1. INTRODUCTION 1.1 PROBLEM DEFINITION The basic
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1. R26 R US_0207 10 0207 10 RESISTOR American symbol R27 R US_0207 10 0207 10 RESISTOR American symbol R28 R US_0207 10 0207 10 RESISTOR American symbol R29 R TRIMM6 4W RTRIM64W Trimm resistor R30 R US_0207 10 0207 10 RESISTOR American symbol R31 R TRIMM6 4W RTRIM64W Trimm resistor R32 R US_0207 10 0207 10 RESISTOR American symbol R33 R US_0207 10 0207 10 RESISTOR American symbol R34 R US_0207 10 0207 10 RESISTOR American symbol R35 R TRIMM6 4W RTRIM64W Trimm resistor R36 R US_0207 10 0207 10 RESISTOR American symbol SV2 S10P S10P AMP MT CONNECTOR SV3 SO5P S05P AMP MT CONNECTOR SVA S12P S12P AMP MT CONNECTOR SV5 S08P S08P AMP MT CONNECTOR SV6 S04P SO4P AMP MT CONNECTOR Micro controller board Part Value Device Package Description C1 CAPNP 5 G5 C2 CAPNP 5 C 5 c3 ELC 2 5 ES 2 5 C4 ELC 2 5 ES 2 5 C5 ELC 2 5 ES 2 5 C6 ELC 2 5 ES 2 5 C7 CAP 5 C3 c8 ELC 2 5 ES 2 5 C9 CAP 5 Go CON2 CON40 CON40 CONNECTOR D1 1N4004 1N4004 DO41 10 DIODE D2 1N4004 1N4004 DO41 10 DIODE D3 1N4004 1N4004 DO41 10 DIODE D4 1N4004 1N4004 DO41 10 DIODE D5 1N4004 1N4004 DO41 10 DIODE D6 ZENER DIODEDO41Z210 DO41Z210 Z Diode D7 DIODE 2 5 D 2 5 IC1 AT90S8535P AT90S8535P DIL40 MICROCONTROLLER IC2 DIL16 DIL16 Dual In Line ECS DIL16 DIL16 Dual In Line Q1 XTAL S QS CRYSTAL R2 R US 0204 5 0204 5 RESISTOR American symbol2. 1 7 REQUIREMENTS 1 7 1 Hardware Atmel AVR 9088535 Micro controller Max 232 RS 232 level shifter GSM Modem Nokia 7110 Siemens MC35 Dial up modem Copyright 2004 Defense Research amp Development Organization DRDO India Embedded Network Client amp Data Acquisition System 1 7 2 Software Codevision C Cross Compiler for AVR Micro controllers sP12 chip programming utility AVR ASM3z2 assembler for AVR Micro controller AVR Studio simulator for AVR Micro controller GNU GCC Copyright 2004 Defense Research amp Development Organization DRDO India Embedded Network Client amp Data Acquisition System 2 DESIGN ISSUE 2 1 REQUIREMENT ANALYSIS The basic requirement of DRDO was to make available the sensor data on the desktop This could have been achieved in many ways But to make the implementation more robust and non proprietary we decided to go by standards and implement the whole UDP IP stack on the data source end 2 2 UML DIAGRAMS E MESE E AT9058535 Ne amp PortA int T T A r r amp PortB int Hh e a a ME amp bPortC int E d ourcePort int H T amp PortD int of stPort int P SIT NEES o LS T L L har H Rz DM Sconnect ta c Z Le m 2 Ssend2Driverf length int mt YQ SreceieveFromDriver amp ychksun See 1 1 e RydataReg int N t SaddHeade s lad H IP T Vua sia SO identification int
3. 40 Embedded Network Client amp Data Acquisition System 3 3 IMPLEMENTATION ASPECTS The initial aim of the project was to build an embedded data acquisition system that would terminate on LAN using Ethernet LAN controller CS 8900A The major problems faced using the CS 8900A were that the chip is not readily available and is expensive Though this being our primary goal the system our client DRDO needed was just a mechanism for remote data retrieval and monitoring So to meet the basic requirements we went on to implement the system using dial up modem and the EPBAX system that currently exists in the client s premises Another challenge put forward by our client is to make the system generic enough so as to interface with any sensor The answer to this has been explained in the hardware design Another trivial looking major modification was to make calibration of the sensor data flexible and changeable by the user as and when attached sensors changes This is achieved by providing an extensive user interface Dial up connection imposes its own drawbacks like one line has to be dedicated and the line has to be up or has to be up whenever required These conditions may not be met every time and hence some other means had to be there to access the data during emergency To address these issues a major revamping of the project was done and GSM module implementation interfacing and its driver along with the specific protoco
4. Embedded Network Client amp Data Acquisition System 3 PROJECT DESIGN 3 1 HARDWARE DESIGN Hardware has ample share in the project Hardware design the most time consuming phase in the project consists of sensor interfacing GSM interfacing and modem interfacing 3 1 1 Block Diagram of the overall hardware system Power Supply Unit GH 12V 6V 5V 33V LCD amp Interface GSM Modem Signal Conditioning 4 20m4 to 0 5V i Keypad amp Interface Microcontroller Unit Relay Interface amp Control Level Converter KER Internal 10 bit ADC I Multiplexer UART Dial Up Modem L In System Programmer Remote Terminal Unii RTU Field Mobile Phones PSTN EPBAX LAN ISP Remote Users Copyright 2004 Defense Research amp Development Organization DRDO India 9 Embedded Network Client amp Data Acquisition System Power Supply Unit The power supply unit consists of step down transformers bridge rectifier and filter and regulators that convert the voltage from the mains into the 12V 6V 5V and 3 3V Signal Conditioning The circuit provides the interface for up to four sensors having the standard 4 20mA outputs This signal from the sensor is converted to 0 5V for ADC by using Op Amp signal conditioning The calibration is done by span and zero adjustment Relay Interface amp Control The output control bus from the micro controlle
5. R3 R US 0207 10 0207 10 RESISTOR American symbol R4 R TRIMM6 4W RTRIM64W Trimm resistor SV1 S05P S05P AMP MT CONNECTOR SV2 S10P S10P AMP MT CONNECTOR SV3 SO5P SO5P AMP MT CONNECTOR SV4 S16P S16P AMP MT CONNECTOR SV5 S08P S08P AMP MT CONNECTOR SV6 S02P S02P AMP MT CONNECTOR SV7 S06P S06P AMP MT CONNECTOR T1 2N706 2N706 TO18 NPN TRANSISTOR US2 CHIPCARD ISO 7816 CHIPCARD ISO 7816 ISO7816 Chip card connector ISO 7816 X1 20FLZ SM1 20FLZ SM1 20FLZ SM CONNECTOR X2 20FLZ SM1 20FLZ SM1 20FLZ SM CONNECTOR Copyright 2004 Defense Research amp Development Organization DRDO India Embedded Network Client amp Data Acquisition System X3 FO9H FO9H SUB D X5 F09H F09H SUB D Copyright 2004 Defense Research amp Development Organization DRDO India 17 Embedded Network Client amp Data Acquisition System 3 2 SOFTWARE DESIGN Software design has been divided into two parts namely Micro controller programming and Graphical User Interface GUI programming Micro controller programming is a major part of the project where all the networking protocols and sensor interfacing is done 3 2 1 Micro controller Programming The micro controller used is Atmel AVR 9088535 The AVR core combines a rich instruction set with 32 general purpose working registers All the 32 registers are directly connected to the Arithmetic Logic Unit ALU allowing two independent registers to be accessed in one single i
