2008 [DAMN SMALL NAS]
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1. Chenxin Zhang sx07cz6 Kleves Lamaj sx07kI6 Monthadar Al Jaberi d04ma Praveen Mayakar sx07pm7 DAMN SMALL NAS Project work for Advanced Embedded Systems Course Lunds Tekniska Hogskola November 8 2008 DAMN SMALL NAS Abstract To build a small NAS with hardware resources enough to provide functionalities such as remotely accessible storage and a locally operated menu based administration application Extensive effort was put into building the functional subsystems of the Damn Small NAS viz PetaLinux installation and LCD controller Implementation oriented issues within the project time span prevented us from merging them successfully The main reason for not being able to complete the final product was due to the inconsistency between the Xilinx software and the PetaLinux distribution Advanced Embedded Systems Project a November 8 2008 DAMN SMALL NAS Table of Contents PCE OTA TINS AA A N E E A P A tard E A E A A E E E E 4 KEYWDS ore a a E A E T E E E A 4 E MO O E E E E E E 5 1 1 Project Description janiacrecarcusacdoncoussareseraccnnecencseatdeac dneceteeuwenenencsancamaaencauucetaeneaeadewenarsunaidonccoesnadsusaioe vues nensaned 6 1 2 The Project Roadmap mene see me Oe rr a Se ee ae eee ee 7 1 3 Deviations from the proposal ccccccccsssseeccccseseccecaueseccccseuecccecseeneccesseaueceessuusecessseaeaeeessagaeeeessagasees 8 Zi POICINUN co A AE TEEN AEE nat nentsaevanste poaieaamencate ont n2. Total Usage Number used as logic 259 J Numberusedas RAMs 68 J Number of Os 119 J Number ofbonded oBs O 232 0 5 Table 5 LCD Driver Device utilization summary Attached program ROM for the PicoBlaze is formed by a single block RAM and has a limited program size of 1024 instructions To simplify system architecture and Advanced Embedded Systems Project te November 8 2008 DAMN SMALL NAS configuration procedures no debugging facilities is included for the PicoBlaze and all the instructions are hard coded in the program ROM Although both microcontrollers are running at the same system speed but certain running procedures have to be followed when operating with the LCD module Therefore the PicoBlaze will take several clock cycles to complete an action requested from the MicroBlaze So to accomplish one complete data transmission the MicroBlaze has to issue command to start an action and the PicoBlaze has to acknowledge this back when action is finished This is known as the communication handshaking Bus interface registers are 32 bit each and they are in principle readable and writeable for both MicroBlaze and PicoBlaze In this application bus register O is utilized as a bidirectional interface for control signal transmissions between two microcontrollers where communication handshaking is performed register 1 is treated as a unidirectional register for data transmissions from the MicroBlaze to
3. PetaLinux A change in the symbolic link fixed the problem The change to be done is as mentioned below Ssudo rm bin sh Ssudo ln s bin bash bin sh The fix was to use Bash command interpreter instead of Dash which is a lightweight implementation of Bash 2 5 2 The other problems that was encountered during the compilation of PetaLinux was with the missing libraries a list of them is presented below e ncurses dev e zlib1g dev These libraries may have different name for other distributions 2 5 3 An effort to use PetaLinux on Virtex 2 was made to support enough usage required for the LCD and for other features intended along with Linux The Virtex2 had more resources in comparison to the Spartan 3E board However there was no support provided from the PetaLinux group for the Virtex2 board but for a similar family of board The investigation was done following PetaLinux manual with some changes necessary for the Virtex 2 board however there were issues in getting it done and it seemed to be a big task with no support being available Further work on trying to compile PetaLinux for Virtex 2 seemed rather not goal oriented and hence was stopped Advanced Embedded Systems Project ao November 8 2008 DAMN SMALL NAS 2 6 What could have been different If there was a second chance to do the project Xilkernel would have probably been chosen instead of PetaLinux This choice would not be because it is better but to meet the project tim
4. PicoBlaze 3 2 Controlling on LCD module Since a small microcontroller is chosen controlling the LCD module is straightforward Timing delays needed by the LCD module are generated in the software level and all the controlling sequences are coded in assembler Refer to the LCD datasheet See Reference 2 for more hardware requirements 3 3 Software interface Software interface provides the user few function calls that can be used in a standalone application to operate with the LCD controller In the current application project a text string is sent form the MicroBlaze to the LCD controller and entire data contents shown on the LCD module are left shifted every second Since PicoBlaze can only handle 8 bit input data at a time each 32 bit interface register is divided into 4 entries as shown in Figure 5 Lower 8 bit data in both registers are used in the MicroBlaze to send data to PicoBlaze Upper 8 bit data in register O is used by the PicoBlaze for sending acknowledgement signal back to the main application The rest of register entries are reserved for further developments Control commands sent from the MicroBlaze through register O lower 8 bit are listed in Table 6 Advanced Embedded Systems Project aa November 8 2008 DAMN SMALL NAS Each data communication in the main application acts as a block read or write It is initialized by putting data in the register 1 and then sending data command through register 0 The main appli
