th
230. ut The throughput for one user was measured using siege with ten repeti tions siege v c1 b r10 http 10 10 10 11 test jpg The result is a very consistent 550 kB s which is considered very good It is only 68 kB s away from the raw file I O read speed 196 CHAPTER 26 TESTING AND RESULTS Multiple connection throughput The web server is supposed to handle multiple clients but with only one core only one client can be handled at a time The rest will be queued and handled in a round robin fashion although with no well defined time slots The test in this section will tell how much effect an extra connection has on the overall throughput A test similar to the previous was performed with an increasing number of concurrent users up to the defined maximum set to 10 in chapter 20 2 The results are shown in table 26 1 Table 26 1 Multiple connection throughput results Users Throughput Concurrency Shortest Longest kB s transaction transaction 2 520 1 77 09 09 11 88 3 530 2 68 14 55 17 45 4 520 3 59 19 02 23 77 5 540 4 58 25 49 28 70 6 540 5 57 31 10 34 45 7 530 6 01 31 87 40 80 8 530 6 71 31 94 46 95 9 520 7 51 32 80 53 25 10 530 8 30 33 54 58 49 The results include the throughput concurrency which is siege s wording for average number of simultaneous connections and the shortest and longest transaction duration in seconds The results show that the overall throughput is not affected by multiple co
231. ve drawing layer This layer implements basic rendering and drawing functions like drawing text lines gradients rectangles circles and bitmaps Graphics object layer GOL This layer implement objects or widgets which are stateful objects that may change appearance based on interactions All objects are created and kept in a global linked list as illustrated in figure 18 2 Usually only visible objects related to the current menu page exist at a time A message interface accepts messages events from the application layer and passes them to all the objects in the linked lists If a touch message is passed and if its coordinates are within the drawing area of a widget the widget changes state and possibly appearance Application layer The application layer is the user provided code This code must create all the widgets and initially draw them create and pass messages events to the GOL message interface and destroy objects when they are no longer needed p eennnncocccnccccnccnccccncncccncn crac cr rr rro rr Object O Object 1 Object n NULL Current page Figure 18 2 Currently active GUI objects chain in a linked list The widgets provided by the library should fit most needs and includes buttons check boxes dials meters editing fields list boxes pictures progress 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 18 1 CONFIGURATION 123 bars radio buttons and sliders The only thing the
232. ver is located in ATTP2_fatFS c patch Follow these steps to apply the patch 1 Download MAL version v20113 02 15 and install it 2 Enter the PIC32 project directory ood pic32eth X and copy the MDD version of the web server adjust path to MAL cp microchip_solutions_v2013 02 15 TCPIP Demo App MDD HTTP2_MDD c 3 Apply the patch using the tool patch use the full path to the patch file patch p1 lt HTTP2_fatFS c patch 4 Rename the file mv HTTP2 MDD c HTTP_FatFS c A 3 FatFS read test In order to compile the FatFS read test project two files from MAL need to be copied into the project folder Hashes c from microchip_solutions_v2013 02 15 Microchip TCPIP Stack Hashes c Hashes h from microchip_ solutions v2013 02 15 Microchip Include TCPIP Stack Hashes h lhttp microchip com mal Pin allocation tables The following pages contain pin allocation tables for the microcontrollers used PIC24FJ256DA210 and PIC32MX695F512L Note that the pin misconfiguration error for the buzzer is fixed in the table for PIC32 217 PIC24 pin allocation Pin Functions Function used Purpose Purpose details Alt function Comments Moveable 78 RP22 PMBE0 CN52 RD3 RP22 Debug UART Debug UART TX Yes 74 SOSCO SCLKI T1CK C3INC RPI37 CNO RC14 RPI37 Debug UART Debug UART RX Yes 20 PGEC3 AN5 C1INA VBUSON RP18 CN7 RB5 RP18 Display Backlight PWM Yes 1 GCLK CN82 RG15 GCLK Graphics 6 RPI38 GD0 CN45 RC1 GDO Graphics 8 RPI40 GD1 CN47
233. ver pateh rere au ede ded MAE NEN a B 216 A 3 FatFS read test 22222 Coon nn 216 B Pin allocation tables 217 C Schematic circuit diagrams 225 D Bill of materials 235 1 1 2 1 2 2 2 3 2 4 2 5 3 1 3 2 3 3 3 4 4 1 4 2 4 3 4 4 4 5 5 1 5 2 5 4 6 1 6 2 7 1 7 2 7 3 List of Figures A simple out of office system 2 0 0 00 3 The OOD mounted next to an office door 9 The OOD s interactions 020000002000 10 Main sections of the default menu page 12 OOD in a plastic housing with expected dimensions 18 The design process 2 1 eee ee eee 20 The PIC24FJ256DA210 development board 24 The PowerTip display development board 25 The PIC32 development board 0 25 ENC28J60 development board 0 4 26 microSD development board 2 22 2 2 nn nn 27 All the components in the ODD and how they are connected 29 PIG2AB architecture 2 4 2 2 0208 u a ee a 32 Recommended minimum connections for PIC24F 34 PIC32MX architecture 2 222 En 00002 ee eee 35 Recommended minimum connections for PIC32 36 LAN8720 pin out 2 ee 39 LAN8720 power circuit diagram 40 LAN8720 circuit diagram RMII and LEDs 41 Height of the TM25RS 8P8C connector 42 microSD catd pinout a Sicana 2er ee ee a 45 microSD car
234. very capable and it is not necessary to use a full blown operating system for web hosting and GUI However the complexity of these systems combined demands a lot of work to provide results Results that could be implemented a lot faster and easier on an embedded Linux system Common web servers like nginx or Apache can be used for creating stable and configurable hosting environments with support for scripting languages like Pythong or PHP This would simplify web development and it would be easier to upgrade the system at a later point GUls can be developed much easier by using popular frameworks like Qt or GTK Using an OS would also eliminate or reduce encoding issues and eliminate the need for generating font data for all sizes and characters needed on the display The OOD application appears to be so complex that it should be reconsidered whether using microcontrollers is the best choice It is possible to make it all work with the tools and software provided but is it worth the effort And more importantly how easy is it to maintain and upgrade the system There has not been enough time to consider bootloaders for the OOD A bootloader is essential for the lifespan of the product The product will not be attractive if users need special hardware to upgrade the firmware With an embedded OS the software upgrade process can be made trivial with Linux package managers As long as the web interface is used for only a small number of users