6. based on their research The driver contains a set of functions for sending and receiving SMS short message service text messages across a GSM network with a Nokia 51xx series phone We have only tested it with Nokia 5110 handset however it should work fine with any GSM phone in the series It should also work with the 3310 phones These functions were meant to be as portable as possible they contain no serial communications code and to perform two simple things send and receive SMS This code was meant to be small so that it could be used in our system To use setup the serial port and call init Then use smssend and smsrecv to send receive SMS messages All incoming SMS messages are deleted from the phone s inbox Copyright 2004 Defense Research amp Development Organization DRDO India 21 Embedded Network Client amp Data Acquisition System 3 2 1 4 PPP Implementation The Point to Point Protocol PPP provides a standard method for transporting multi protocol datagrams over point to point links PPP is comprised of three main components A method for encapsulating multi protocol datagrams A Link Control Protocol LCP for establishing configuring and testing the data link connection A family of Network Control Protocols NCPs for establishing and configuring different network layer protocols The PPP connection can be broken into several phases First establishment phase uses Link
7. 10 RTRIM64W Co O O O 0 GOOG TOGOG 0 0 Description DIODE DIODE DIODE DIODE Dual In Line VOLTAGE REGU VOLTAGE REGU Dual In Line Dual In Line Dual In Line Dual In Line Dual In Line Dual In Line Dual In Line VOLTAGE REGUL RELAY RELAY RELAY RELAY Trimm RESIST RESIST RESIST RESIST RESIST RESIST RESIST RESIST RESIST RESIST RESIST RESIST RESIST RESIST Trimm RESIST RESIST RESIST Trimm RESIST RESIST Trimm resistor TOR Am TOR Am TOR Am TOR Am TOR TOR TOR TOR TOR TOR TOR TOR TOR TOR resist TOR Am TOR Am TOR Am resist TOR Am TOR Am resisto 5 00000000000000000200020 RESIST Trimm TOR Ame resisto ATOR ATOR ATOR MOTOROLA OPTO COUP MOTOROLA OPTO COUP MOTOROLA OPTO COUP MOTOROLA OPTO COUP NPN Transisto NPN Transisto NPN Transisto NPN Transisto rican rican rican rican rican rican rican rican rican rican rican rican rican rican rican rican rican rican rican rican LER LER LER LER symbol symbol symbol symbol symbol symbol symbol symbol symbol symbol symbol symbol symbol symbol symbol symbol symbol symbol symbol symbol Copyright 2004 Defense Research amp Development Organization DRDO India 15 Embedded Network Client amp Data Acquisition System
8. 12345 Protocol j DF bool TRUE Fo Seek o 6 A Schksum MF bool FALSE d _ Actuator Driver rd s SgetData m amp yTTL int 115 Kane amp Protocol int UDP y SgetDatal psrcAddr long 192168 120 Sado T 7 QpdestAddr long lt 192 168 1 1 R SaddHeadei Modem Driver _ PPP Ae EM P ue C SsendCmat 7 k na ichar x FBUS s E PA ah eader s C Bhare char 7 KP T x 7 chksum odd r Schksum even NT Copyright 2004 Defense Research amp Development Organization DRDO India 6 Embedded Network Client amp Data Acquisition System VEM 1 1 reqData makePacket mitialize established Done 1 1 1 1 1 1 1 I i cormected sendPacket sendData 1 1 1 gt 1 Acknowledge i Acknowledge 1 1 i sendCorrmmand getPacket 1 1 decodePacket 1 1 1 i 1 I 1 1 1 1 1 1 Copyright 2004 Defense Research amp Development Organization DRDO India Embedded Network Client amp Data Acquisition System 3 makePacket 14 decodePacket 15 sendCormmand 1 reqData 2 data Micro Controll 7 connected 11 Acknowledge 7 16 Done 13 getPacket 8 sendPacket 12 sendCormrmand 10 Acknowledge 6 established Copyright 2004 Defense Research amp Development Organization DRDO India
9. Control Protocol LCP to detect and negotiate link options with the remote PPP NEGOTIATION WITH REQ computer Next the authentication phase ACK NAK AND REJ PACKETS verifies the User ID and password with Picmicro MCU Password Authentication Protocol PAP Although not one of the phases this is where ISPs negotiate compression M Establishing f Connection protocols The final phase is the network layer protocol Each protocol such as IP is configured with its control protocol like IPCP Control protocols are very similar for L _ Authenticating l if T LCP PAP CCP and IPCP but the protocol field is different and the options have pop ACEo 3 T different meanings Each packet can 9090 4 p request deny or accept a list of options gt and Address e l 16 52 2 6 Negotiation starts with either side requesting a list of options in a request REQ packet Each option consists of an Copyright 2004 Defense Research amp Development Organization DRDO India 22 Embedded Network Client amp Data Acquisition System option type byte length byte and option parameters If the receiving end likes all the options it replies with an acknowledge packet ACK If it doesn t like some parameters it responds with a negative acknowledge NAK packet that repeats all the options it rejects and replaces the rejected parameters with acceptable values If required options
10. W Simpson January 1994 e RFC 1661 The Point to Point Protocol PPP W Simpson Editor July 1994 e RFC 1663 PPP Reliable Transmission D Rand July 1994 e GSM 03 38 Alphabets and language specific information http webapp etsi org key queryform asp e The Linux Gnokii Project http www gnokii org e Wayne Peacock s Homepage http users senet com au wpeacock Copyright 2004 Defense Research amp Development Organization DRDO India 46 Embedded Network Client amp Data Acquisition System RFCs available online from sites like http www cis ohio state edu hypertext information rfc html Assigned PPP Numbers ftp ftp isi edu in notes iana assignments ppp numbers Copyright 2004 Defense Research amp Development Organization DRDO India 47 Embedded Network Client amp Data Acquisition System 7 REFERENCES Mr S C Sati Scientist E Grade DRDO Dighi Pune Dr N C Jain Senior faculty D Y P C O E Pune Mr Amol Bidve Developer amp VLSI Designer ST Microelectronics Noida Mr Anuj Kumar CTO Level E Tektics Pune Prof Leet Professor at University of Cleveland Ohio USA Copyright 2004 Defense Research amp Development Organization DRDO India 48