5. by creating the user accounts prior to the cross compilation of PetaLinux 7 3 The Xilinx File System Xilinx has included with the EDK a file system called Xilinx Memory File System MEFS This file system can be utilized on the standalone project mode or even together with the Xilinx s kernel called XilkKernel The system resides in RAM ROM Flash memory and can be accessed directly The following are a list of functions built in the XiIMFS void Mie init Te ink numbytes char addrege int init type void mfs init genimage int numbytes char address int init type int mfs create dir char newdir int tits delete dirichear dirnane int mfs get current dir name char dirname int Wile renane Tile dhear iron tile cher te tile int mis exists Tile char filename int mfs dir open char dirname ine Wis dir close ine td ine Wie Lile open char lilenanme int mode inc Wie Tile writelint ta Ghar but ano burlen Advanced Embedded Systems Project an November 8 2008 DAMN SMALL NAS int ts Tile closeiin Ta int mis ls void int mfs cat char filename int mis copy stdin to tile char rilename int Mie Tile copy cbar tron tile char fo Tile To illustrate the usage of these functions a shell like application was written which would run on a system built with EDK The following hardware setup was chosen as shown in Figure 7 below L M M B E E Name Bus Connection IF Type IF Version E lt gt
6. microblaze_0_bootloop i Ael Default microblaze_0_xmdstub H W Project TestApp Memory E Processor microblaze_0 oo Executable C DEPOT 099_VHDL EDK RAMNET shell executable elf E Compiler Options Gl Sources be CADEPOT0S9_VHDLEDKRAMNE T shellsrc owntunctions c CADEPOTIS9_VHDL EDKRAMNETshellsrc shell c E Headers i Shell src ownfunctions h Figure 8 Software Layout The code has been divided into two source files and a header file is included to keep the functions declarations and other major constants and defines Since the shell was never intended to be used as a fully fledged shell i e being able to load execute other files due to lack of operating system it is rather a simple program that wraps the file system functions provided by Xilinx In Figure 9 and Figure 10 the settings for the platform generator are shown It is necessary to enable the xilmfs library on the library generator to be able to use the functions included on the xilmfs library Furthermore as shown on Figure 10 the settings for the new file system would have to be indicated to the library generator CPU Dever cou CPU Deter Version 1 11 Precesace Darneneters ae Curent Value Det sual Wish Type Demonte mebla _ wndatub perished debug mwin Tel nena merge reemer Dehi penpals he Lamed wih eetahi mim compie isa g J saing Bim compder flags used in BZP and leroy perami chee mi mna arg Aachia ueed be achia races for both ESF
7. or a VGA to give feedback to the user Will it use a UART or keyboard to be accessed through In early week 2 it was basically decided to use an LCD RAM as storage and UART Now investigation for appropriate software architecture began with three main solutions e All custom solution e xXilKernel as the base OS kernel with xilMFS e Linnux as a complete operating system with accompanied applications Human resources were split on the two latter options because the first was not viable for such a short project uCLinux was investigated A shell like file system was written to test how easy it was to use the provided Xil MFS from Xilinx And Xilkernel was up and running with an Echo TFTP HTTP servers During week 3 PetaLinux implementation of uClinux was chosen to be used as the Linux solution While Xilkernel was tested to run with pthreads semaphores and message passing between threads The fourth week was the week that the Linux solution was chosen to be fully implemented Cross compilation of PetaLinux was a problem Also during this week flash memory was successfully used to store bit stream and code instead of being downloaded again every time the board was turned off and on again In week 5 there were problems with synthesizing the reference design for the PetaLinux The cross compilation problems were still persistent At the same time there was an investigation of the PS2 controller that would be later on integrated into the referenc