235. w the user to choose a close pool server for better accuracy and it saves the global NTP pools for unnecessary traffic 12 20 7 SNTP CLIENT 159 e The new function SNTPForceUpdate forces a new SNTP request Previously a new timestamp was only retrieved at given intervals e A new function void SNTPSetUpdateCallback void callback DWORD timestamp registers a callback which will be executed when a new timestamp is retreived This function is used to add a function in the date Time module to update the RTCC clock e Intead of having a fixed query interval the query interval can be modified and retrieved using set and get functions e The SNTP module can be enabled and disabled completely which is useful for debugging purposes if there is no network connection or if the owner wishes to do so for other reasons The changes are applied with the mal v2013 02 15 patch Inter microcontroller communication The two microcontrollers need to communicate with each other and they have a SPI connection between them for this purpose SPI allows for high transfer rates and full duplex communication and is normally used with one master and one or numerous slaves In the OOD the PIC24 will serve as the master and the PIC32 the slave which means that the PIC24 has to initiate all traffic The reason for choosing a client server model where the client initiates all traffic is because it fits well with the PIC32 s exi
236. which later will show to have a significant start up overhead in the order of seconds None of this will be a problem when using SSL only for authentication and not normal browsing Web server performance The usability of the web server has been tested but the performance must also be tested in order to see what the PIC32 and the HT TP server can deliver in terms of throughput and how it handles concurrent connections The TCP IP stack s raw TCP throughput performance is already documented in 14 but these numbers do not take into account the overhead of running the web server In chapter 15 2 the average read speed achieved with FatFS and the SD card using SPI was 618 kB s The throughput of the web server will never be higher than this but hopefully close The difference between the I O read speed and the web server throughput gives a rough idea of the overhead in the web server The tests will be performed on a 3 1 MB file the image called test jpg in appendix A The programs used for tests are wget siege and wireshark wget is used to measure throughput using one request user siege is a tool for stress testing HTTP servers which uses threads to perform concurrent requests repeated a number of times When it is done it prints a series of statistics wireshark a packet sniffing tool is used in SSL testing to time the delay from the client request is sent until the encrypted handshake has taken place Single connection throughp
237. wo main sections as illustrated in figure 23 2 the main page the public interface and the configuration page The various pages will be described in the following sections Main page The main page will mimic the appearance of the display with the name title portrait and current availability diplayed in a similar fashion Users may also if permitted by the owner access an interactive calendar to see the owner s upcoming appointments This calendar will be the same as the one in the private section of the web UI but without edit access The main page is unfortunately not yet implemented Configuration Calendar The calendar is a page consisting of an interactive calendar with month week and day views showing all the appointments New appointments are added by clicking on the desired day hour and if in day or week view the duration can be determined by dragging from start to finish time The best calendar 23 5 OUTLINE OF A PAGE WITH JQUERY MOBILE 177 plug in found is FullCalendarl a jQuery plug in which provides a powerful interactive and highly customisable calendar It comes with a Massachusetts Institute of Technology MIT license and is not intended to be a complete content management system and relies on the user to implement functionality for editing events by using hooks This is perfect since it does not include a lot of unnecessary functionality that is not needed The library support integration with Google Calen
238. y to contain a TCP IP stack graphics library and all other necessary libraries to provide the functionality needed 2 4 FINAL DESIGN 17 e Have enough RAM a concern mainly regarding Ethernet and TCP IP e Have peripherals suitable to interface to the remaining hardware e Have the computational power to perform RSA calculations and other cryptographic functions fast enough for hypertext transfer protocol secure HTTPS Time keeping The OOD needs to keep track of time so that it can change availabilitv information at appropriate times The accuracy is not critical but the main requirement is to have a means of svnchronising the clock Without a battery the clock will be reset whenever there is a power cut It cannot be relied on the owner to set the clock whenever this happens User interfaces The most important Ul of the two provided by the OOD is the web interface as it is the only means of remote controlling the OOD It is an absolute must that the interface works on mobile devices even on those with small screens If not the full functionality can be provided on devices that are challenging to support the minimum feature must be a way to change the current availability status There must be a way to easily authenticate the owner and allow no others access to the privileged pages If a password is required from the owner the password must be transferred from client to server fully encrypted No other information on the OOD is co

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