11. are missing those are added to the NAK reject list If some options are not recognized or are considered non negotiable they are rejected with the REJ packet that lists all the bad options The first side updates its option list and retransmits requests until it gets an ACK reply packet The other side can start negotiations at any time and the resulting link may have different options for each direction Terminate code reject protocol reject echo and discard control packet types are not implemented in this algorithm The details are broken down into a section for each control protocol The LCP options are negotiated first to establish the link A sample packet is shown below It has the normal PPP header of Ox7E OxFF 0x03 followed by OxCO 0x21 to indicate that the protocol is LCP The LCP packet consists of a code identification length and a list of options to configure followed by the standard 2 byte PPP CRC The code is a byte to indicate the meaning of the packet A list of codes is found in the Table shown The identification byte is incremented after each negotiation request which makes requests unique and connects them to the correct reply The 16 bit length is the number of bytes in the LCP packet four for the header plus the sum of the lengths of each option The list of possible options is again found in Table Each option is sent as a one byte option type followed by a one byte option length and an optional parameter The option l
12. network The scope of this project lies within the boundaries defined by the field instrumentation and the limitations imposed by the underlying hardware and the overall network systems and its sub systems Copyright 2004 Defense Research amp Development Organization DRDO India 2 Embedded Network Client amp Data Acquisition System 1 5 PROPOSED WORK The work we propose is to build an embedded system RTU with full fledged network stack to communicate with the CT The sensors would be attached to this RTU and the user will be able to communicate control monitor wit the sensors and actuators 1 6 SPECIFICATIONS 1 6 1 Electrical Specifications Supply Voltages DC a RTU 5V b Signal Conditioning Unit SCU 12 V 12 V c GSM modem 3 3 V 1 6 2 Input Specifications Input to the SCU must be in the range of 4 to 20 mA This is specifically designed for interfacing generic sensors Current implementation supports input for 4 sensors and controlled output for 4 actuators 1 6 3 Software Specifications Current implementation is a modest and scaled down version of UDP IP stack The Control Terminal Unit CTU has been implemented in Qt 3 0 environment under Linux According to Qt manuals this is portable to other platforms as well but not tested as such Copyright 2004 Defense Research amp Development Organization DRDO India 3 Embedded Network Client amp Data Acquisition System
13. terminal ready DTR pin must be set and the request to send RTS pin cleared e The F Bus Protocol and Commands The F Bus is bi directional serial type bus running at 115 200bps 8 data bits The serial cable contains electronics for level conversion and therefore requires power The first thing to do is supply power to the cable electronics and this is done by setting the DTR Data Terminal Ready pin and clearing the RTS Request to Send pin The next step is to synchronize the UART in the phone with your PC or microprocessor This is done by sending a string of 0x55 or U 128 times Simple hay The bus is now ready to be used for sending frames The Nokia protocol has a series of commands that allow the user to make calls send and get SMS messages and lots more Copyright 2004 Defense Research amp Development Organization DRDO India 30 Embedded Network Client amp Data Acquisition System Frame format for FBUS version 1 FrameID FrameLength MsgType block SeqNo ChkSum where FrameID 0x01 Command frame from computer to Nokia 0x02xxx Data call frame from computer to Nokia xxx 0x03 Data call frame from Nokia to computer 0x04 Command frame from Nokia to computer FrameLength block 2 MsgType see list SeqNum Sequence number of command in case where direction is from ME to computer the sequence number is counting from 0x30 to 0x37 and resetting back to 0x30 When direction is from comput
14. EQUEST PACKET 04 0014 06 userid 08 Pone 23 m FF oof aa 10 Lena 7E The complete packet 0000 7E FF 03 co 23 01 0010 08 70 61 73 73 e IPCP OPTIONS After LCP is negotiated and PAP is accepted the Internet Protocol must be configured The options are for IP address and IP Compression with more details in RFC 1332 IP address is option three and its 4 byte parameter is the Internet address of this node The server typically sends a request with option three followed by the IP address Otherwise the address is found by requesting an invalid choice like 0 0 0 0 and the server replies with a NAK and option three with the correct address A sample packet is shown below Some server implementations may request IP Compression Protocol option type two These requests are rejected because TCP is not implemented in this algorithm Copyright 2004 Defense Research amp Development Organization DRDO India 25 Embedded Network Client amp Data Acquisition System A SAMPLE IPCP NAK PACKET 03 06 CD C8 2D 4A NE NM G re Jonjo imum Ob as an Payload The complete packet 0000 7E FF 03 80 21 03 05 00 0A 03 0010 4D 7E e CCP OPTIONS Some servers will try to negotiate compression but since this algorithm is optimized for size instead of speed these requests are rejected The compression algorithms are complex and in some cases proprietary yet have little benefit on the short packets used in this algorith
15. Embedded Network Client amp Data Acquisition System 1 INTRODUCTION 1 1 PROBLEM DEFINITION The basic idea is to develop a data acquisition amp control system wherein an effort is to made to standardize the Remote Terminal Unit RTU hardware To encounter this problem the idea is to make a generic embedded device which would be interfaced with the sensors on one side and would be attached to some kind of network on the other end The problem definition for this project could be Design and implement a system which enables the user to monitor and control sensors and similar devices in a remote field with a computer interface 1 2 BACKGROUND In this project we are primarily interfacing sensors to be controlled and monitored Majority of the sensors used in the industry today have output specification as 4 to 20 mA corresponding to the actual value of the data sensed by the transducer The proposed RTU hardware functions as data acquisition unit thereby transmitting the data in its purest form to the Control Terminal CT The data interpretation and calibration is done at the CT according to the sensor type and can be changed by the user This makes the RTU generic enough to handle any kind of sensor falling in the 4 20 mA output specification 1 3CURRENT INDUSTRY PRACTICES Copyright 2004 Defense Research amp Development Organization DRDO India 1 Embedded Network Client amp Data Acquisition Sys