8. 3 Relying on external tools create a lot of dependencies and lack of support could lead to delay Advanced Embedded Systems Project 200 November 8 2008 DAMN SMALL NAS 5 Contributions LCD Standalone project design PetaLinux analysis Compiling PetaLinux LCD Linux driver attempt Sections 2 1 3 1 3 2 amp 3 3 Chenxin Zhang Project proposal presentation File system analysis Kleves Lamaj File system shell programming Investigation for Linux file system Investigation for PS2 Controller Chapter 7 Xilkernel Analysis Compiling PetaLinux LCD Linux driver attempt Final project presentation Sections 1 2 2 2 2 3 2 4 amp 2 5 Monthadar Al Jaberi Investigation for PS2 Controller Praveen Mayakar PetaLinux investigation for Virtex 2 Sections Abstract 1 1 1 3 2 6 Chapter 4 Appendix C amp Chapter 9 Advanced Embedded Systems Project Ca November 8 2008 DAMN SMALL NAS 6 Appendix A Xilkernel Xilinx provides a small kernel called Xilkernel that is packed with many features The major features are e Multithreaded e Posix compliant e File system for RAM ROM devices e TCP IP stack called IwIP These features made Xilkernel an interesting candidate to be the base software platform for the product Despite of being successfully able to run not just a TFTP but also an echo and web server it wasn t chosen to be used in the product Message passing and mutex handling was also running successfully The r
9. a moevbhaze_0 microblaze 710d s inh Imb_v10 1 00 4 a nb Imb_v10 1 00 a E e ee pib_v46 1 03 a H aea Imb_bram_if_cntlr 2 10 a O E in oir Imb_bram_if_cntlr 2 10 a I DDR SDRAM mpme 4 03 a lt ib bamn bram_block 1 00 a E debug modue mdm 1 00 d H WF e e proc_sys_reset 2 00 2 H D hemet MAC xps_ethemetlite 2 00 b H Fs ABT xps_gpio 1 00 3 E T Fushfuttons_ SBT xps _gpic 1 00 3 E Pops ine d xps_intc 1 00 3 Gans imer T xps_timer 1 00 2 R A5232 Uar xps_uartlite 1 002 obek generator 0 clock_generator 2 01 a Figure 7 Hardware Layout Some of the IP cores on this system are redundant such as Ethernet_MAC LEDs _ 4Bit PushButtons etc they were left there in case this system would have been the chosen architecture for the NAS project The only IP Cores that are relevant to this test setup are the UART the Microblaze and the Debug Module MDM On the software side a C program was written which would read an entire line of text from the UART tokenize it and store it into an array of strings and send it to another function which would match it against some predefined commands i e Is mkdir clear etc and execute the command by using the appropriate XiIMFS function s The layout of the software is shown on Figure 8 below Advanced Embedded Systems Project ao November 8 2008 DAMN SMALL NAS Software Projects EEJAdd Software Application Project be eal Default
10. acenane IE E A N E 9 2 1 PS AUN e A E A E E E E E 9 2 2 User manual and Instructions cccccessseeeeeeeceeccececeeeeaaaeessssseeeseeeeeeeeeeeeeeeeeaaaeeeueeseeseeeeeeeeeeeeeeeeenaaas 10 2 3 LCD Linux driver ECON Cis sarcastic eacceseadscrsteesavasevoristeainenctiodsnctaneatevennssue sbeannemssnasuneibousacd ionsiasathonsaeadscutouxacnnneos 11 2 4 Problems with generating Own hardware design ccccsssccccccssseccccceeeccecsseneecesseuaeseeeessueecessaansess 12 2 5 Problems in compilation of PetaLinUx cccccsscccccssesssecceceessecceceueeeccesauaaeceessuaseceessuaueeesssenseseessaees 13 2 6 What could have been different oeseensneeneseeerressssssssssrsrrerrreressresssssssssessreeerreeeesssssssssssessseeeereene 14 3 LCD interface standalone project sisccsccinscsrccdanscssacacesatensassomnconecbecaedsosasecnsaccnevnnsenedhenuemensincaansnooadguasacbedounmencasiecaness 15 3 1 Hardware architecture sss ccasssncasmackctesgquetesaatodacaussodsecantetedceatmncnantoleadsadoxceaalteisacsaddcesweluadsadseebesetadmesn caceusedens 15 3 2 Controlling on LCD module ooennnooseennssseeeenssseeersssreresssrrrosssrerossssrerossereesssreresssreressssreresssreressererssseerene 17 3 3 SOU AS Interface sceindis 17 A Lessons LEa ea puasinac es sete uvocie ain saasmeulendn sy ensaaae Ness pans erie nete ena er sadam nia bans puenienesenhenniod 20 5 CORNET TIDE NIN os ee sere pete nesicacte E E EE E 21 6 A
11. added to the Makefile so that the driver would be visible in the kernel configuration menu obj CONFIG_INPUT_PICO_LCD picolcd o The driver was stripped down to only setting up what is necessary excluding interrupt handling to make the device visible to applications running inside PetaLinux Basically that is allocating memory within the system and doing a mapping from the address of the device to where the newly created resource is then giving the driver a name in this case PicoLCD Whenever an application tries to access the device it will search for the driver s name A copy of the modified Makefile and the driver is attached with the project After adding the driver one would need to include it in the cross compilation of PetaLinux and that is done while customizing the kernel Linux Kernel Configuration gt Device Drivers gt Input device support then enabling the driver in this case called PicoLCD But due to failure of adding custom hardware to the reference design the driver was never tested 2 4 Problems with generating own hardware design 2 4 1 The only successful synthesis of the hardware was while synthesizing the reference design without any changes Also another major issue was that the synthesis was only successful with Xilinx EDK version 10 1 without any service packs installed otherwise the FS Boot which is the first stage boot loader fails to boot U Boot the second stage boot loader All attempt to synt
12. an board and make it work for the interrupt mode An idea to integrate the core with the Linux and use Linux s interrupt scheme for the controller was conceived However since there were no known methods to integrate the cores with the PetaLinux and time was spent on investigating methods to make the integration work the interrupt mode could not be attempted Advanced Embedded Systems Project e November 8 2008 DAMN SMALL NAS 9 References 9 1 Reference 1 PicoBlaze Manual htto www xilinx com products ipcenter picoblaze S3 V2 Pro htm 9 2 Reference 2 Spartan user guide Xilinx UG230 Spartan 3E Starter Kit Board User Guide http www xilinx com products boards s3estarter reference designs htm 9 3 Reference 3 Compiling amp Configuring PetaLinux http developer petalogix com wiki UserGuide Basics 9 4 Reference 4 Downloading PetaLinux http developer petalogix com wiki BoardGuides Xilinx S3E500 Tutorial Note that this tutorial is for revision C of the Spartan board It would require minor changes to be done while following the tutorial 9 5 Reference 5 Keypaddev c available in the download package from PetaLinux S PETALINUX software linux 2 6 x petalogix drivers input keypaddev c Picolcd c is available in the archive Icd drivers files submitted Advanced Embedded Systems Project Eo
13. cation will then be blocked until reading an acknowledgement signal back Inside the LCD controller the PicoBlaze runs in an idle stage after initializing the LCD module where it listens on its input port and records input data in both command register and temporary data register A known data command as listed in Table 6 will trigger the PicoBlaze to jump into the corresponding sub routines to execute a certain task At the same time a recognized data command will also trigger the PicoBlaze to send an acknowledgement signal back to the MicroBlaze through register 0 Additional logics on the OPB bus will clear the lower 8 bit data in register O when PicoBlaze responses which prevents command re executing in the PicoBlaze The software flow chart is shown in Figure 6 RegO O 7 8 15 16 23 24 31 Command passed Acknowledgement to PicoBlaze from PicoBlaze Reg1 O 7 8 15 16 23 24 31 Data to PicoBlaze Reserved Figure 5 Software interface register entries Sending data to the LCD controller 0x01 Write data and display data content on the LCD module l Clear data contents on the LCD 0x03 Clear display module Set cursor position on the LCD Set cursor position module for next character writing Shift entire data contents displayed Shift display left on the LCD module to left by 1 position Advanced Embedded Systems Project November 8 2008 DAMN SMALL NAS Call for 1m sec
14. cores were forced to be updated On the software side all the desired functionalities are bundled with the OS platform such as the file system FTP server HTTP server etc Figure 2 Hardware units used in Reference design Referring to the building blocks shown in system architecture as shown in Figure 1 two system peripheral devices are missing in the PetaLinux reference design They are the LCD controller and the PS2 core Advanced Embedded Systems Project November 8 2008 DAMN SMALL NAS Therefore two additional hardware blocks have to be added into the hardware project and their corresponding device drivers in Linux have to be developed 2 2 User manual and Instructions The board connections are as shown in Figure 3 The connections require one RJ45 for Ethernet connection and one RS232 for the feedback from PetaLinux oe ee Eune jed e es i E k th SPARTAN 3 a uf i Fa e 2 gri E gm Bo j k ae Ff g j E d a ri ot Figure 3 Connections to Spartan target board When PetaLinux has booted up and the prompt is available the user should type in the account name and password which is as Username root Password root The installation compilation and configuration instructions for the PetaLinux on the Spartan board can be found on PetaLinux webpage See Reference 3 amp Reference 4 Now for the user to be able to communicate and transfer f
15. e design Also an LCD custom hardware was being developed separately on a standalone system minimizing the potential problems that would occur if it would have been integrated into the Linux directly An investigation on installing PetaLinux for Virtex 2 was also made with ambiguity towards enough space on the board with all the planned features and extra ones that were planned to be used once Linux was up and running In week 6 the PetaLinux cross compilation was solved LCD was suffering from software synchronization An attempt of writing a Linux driver for the LCD controller was done Advanced Embedded Systems Project cae November 8 2008 DAMN SMALL NAS In the final week the LCD standalone solution was working successfully PetaLinux was only working with the reference hardware design without any modifications so PS2 was abandoned The LCD controller was treated as a separate project therefore the LCD controller Linux driver was not possible to be tested So in the end this project ended up with two projects the PetaLinux design and the LCD standalone project 1 3 Deviations from the proposal The use of the LCD display was made for a menu based program to be able to administer commands to see free space on the storage media or to format the media The proposal was however not implemented due to the lack of a good Linux reference system to test the implementations done with LCD however the final product has the stand alone LCD contro