16. R ADMUX is set to input channel number and as for the start of conversion we set SFR ADCSR x040 On the completion of conversion the data is available in register ADCW which is a 10 bit value Copyright 2004 Defense Research amp Development Organization DRDO India 19 Embedded Network Client amp Data Acquisition System The ADC ISR interrupt ADC INT void adc isr void comes in to picture when the EOC is signaled As for the actuator again the major role to be played is the hardware for the control circuitry as detailed in the previous section The driver software has but little burden just to pass control to the relay thereby driving the actuator A simple port IO comes to play when the request is made to the system 3 2 1 2 Modem Driver Modem driver software is a program that initializes the modem at proper baud rate and then places a call to the ISP This driver mainly features functions related to the modem control by implementing standard AT commands The interface is a scaled down version of RS232 using 3 wire connection Unless the DTR amp RTS are pulled low the modem is not going to function properly so the hardware is designed so as to meet the above requirements All the communications with the modem is done through the micro controller UART The baud rate is set by putting appropriate values in the UBRR register refer MISC programming notes for details and serial communications is provi
17. but unnecessary for the most common communications The data may contain errors If the header checksum fails the internet datagram is discarded at once by the entity which detects the error The internet protocol does not provide a reliable communication facility There are no acknowledgments either end to end or hop by hop There is no error control for data only a header checksum There are no retransmissions There is no flow control Errors detected may be reported via the Internet Control Message Protocol ICMP which is implemented in the internet protocol module Copyright 2004 Defense Research amp Development Organization DRDO India 29 Embedded Network Client amp Data Acquisition System 3 2 1 7 FBUS Implementation M Bus F Bus predecessor is a one pin bi directional bus for both transmitting and receiving data from the phone It is slow 9600bps and only half duplex Only two pins on the phone are used One ground and one data M Bus runs at 9600bps 8 data bits odd parity one stop bit The data terminal ready DTR pin must be cleared with the request to send RTS This powers the electronics in the cable and I think it sets it for M Bus operation F Bus is the later high speed full duplex bus It uses one pin for transmitting data and one pin for receiving data plus the ground pin Very much like a standard serial port It is fast 115 200bps 8 data bits no parity one stop bit For F Bus the data
18. cross compiler was finalized i e Code Vision Most of the initial programming was done in assembly using AVR Studio4 The prominent I O Registers that deal with UART programming are UBRR UDR and USR amp UCR The standard C language I O functions were adapted to work on embedded micro controllers with limited resources The lowest level Input Output function s are char getchar void returns a character received by the UART using polling void putchar char c transmits the character c using the UART using polling Prior to using these functions you must Initialize the UART s Baud rate Enable the UART transmitter Enable the UART receiver Example include 90s8515 h include lt stdio h gt quartz crystal frequency Hz define xtal 4000000L Baud rate define baud 9600 void main void char k initialize the UART s baud rate UBRR xtal 16 baud 1 initialize the UART control register RX amp TX enabled no interrupts 8 data bits UCR 0x18 while 1 receive the character k getchar and echo it back putchar k Copyright 2004 Defense Research amp Development Organization DRDO India 39 Embedded Network Client amp Data Acquisition System All the high level Input Output functions use getchar and putchar Copyright 2004 Defense Research amp Development Organization DRDO India
19. ded by primitives putchar getchar to send and receive a single byte 3 2 1 3 GSM Driver Apart from the standard AT commands there are special extended set of at commands for the GSM modems most of which are preparatory However the main purpose of this driver is to send and receive SMS Placing a data call through a GSM modem is out of the question The GSM driver implementation has come in two different flavors Implementation of AT C commands Copyright 2004 Defense Research amp Development Organization DRDO India 20 Embedded Network Client amp Data Acquisition System Implementation of proprietary Nokia FBUS MBUS protocols Implementation of the former is much similar to the Modem driver as the only thing required was to deal with the proper AT C command The sequences of functions were designed to initialize the modem in text mode rather than dealing in the PDU protocol data unit mode followed by functions to send and receive SMS Note we have specific AT C commands for the primitives such as read delete SMS and like While the programming for GSM driver using the AT C commands was not only easy but efficient however the discovery was a bit delayed it was the FBUS MBUS Nokia protocols that were cracked first Thanks goes to the gnokii http www gnokii org team for figuring out the frame format among many other things Although this driver was written from scratch it was heavily