16. e random access memory BRAM Block Random Access Memory VGA Video Graphics Array UART Universal asynchronous receiver transmitter OPB On Chip Peripheral Bus PLB Peripheral Logic Bus XPS Xilinx Platform Studio GPIO General Purpose Input Output IP Core Intellectual property Core EDK Embedded Development Kit DHCP Dynamic Host Configuration Protocol OS Operating System TCP IP Transmission Control Protocol TCP and Internet Protocol IP TFTP Trivial File Transfer Protocol Xil MFS Xilinx Memory File System LED Light emitting Diode MDM Microblaze and the Debug Module RS232 IBM Recommended Standard for serial cables Keywords PetaLinux Linux distribution from PetaLogix XilKernel Kernel from Xilinx PicoBlaze Processor core from Xilinx for FPGA amp CPLD MicroBlaze Processor core from Xilinx for FPGA Spartan FPGA family from Xilinx Virtex FPGA family from Xilinx FS Boot File System Boot Loader U Boot Universal boot Loader POSIX Portable Operating System Interface for Unix systems Mutex Mutual exclusion algorithms used in concurrent programming Advanced Embedded Systems Project a November 8 2008 DAMN SMALL NAS 1 Introduction Network attached storage NAS is a file level computer data storage system connected to a computer network providing data access to heterogeneous network clients The product has the following functionalities e Network connectivity e Acc
17. e requirements All problems with compilation and synthesis would not have emerged That would have been a major advantage in looking for optimization and enhanced features for the product On the other hand using Xilkernel is not a long term solution because it is really hard to expand the product with new features Everything needs to be written by hand for example if DHCP would be a requirement for the product then a DHCP program along with some low level implementation would have to be done Thus it would be a major hindrance in project time constraints Choosing Linux as the operating system one would have higher complexity in the initial phase to compile configuring the system booting and running custom applications This would facilitate ease of adding newer features and hence would be faster implementations One could also add variety of applications from open source which are developed by the Linux community On the contrary using Xilkernel would be less complex and be a faster implementation initial phase However it would have a higher complexity and hence time taking as the need to add more features are required The key factor to choose the OS should be based on project s timeline requirements Advanced Embedded Systems Project wo November 8 2008 DAMN SMALL NAS 3 LCD interface standalone project A customized LCD IP core was designed to drive the LCD module available on the Xilinx Spartan 3E starter kit The core p
18. eason to abandon it in favor for a Linux kernel was for the vast access to already running and tested open source application that was not just shipped with Linux but is also available to be downloaded from the web and then cross compiled to run inside Linux Advanced Embedded Systems Project aan November 8 2008 DAMN SMALL NAS 7 Appendix B File System 7 1 Introduction Any NAS Network Attached Storage would be in need of a file system where the user s data would be stored and retrieved from with ease When the project was started a common decision was taken to investigate at least two file systems and then later on commit to one of them This was done to be able to parallelize work among group members Our choices in this matter were Xilinx own file system XiIMFS and Linux file system This appendix will cover the former of the two 7 2 The PetaLinux File System A quick glance at this file system reveals that it is capable of all the standard operations upon files and folders i e creating moving copying and deleting them All of these while maintaining an active pointer to the active working directory which can be retrieved through PWD present working directory This allows for successful storage and retrieval operations on data which would be catered to the user of the NAS through the FTP server So far it is lacking the ability to add remove users at runtime like most standard PC Linux s would This can be remedied