20. ength is two for the option header plus the number of bytes in the parameter Copyright 2004 Defense Research amp Development Organization DRDO India 23 Embedded Network Client amp Data Acquisition System A SAMPLE LCP REQUEST PACKET The complete packet with more option details 0000 7E FF 03 CU 21 01 0010 04 co 23 05 06 71 Same LCP packet with escape sequences 0000 7E FF 7D 23 CO 21 0010 26 7D 20 7D 2A 7D 0020 25 7D 26 71 AE BE 0030 64 7E LCP NEGOTIATION CODES 8 E Rron O O 5 emmeAk S 8 jPeeoReed E s EmReues E 19 EmeRey E I jDsavReues RFCMB Copyright 2004 Defense Research amp Development Organization DRDO India Embedded Network Client amp Data Acquisition System e PAP OPTIONS The PAP details can be found in RFC 1334 For this algorithm they were simplified to one packet exchange The PAP packet is similar to LCP with 0xC023 instead of OxC021 in the protocol field Instead of negotiating options only the User ID and password are sent as a request If the server acknowledges then the user is logged in A NAK reply would mean that the User ID or password is incorrect The format can be seen in figure shown The first payload byte is the length of the User ID followed by the User ID The password is appended in the same way Length first followed by password A SAMPLE PAP R
21. er to ME sequence number counts from 0x08 to OxOf and resets back to 0x08 It may not be required to be this way Sequence numbers are used in acknowledging commands ChkSuml CRC 0 for i120 i lt 2 CMD_LEN i CRC frame i Frame format for FBUS version 2 Direct IRDA FrameID DestDEV SrcDEV MsgType 0x00 FrameLength block FramesToGo SeqNo PaddingByte ChkSum1 ChkSum2 where FrameID Oxl1c IR FBUS Oxle Serial FBUS DestDev SrcDev 0x00 mobile phone O0xOc TE FBUS eg PC MsgType 0x02 SMS handling s Send SMS message 0x0001 0x02 0x00 SEND REQUEST r Message sent 0x0002 Copyright 2004 Defense Research amp Development Organization DRDO India 31 Embedded Network Client amp Data Acquisition System r Send failed 0x0003 error code s Get SMS message 0x0007 0x02 location 0x01 0x64 s Initiate connection 0x000d 0x00 0x00 0x02 r Initiate ACK 0x000e 0x01 r SMS message received 0x0010 whole message FrameLength block 2 1 if PaddingByte exists FramesiToGo 0x01 means the last frame SeqNo UX X Y X 4 first block 0 continuing block Y sequence number PaddingByte 0x00 if FrameLength would be an odd number anyways it doesn t exists e SMS Point to Point Character Packing GSM 03 38 Alphabets and Language Specific Format is the technical specification that describes the packing of 7 bit c
22. es to destinations where sources and destinations are hosts identified by fixed length addresses The internet protocol also provides for fragmentation and reassembly of long datagrams if necessary for transmission through small packet networks The internet protocol uses four key mechanisms in providing its service Type of Service Copyright 2004 Defense Research amp Development Organization DRDO India 28 Embedded Network Client amp Data Acquisition System Time to Live Options Header Checksum The Type of Service is used to indicate the quality of the service desired The type of service is an abstract or generalized set of parameters which characterize the service choices provided in the networks that make up the internet This type of service indication is to be used by gateways to select the actual transmission parameters for a particular network the network to be used for the next hop or the next gateway when routing an internet datagram The Time to Live is an indication of an upper bound on the lifetime of an internet datagram It is set by the sender of the datagram and reduced at the points along the route where it is processed If the time to live reaches zero before the internet datagram reaches its destination the internet datagram is destroyed The time to live can be thought of as a self destruct time limit The Options provide for control functions needed or useful in some situations
23. ged without unintentionally changing the direction of any other pin with the SBI and CBI instructions The same applies for changing drive value if configured as output or the enabling disabling of pull up resistors if configured as input Three I O memory address locations are allocated for each Port one each for the Data Register PORTx Data Direction Register DDRx and the Port x Input Pins PINx The Port x Input Pins address is read only while the Data Register and the Data Direction Register are read write UART Programming As per the 8535 data sheet the AT90S8535 features a full duplex separate receive and transmit registers Universal Asynchronous Receiver and Transmitter UART The main features are Baud rate generator that can generate a large number of baud rates bps High baud rates at low XTAL frequencies 8 or 9 bits data Noise filtering Overrun detection Framing Error detection False Start Bit detection Three separate interrupts on TX Complete TX Data Register Empty and RX Complete One of the striking reasons for choosing AVR micro controller was its in built programmable UART and its ease of programming although using a cross compiler hides Copyright 2004 Defense Research amp Development Organization DRDO India 38 Embedded Network Client amp Data Acquisition System the complexity that arises in assembly programming it certainly helped until a suitable
24. haracters and shows the standard character map Packing ASCII into 7 bit characters is a pain but is quite easy to do Here is a quick example Let s say we want to decode the string hello First hello is displayed in hexadecimal using the character map provided in GSM 03 38 For A to Z and numbers it is just the standard ASCII conversion h e 1 jJ O ASCII characters 68 65 6C 6C 6F In hexadecimal 1101000 1100101 1101100 1101100 1101111 In Binary When dealing with binary it makes life easier to write everything backwards The first byte in the string is on the right The least significant bit is then displayed on the left with Copyright 2004 Defense Research amp Development Organization DRDO India 32 Embedded Network Client amp Data Acquisition System the most significant bit on the left Shown below is the same string of hello just displayed backwards Then it s just a matter to dividing the binary values into bytes starting with the first character in the string Start from right and go to left The first decoded byte is simply the first 7 bits of the first character with the first bit of the second character added to the end as shown below The next decoded byte in then the remaining 6 bits from the second character with two bits of the third byte added to the end This process just keeps going until all characters are decoded The last decoded byte is the remaining bits from the last characte
25. ion DRDO India 14 Embedded Network Client amp Data Acquisition System 3 1 4 Bill Of Material Signal conditioning and power supply board Part Value D1 1N4004 D3 1N4004 D4 1N4004 D5 1N4004 TEL IC2 IC3 ICA TES IC6 TC IC8 TCI IC10 TOELT K1 G5L K2 G5L K3 G5L K4 G5L OK2 4N37 OK3 4N37 OK4 4N37 OK5 4N37 BC547 BC547 BC547 BC547 ZUG uU W 9 9 WQ 0 GO OO C 9 0 Ov Oi E LO KM a H E 2 A 9999999999 S ve N H co LO R21 R22 R23 R24 R25 Device 1N4004 1N4004 1N4004 1N4004 DIL8 78XXL 78XXL DIL8 DIL8 DIL8 DIL8 DIL8 DIL8 DIL8 78XXL G5L G5L G5L G5L 4N37 4N37 4N37 4N37 BC547 BC547 BC547 BC547 R TRIMM6A4W ZW a Zu R TRIMM6 4W R TRIMM6 4W R TRIMM6 4W R TRIMM6 4W US_0207 1 US_0207 1 US_0207 1 US_0207 1 US_0207 1 US_0207 1 US_0207 1 US_0207 1 US_0207 1 US_0207 1 US_0207 1 R US_0207 1 R US_0207 1 R US_0207 1 R US_0207 1 R US_0207 1 R US_0207 1 R US_0207 1 R US_0207 1 R US_0207 1 e a e a aeae a a e a a a Re Ce Ce Package DO41 10 DO41 10 DO41 10 DO41 10 DILO8 78XXL 78XXL DILO8 DILO8 DILO8 DILO8 DILO8 DILO8 DILO8 78XXL G5LE G5LE G5LE G5LE DILO6 DILO6 DILO6 DILO6 TO92 TO92 TO92 TO92 RTRIM64W 0207 10 0207 1 0207 1 0207 1 0207 1 0207 1 0207 1 0207 1 0207 1 0207 1 0207 1 0207 1 0207 1 0207 1 RTRIM64W 0207 10 0207 10 0207 10 RTRIM64W 0207 10 0207 10 RTRIM64W 0207
26. is In System Programmable Flash memory The device is manufactured using Atmel s high density nonvolatile memory technology The on chip In System Programmable Flash allows the program memory to be reprogrammed in system through an SPI serial interface or by a conventional nonvolatile memory programmer By combining an enhanced RISC 8 bit CPU with In System Programmable Flash on a monolithic chip the Atmel AT90S8535 is a powerful micro controller that provides a highly flexible and cost effective solution to many embedded control applications The AT90S8535 AVR is supported with a full suite of program and system development tools including C compilers macro assemblers program debugger simulators in circuit emulators and evaluation kits Micro controller programming consists of sensor driver GSM driver modem driver LCD driver PPP implementation UDP implementation IP implementation and application layer implementation 3 2 1 1 Sensor Driver The sensor driver circuit is elaborated in the previous section which comprises of signal conditioning I V unit where by the analog voltage is fed to the inbuilt ADC within the micro controller Whenever the system is requested for the data from the desired channel it s actually a simple A to D conversion of the analog signal at input channel O of the micro controller Then the sensor driver software is responsible for the proper functioning of the ADC The special function register SF
27. ls for the hardware were incorporated in to the project Copyright 2004 Defense Research amp Development Organization DRDO India 41 Embedded Network Client amp Data Acquisition System 4 USER MANUAL 4 1 OPERATING PROCEDURE The embedded host operates in two modes One is over UDP IP and other is over GSM network 4 1 1 Operations over UDP IP The monitor tool montoo when started tries to connect to the embedded web host using ARP It contains the MAC address of the host and locates its IP address When connected the host authenticates the user and waits for the request On request of user montoo sends request command to the host and retrieves data The time to live or the time montoo waits for the answer is around 15 seconds after which it reports the user about the disconnection If it gets the requested data within 15 seconds it shows he value as well as graph to the user Montoo operates over UDP IP and sends request packets after every time interval which can be adjusted by the user 4 1 2 Operations over GSM With any mobile phone operating over GSM network can retrieve data from the embedded web host using Short Messaging Service SMS For retrieving data of sensor 1 send an SMS to the web host number with text DATA1 On receiving this SMS the embedded web host would respond to the sender with the data of sensor 1 via SMS Copyright 2004 Defense Research amp Developme
28. m Choosing the puddle jumper option type 3 means that no compression or decompression is required Copyright 2004 Defense Research amp Development Organization DRDO India 26 Embedded Network Client amp Data Acquisition System 3 2 1 5 UDP Implementation Its simplicity and bandwidth efficiency make it an important part of some multimedia Internet protocols This project supports UDP protocol as we had limited amount of memory on chip First of all UDP is an unreliable protocol not that it should be avoided but rather that packets can get lost without warning and may require retransmission It is deterministic in the sense that each packet or timeout triggers the next event without regard to what state the connection is in This simplifies programming and makes debugging much easier There are 20 bytes of IP header then 8 bytes of UDP header and the UDP data The first two 2 byte fields are the source and destination port numbers The port numbers are important to identify what process gets the UDP data The next two bytes are the UDP length eight bytes of UDP header plus the length of the UDP data This value is redundant because it can be calculated from the IP header by subtracting the header length from the total length The last 2 bytes of the UDP header are the 16 bit one s complement checksum of the pseudo header the UDP header and the UDP data The pseudo header is not transmitted but the following 12 by
29. nformation can also be viewed The Keypad makes the LCD menu driven thus providing the basic functions like scrolling through the sensor data to selection of the transfer mode UART Multiplexing and Level Conversion The micro controller provides only one serial asynchronous communication port Now to communicate with more than two serial devices we have done multiplexing of the serial port After selection of the device by controlling the multiplexer the Uart level is converted to RS 232 standard so that it can be interfaced to the GSM module and dial up modem 3 1 2 External Peripherals LCD 16X2 Keypad 4 key GSM Module Nokia Siemens Dial up Modem Zoltrix Copyright 2004 Defense Research amp Development Organization DRDO India 11 Embedded Network Client amp Data Acquisition System 3 1 3 Interfacing Circuitry e Schematic Micro controller Board N4004 p 1NA0Qx LCD DATA P PD amp OC1B PD4 INT1 PD3 INTO PD2 TXD PD1 RXD PDO LCD Control Copyright 2004 Defense Research amp Development Organization DRDO India 12 Embedded Network Client amp Data Acquisition System Copyright 2004 Defense Research amp Development Organization DRDO India 13 Embedded Network Client amp Data Acquisition System Copyright 2004 Defense Research amp Development Organizat