19. essibility to storage medium e FTP e LCD display can be used for menu based operations The user interacts with the product using a PC to connect to the FTP server to download and upload files The Xilinx Spartan board was used with a built in LCD considering enough support for memory and CPU requirements The necessity to have an operating system to support low level implementations and for using a pre implemented FTP was realized during the implementation of the product Linux seemed to be an ideal choice as it comes with enough hardware and driver support and is small in size to fit the board requirements The enhancement on newer feature to add new drivers supported from within Linux made Linux a much preferred choice This document describes in detail the implementation of such a product An overview of each of the sub system modules is described with details on both the hardware and the software The problems faced and necessary deviations done to realize things within the limited time have been mentioned as well A user manual for one willing to try the product is available and a brief note on lessons learnt and future improvements are also part of this document The appendices describe all the efforts and investigations towards getting the planned features implemented Some of the investigations could not be used in the project with available time to implement and hence could only be stated as some useful learning Hence some of these car
20. garara aoe word ai hor apypde atieeree compler mao mbes aan Cimpia weed lo campie both GSP ibemies aed Appbcstions OS i iray reiii OS mandsione e Veson 200a Uia library a wia whet a Le Miro In ayatem and Sertal Flash Library milan IF Fir Faih ray for al AMD CF camgar piiraa fash wis ai y Pea pene ae Pee 25 ess tea sree an A FATTE wp 00a bw TCP IP Stace Ibray 2 00 8 bong 130 a Ur bel TEPIP Stack Mbeary bel v1 3 0 Xiro adapter v 1 00a Figure 9 Platform Settings Library settings for enabling xilmfs Advanced Embedded Systems Project 25 November 8 2008 DAMN SMALL NAS Enable S W Wtrusive Profiling on Hardware Targets Custert Value Delat Value true faise MFSINIT NEW MFSINIT_NEW Qe SOGCO0GS 10000 100000 Figure 10 Platform Settings Details of the xilmfs library Advanced Embedded Systems Project 26 November 8 2008 DAMN SMALL NAS 8 Appendix C PS2 Controller The PS2 controller used in the product was an IP core from Xilinx called XPS PS2 The core is a PLB bus slave designed to control PS2 protocol keyboard and mouse It uses simple state machine and works on shift registers Each of the PS2 ports is controlled by a 4 byte wide registers For transmitting data a byte is written to the transmit register and then the data is serialized and transmitted to the PS2 device Transmit status registers and interrupts indicate whether the transmission is complete and if there are any err
21. hesize on the universities computers or different laptops with different service packs install failed 2 4 2 A major blow to the project was the inability to add custom hardware design into the reference design The same problem mentioned above was observed even when adding the smallest unused custom hardware design The Xilinx EDK version problem mentioned earlier could also have been a cause for this Another fact that confirms our suspicion about version problem is that Xilinx EDK version 9 2i succeeded in compiling and running the whole Linux operating system while just adding an extra OPB core but that was discovered after the project ended Advanced Embedded Systems Project Ea November 8 2008 DAMN SMALL NAS Based on the observations made the reasons for the problems encountered are presumed to be one of these e Synthesizer Place amp Route e P Core changes With limited support and available time we could not proceed to fix this issue and hence the pre built hardware design was used 2 5 Problems in compilation of PetaLinux 2 5 1 One of the major issues that stood in the way of compiling PetaLinux was that the host operating system that contained the chain tool for cross compilation wasn t configured and hence had to be re configured The host machine was running Ubuntu distribution a Linux distribution based on Debian another Linux distribution that used a different command interpreter than what was expected by
22. iles to the target board there would be some network settings to be done The host machine settings and target machine settings are as mentioned in Table 1 and Table 2 below Advanced Embedded Systems Project o i 8 2008 DAMN SMALL NAS 192 168 0 X where X is not equal to 10 755 255 255 0 Table 1 Host machine network settings Once the above settings have been done the user can open a FTP client and connect to the server Table 2 Target machine settings For the user to receive feedback from PetaLinux the RS232 cable will be used along with a terminal program that must have the settings as in Table 3 below Flow control Hardware Table 3 Terminal program settings The only read write directory in the target machine is tmp and hence the user can upload data only to tmp 2 3 LCD Linux driver attempt After completion of the LCD standalone module the second step would be to write a Linux driver After some searching in the file structure of PetaLinux a similar driver was found that was controlling the rotary button See Reference 5 Keypaddev c was an example driver provided with the reference design which takes care of communicating with a rotary button that is supplied with the Spartan 3E board Advanced Embedded Systems Project oan November 8 2008 DAMN SMALL NAS A new driver was created called picolcd c See Reference 5 based on the keypaddev c driver And a new entry was