30. nstruction executed in one clock cycle The resulting architecture is more code efficient while achieving throughputs up to ten times faster than conventional CISC micro controllers The AT90S8535 provides the following features 8K bytes of In System Programmable Flash 512 bytes EEPROM 512 bytes SRAM 32 general purpose I O lines 32 general purpose working registers flexible timer counters with compare modes internal and external interrupts a programmable serial UART programmable Watchdog Timer with internal oscillator an SPI serial port and two software selectable power saving modes The Idle Mode stops the CPU while allowing the SRAM timer counters SPI port and interrupt system to continue functioning The Power down Mode saves the register contents but freezes the oscillator disabling all other chip functions until the next external interrupt or hardware reset AT90S8535 features include in built UTC and a 10 bit ADC with 8 channels The AVR uses a Harvard architecture concept with separate memories and buses for program and data The program memory is executed with a two stage pipeline While one Copyright 2004 Defense Research amp Development Organization DRDO India 18 Embedded Network Client amp Data Acquisition System instruction is being executed the next instruction is pre fetched from the program memory This concept enables instructions to be executed in every clock cycle The program memory
31. nt Organization DRDO India 42 Embedded Network Client amp Data Acquisition System This facility is specifically provided for the situations where the user may not have access to the monitoring tool or Internet This facility is helpful for retrieving data on the move Copyright 2004 Defense Research amp Development Organization DRDO India 43 Embedded Network Client amp Data Acquisition System 5 CONCLUSION 5 1 DEVELOPERS COMMENTS The project did work out as expected But the major thing that should be appreciated is the GSM interfacing network protocol stack UDP IP implementation FBUS protocol implementation and everything at micro controller level This project exposed us to many new arenas of engineering and especially computer filed The new thing to learn from the project apart from syllabus is the embedded environment programming Other values we got from the project is working as a team member and bringing out some collective output 5 2 FUTURE ENHANCEMENTS Though few drawbacks exists in the system the source of which is primarily dial up connection and the limitations that come along with it most of them could be removed by the use of Ethernet LAN controller Software for the network controller remains exactly same and only additional driver for LAN controller needs to be written Applications of the product as a whole are immense web based router and firewall configuration t
32. o name a few but can be enhanced further by incorporating HTTP over TCP which were not implemented due to memory constraints At present the micro controller programming has been done right from the scratch using a C cross compiler Therefore the efficiency of the system as a whole could not be Copyright 2004 Defense Research amp Development Organization DRDO India 44 Embedded Network Client amp Data Acquisition System compared with any existing system This could be standardized by using standard real time operating system like RTLinux Vxworks or alike Copyright 2004 Defense Research amp Development Organization DRDO India 45 Embedded Network Client amp Data Acquisition System 6 BIBLIOGRAPHY e Atmel 8535 data sheet http www atmel com e Atmel Application notes http www atmel com e Embedded Ethernet http www embeddedethernet com e Help manuals of Code Vision http www infotech ir ro e W R Stevens TCP IP Illustrated Vol 1 Addison Wesley Reading MA 1994 e RFC 0768 User Datagram Protocol J Postel Aug 28 1980 e RFC 0791 Internet Protocol J Postel Sep 01 1981 e RFC 1071 Computing the Internet checksum R T Braden D A Borman C Partridge Sep 01 1988 e RFC 1332 The PPP Internet Protocol Control Protocol IPCP G McGregor May 1992 e RFC 1334 PPP Authentication Protocols B Lloyd W Simpson October 1992 e RFC 1570 PPP LCP Extensions
33. o or read from the DD Oo 0 Boe 0 mE Oo HEN EM o RAMI CG RAM The display does not shift Write Data to CG RAM DD RAM Writes O on the home position cursor shifts to the next position oi og Copyright 2004 Defense Research amp Development Organization DRDO India 36 Embedded Network Client amp Data Acquisition System Wait for more than 15ms for V bo ris da d Gy RS RAT O8 Da DB Ca DH DB OB D8 EN EE o EN C c 9 c NJ preon Sat Wait Tor more than 3 1 ma pA OF Ca DB DA Ca Da Function Set ti BF cannot be checked before this inslruclinn BF can be checked after this HS RW DB Da DB DB DB DB DE D8 instruction When BF is not checked the wailing time between instructions is longer than the execulion iik 0 0 0 o 1 N F t Function Set see foot nate CursoriDisplay Shift Display ONIOFF Control an Mode Se SWS EN o o E o Clear Display Initiaiation Ents Mate Specify the number of display lines and character font The number of display lines and character font cannot be changed afterwards Copyright 2004 Defense Research amp Development Organization DRDO India 37 Embedded Network Client amp Data Acquisition System e 8535 Programming Notes I O Ports All AVR ports have true read modify write functionality when used as general digital I O ports This means that the direction of one port pin can be chan