23. ller that can text data to the LCD display The text can also move as a marquee The PS2 controller was used from the Xilinx IP core library however since the menu based program could not be made its use could not be materialized Advanced Embedded Systems Project ao November 8 2008 DAMN SMALL NAS 2 PetaLinux 2 1 PetaLinux PetaLinux is source based hardware and software distribution which has been developed specifically for using Embedded Linux on reconfigurable logic devices The PetaLinux distribution includes everything needed to easily create Linux systems running on Xilinx FPGAs The entire PetaLinux development package is freely downloadable from the PetaLogix homepage see Reference 4 which includes the hardware reference projects designed for varieties of Xilinx FPGA development kits uClinux kernel configuration utility with few Xilinx devices included and some additional software tools such as the C cross compiler hardware design creation tool etc Due to the availability of suitable development packages from the PetaLogix and their promising demonstration reference designs the PetaLinux was chosen in this project without more relevant searching on other OS platforms Included hardware units in the reference design are shown in Figure 2 where the project was created in Xilinx EDK version 9 1 To generate system image file the entire project files were loaded in and updated to Xilinx EDK version 10 1 where some of the IP
24. ond delay achieved 0x07 Delay 1mS in the LCD controller written in assembler Call for 20m second delay achieved 0x08 Delay 20mS in the LCD controller written in assembler Call for 1 second delay achieved in 0x09 Delay 1S the LCD controller written in assembler Table 6 Command list of LCD IP core The software flow chart is shown in Figure 6 below Waiting ack signal from LCD controller to initialize the LCD module LCD initialization Data sending via REG1 Function call Writing text string on LCD Command sending via REGO Acknowledge to host Forever loop Waiting for acknowledgement Record input in command register Function call Delay 1s Function call Display left shift a Received b i Record input in data register Known command Execute command c Figure 6 Software flow charts a Program flow in a standalone project b Program flow in a function call c Program flow in the LCD controller Advanced Embedded Systems Project ae November 8 2008 DAMN SMALL NAS 4 Lessons Learnt 1 Itis hard to estimate a complex project without knowledge or experience of tools which have dependencies 2 One must be careful in parallelizing the tasks in a project with a shorter deadline
25. ors reported The received data is written into the receive register Similar to the transmit status registers receive status registers and interrupts indicate whether data has been received from the PS2 device The XPS PS2 Controller generates interrupts upon various transmit and receive conditions Initially the Virtex 2 board was used as it was a hardware resource available with the team working on the PS2 controller Later the same methodology was used for the Spartan board The below sequence of steps were followed while the core was used for our reference design e Verify standalone usability in a polled mode o Platform Virtex 2 Board o Hardware PS2 XPS core Microblaze XPS Bus controller o Software Standalone in polled mode e Verify standalone usability in a polled mode o Platform Virtex 2 Board o Hardware PS2 XPS core Microblaze XPS Bus controller OPB to PLB Bridge OPB bus controller o Software _ Standalone in polled mode The inclusion of the bridge was necessary for the PS2 controller operating on the PLB bus to communicate with the main OPB bus in PetaLinux e Verify standalone usability in a polled mode o Platform Spartan 3E Board o Hardware PS2 XPS core Microblaze XPS Bus controller OPB to PLB Bridge OPB bus controller o Software Standalone in polled mode Advanced Embedded Systems Project 27 November 8 2008 DAMN SMALL NAS The next step was to run the controller for the Spart