34. om sensor 2 Copyright 2004 Defense Research amp Development Organization DRDO India 34 Embedded Network Client amp Data Acquisition System 3 2 1 9 Miscellaneous Programming Notes e LCD Interface amp Driver Below is the interfacing block diagram of the LCD display module with the micro controller The actual interface is shown in the hardware design section where Port C of 8535 is used as the data bus for the LCD while the control lines RS RW enabled are provided by PD 5 PD 6 PD 7 respectively BLOCK DIAGRAM vss 5 V Vuo LED BACKLIGHT The software associated for driving the LCD is greatly adopted from the method as illustrated in textbook by Gaonkar Following are the notes that further elucidate the micro controller programming for LCD Copyright 2004 Defense Research amp Development Organization DRDO India 35 Embedded Network Client amp Data Acquisition System 8 bit Operation 8 character 2 line Display Example INSTRUCTION CODE LCD DISPLAY DESCRIPTION Turn on the power initialized by the internal reset No display initialization Function set Set data length number of displa line and character font 8 bit oo0007170XX length 2 line display 5 x 7 dots Display ON OFF The display and the cursor are turned ON 00000021 1 1 On initialization entire display is filled with spaces Entry Mode set Increments the DD RAM address by 1 when a character code is written int
35. r drives the relay circuitry This circuit provides current amplification for driving relay coil The opto coupler provides the isolation of the circuitry The four channel control of the relay can be used to drive the actuators Micro controller Unit The micro controller does all the processing of information ADC and provides interface to peripherals The data from the sensor interface circuit 0 5V is converted to the digital form by programming the internal 10 bit ADC Now the task of micro controller is to transfer that data Micro controller programming consists of sensor driver GSM driver modem driver PPP implementation UDP implementation IP implementation and application layer implementation It also provides the interface to peripherals like LCD keypad and chip programmer Implementing and programming the internal UART ports do serial communication The on off control to the relay is provided by reading the data packets from the end user The data from the micro controller can be transferred to GSM Copyright 2004 Defense Research amp Development Organization DRDO India 10 Embedded Network Client amp Data Acquisition System by using Nokia F Bus Version 2 protocols and to the modem by implementing IP and UDP The entire protocol stack is implemented in the micro controller LCD and Keypad Interface LCD provides the display of the field data and other related information The connection and status i
36. r with the most significant bits packed with zeros 6F 6C 6C 65 68 101111 1101100 1101100 1100101 1101000 LA The ASCII characters shown in binary 10 11111101 10011011 00110010 11101000 bh The above binary just split into 8 bit segments 06 FD 9B 32 E8 The 8 bit segments decoded into hex The message hello is therefore E8 32 9B FD 06 when packed When playing with sending SMS messages a lot of decoding is required Therefore we wrote a few small programs to automatically pack and unpack the data 3 2 1 8 Application Layer Implementation The job of the application program running inside the embedded host is to provide the sensor data to the request coming to it via modem or GSM network For this the application continuously polls the incoming packets from the dial up lines and from the GSM network The application is prepared to respond to the requests which are in a specific format The format typically is SREQ Here REQ is to be replaced by the data to be retrieved On receiving the request the host retrieves the data and replies back On a dial up connection Copyright 2004 Defense Research amp Development Organization DRDO India 33 Embedded Network Client amp Data Acquisition System the host replies back with a UDP packet whereas for a request on GSM network the host replies via SMS Examples DATAI to retrieve the data from sensor 1 DATA2 to retrieve the data fr
37. tem Currently the proprietary systems that exist in the industry are more hardware oriented and are specific to a given sensor There are various implementations and standards proposed which can be used to build an RTU But the major drawback of these systems is that they are not very generic and changing a single sensor may lead to changing the entire hardware unit Field buses link sensors and actuators at process level with the system intelligence i e with DCS systems PLCs and controllers so that the information they supply can flow into the factory information system At the moment there is no standardized information system which performs this task while at the same time being the part of the factory s wider information network What does exist is largely based on the efforts of individual companies of interests groups The aims of standardization are therefore twofold a Instruments of various manufacturers must be able to operate on the same network as is the case for the 4 to 20 mA interface but using th full functionality of bi directional digital communication b There networks must be linked to production automation and commercial data processing systems such as MAP and Top so that e g Just in Time material stocking and the tuning of output to actual order volume can be implemented 1 4 OBJECTIVE amp SCOPE Objective of this project is to make a generic RTU that should be able to commute with the user over a
38. tes are added to the checksum anyway The 32 bit source and destination addresses the 16 bit UDP address and the 8 bit protocol field are extended to 16 bits to ensure that the UDP data is going to the correct IP address The checksum is optional and set to zero if not used Since zero means no checksum then a valid checksum that adds up to zero must be inverted to OxFFFF If the UDP data is an odd number of bytes your 16 bit checksum routine will need to pretend that there is an extra byte 0x00 at the end The format of the UDP data will depend on which port you are connecting to and which protocol is using the data Copyright 2004 Defense Research amp Development Organization DRDO India 27 Embedded Network Client amp Data Acquisition System THE UDP PACKET FORMAT Buffer bit Offset 0 4 IP Header 24 Source Port Number Destination Port Number 28 UPD Length UDP Checksum 32 UDP Data Such as TFTP The IP Packet Format bit bit bit bit bit 0 8 16 24 31 4 IP Version Length Type of Service Total Length in Bytes 8 Identification Fragment Offset 12 Time To Live TTL Header Checksum 16 Source IP Address 20 Destination IP Address 24 ICMP TCP or UDP Header and Data 3 2 1 6 IP Implementation The Internet Protocol is designed for use in interconnected systems of packet switched computer communication networks The internet protocol provides for transmitting blocks of data called datagrams from sourc
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