26. ppendix I cccsresis sues catercrciost sree once enenanece vatecneacsauusesceusnusoassansatanceacaunonceseeearssesecusetacceeviwaecarcsteraertacaatae 22 7 Appendix B File SVSCCM so ssissccescscacccsussaiessaccesstaencsessansacedescs ensedevararenceustassadedotasorsaddeanetansavsancandeiansersudvananteswacdons 23 7 1 Tahidele m n o a E E E E E E E E E E E E er E eet 23 7 2 The PetaLinux File SSE INN secs tccset seis ect esees esas pace ara aecineade oe ahaa cae caie as mca aatonteadteanaeneeeannaeet 23 7 3 The Xilinx File System yoscsesecaverdsxceencnoracinrscassesncesmedarc eeceoteswandanesevineseod awanagsaaeeuneddousdeavcamed madeansaeecdaveenteoss 23 8 Appendix C PS2 Controller ivwvesescesiccseseesesencadssnaevoowesadeorseceusenwaeedsnvondoeniesadeneeyseusbawwedussnedeavoanduneussausepvasedncausausviaseas 27 RDS INC e a E E E E E deaecedeacaecenunterceencee 29 9 1 FT Leepa EE EE E E EE 29 9 2 RETEG Da E E E E asceee eee anes nee 29 9 3 PRETO RCI CS Soe E E A A 29 9 4 Referente Aoro a T O Seadesuntaiastacetantsicstianes 29 9 5 PRTC NCS D e E E E E 29 Advanced Embedded Systems Project aooo November 8 2008 DAMN SMALL NAS Acronyms NAS Network Attached Storage FTP File Transfer Protocol LCD Liquid Crystal Display CPU Central Processing Unit PS2 Personal System 2 IBM Standard Controller for keyboard and Mouse FPGA Field programmable gate arrays RAM Random Access memory ROM Read only memory DDR RAM double data rat
27. ried out during the implementation of the project were not included in the final product In the end the product was two subsystems which could not be merged the PetaLinux installation and the LCD controller Advanced Embedded Systems Project oan November 8 2008 DAMN SMALL NAS 1 1 Project Description The project intended towards making a small working product of a NAS was carried on with an investigation on making use of available hardware resources The target board is a Xilinx Spartan 3E Starter board with the following specifications 500K Gates 64 MB DDR RAM 16 MB ROM Ethernet Port 2x Serial Ports LCD screen PS 2 Port VGA Port General I O ports The hardware architecture used in building the NAS is as shown in Figure 1 below Figure 1 Hardware architecture for damn small NAS The damn small NAS as a product with the two sub systems PetaLinux installation and the LCD controller which uses both hardware and software parts whose functionalities are mentioned in the coming chapters The hardware used was a Xilinx Sparta3E500 board which included an LCD display The software work was mostly confined to Linux its compilation Advanced Embedded Systems Project aa November 8 2008 DAMN SMALL NAS 1 2 The Project Roadmap Everything started with a brainstorm during week 1 and a NAS product was decided with very few technical details Will it use RAM as storage Compact flash SATA drive Will it contain an LCD
28. rovides an interface to the host side MicroBlaze to control or communicate with the LCD module From a user standpoint a simple software interface is highly desirable Running speed of the available LCD module is slow comparing with the main system since all the timing and delay requirements for the LCD module are given in milliseconds where the main system runs at nanoseconds To issue commands into the LCD module a certain running procedure needs to be followed with well controlled timing requirements as specified in datasheet To control the LCD module the needs could be seen as a well controlled state machine behaving at a lower action speed than the main application A small microcontroller was chosen in this case to achieve requirements not only due to the conveniences but also the smaller hardware occupation 3 1 Hardware architecture The customized LCD IP core is created on an OPB bus where communications with the main application are realized through two bus registers as shown in Figure 4 The LCD IP core is mainly composed of a PicoBlaze with a program ROM attached Because the PicoBlaze has only one input port and one output port that each port has 8 bit data a multiplexer for driving multi input output port signals is used to interface with different bus registers Due to the hardware connections available on the board the LCD module is used in 4 bit data transmission mode So a 4 bit data bus and three additional control signal
29. s enable register select read write are connected to the port multiplexer of the PicoBlaze A list of the assigned port IDs for different input output port selections is as shown in Figure 4 below OPB Bus Wrapper PicoBlaze LCD E ma Module REGO A REG1 ROM Figure 4 Simplified LCD IP core block diagram Advanced Embedded Systems Project ae November 8 2008 DAMN SMALL NAS LCD data bus and control signals Table 4 Port address of input output multiplexer PicoBlaze is a simple 8 bit microcontroller primarily for the Spartan 3 devices which is mainly used in applications requiring a complex but non time critical state machine See Reference 1 The main reason of choosing the PicoBlaze to drive LCD module is due to the smaller hardware size As stated in datasheet complete processor requires only 96 slices in Spartan 3 FPGA devices When considering the needs in driving LCD module if a finite state machine was used one could guess a similar or even larger hardware usage would be required In addition choosing to use a microcontroller in this case also simplifies system design flow and leaves rooms for updating system functionalities without requiring more hardware resources The PicoBlaze used in this application is driven by the OPB bus clock and bus reset signal The device utilization for LCD controller is as in Table 5 below Device 3s500efg320 4 Used
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