Homework 10: Software Design Considerations
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1. followed by a length 0x02 followed by the status which is OxOC when in read mode followed by the 8 bytes for the ID tag followed by the BCC mask which is discarded The code was designed so that it waits in a loop until the start byte is received SerEgetc is used to read in individual bytes Once the start byte is received the function waits for the length byte followed by the status byte If all of these bytes are what they should be serEread is called which is capable of reading in a specified number of bytes 8 in this case to an array of unsigned integers in our case If the system is in normal mode comparetags is called to see if the tag scanned in matches a preexisting entry If the tag corresponds to a preexisting entry then that user is logged on and all bills accepted and flows tracked will be applied to that account The users information will be displayed on the lcd with a call to the Icd function If the ID tag does not exist in the system a call to Icd will be made displaying access denied If the system is in add user mode the next tag scanned will be associated with the user being added after the tag is checked against preexisting tags If the tag already exists in the system and option to remove the tag from the old user and associate it with the new user will be presented as well as an option to choose a different tag Also when a tag is scanned in their BAC level will be checked and if the level is higher than the l2. heap will be located on the 512K of SRAM Also web pages and images will be loaded into the SRAM from the serial flash during program execution This should be plenty of memory to accommodate everything since the largest portion will be used by images and web pages which won t be more than 50 100K User data and the consumption log consisting of time date amount and user name per entry will be written to serial flash at a specified time so that it will be saved when the unit is shut down Depending on how much space is available on the SRAM the consumption log will be added to the saved log on the serial flash A daily dumping of this log will probably be sufficient for memory conservation Since Dynamic C handles all memory mappings and layout details when the code is compiled most of the complex memory mapping scheme is hidden from the user Rabbit instructions access 64K memory spaces which use 16 bit address fields making a more compact code that executes faster than using a larger address field The figure below shows how memory is accessed from the processor to the memory chip A 16 bit address comes out of the processor and a 20 bit address is created from the memory mapping unit This 20 bit address is used to directly access the memory chips 1 Memory Memory Laie Memory Processor Mapping Interface ni Chips Unit 20 bits plus control Figure 2 2 1 Addressing Memory Components All program code and const
3. the 64 bit ROM code is sent to all of the devices The ROM code corresponds to a particular probe Whichever probe that the ROM ECE 477 Digital Svstems Senior Design Project Spring 2006 code corresponds will respond In order to transmit data each bit must be held for 45us This is done using the tempsendbit function we created Tempsendbit uses for loops to create the delav between reads and writes The delav was tested using an oscilloscope If needed the function mv disable interrupts upon being called to keep the delav consistant The function tempsendbyte uses tempsendbit to send a byte of data To send the ROM code tempsendbvte 0x55 must be called to get the probe ready to read a ROM code then tempsendbyte must be called 8 times with the appropriate bytes of the ROM code Once the ROM code has been sent tempreadbyte must be called 8 times The first two bytes represent the temperature the rest are other diagnostic information about the probe Tempreadbyte returns a byte of data received from the probe It works similarly to tempsendbyte except that the port is set to input rather than output and tempreadbit is called instead of temsendbit It was unsure initially as to whether or not switching the pin between input and output would happen quickly enough but initial testing has shown that this method will work The temperature is stored in the first byte of data with bit 0 being the 5 C and bit 7 being 2 The second byte
4. C and 115200 for the Icd screen on port D Then serXparity PARAM_EPARITY is called to set port C to even parity for the bill acceptor and serXparity PARAM_NOPARITY is called to set ports D and E to no parity for RFID and the led Finally serXwrflush and serXrdflush are used to clear out the serial port buffers To set up the i o pins for read and write WrPortI is used to write the appropriate bits to the pins control register Also an interrupt vector must be initialized for use with the flow meters The vector is set up to call flowmeter each time a high to low or low to high occurs on the specified pin It will then run initialization sequences for the thermometers RFID bill acceptor and LCD to set them up for use and make sure they are functioning properly If any device fails to initialize correctly init returns 0 else a 1 It also initializes any global variables used throughout the program Since Dynamic C handles all memory initializations and allocations there is no need for any code to organize the memory layout All of the initializations are written in test code for each device The initializations for each device simply need to be moved into the init function validator The validator function is called in a while loop in the main function Its purpose is to accept or reject bills inserted into the bill acceptor and credit the amounts to the correct user account The function waits in a loop calling serCgetc until n
5. Homework 10 Software Design Considerations Due Friday March 31 at NOON Team Code Name D R LN K Team Member Completing This Homework Justin Thacker E mail Address of Report Author jbthacke Group No purdue edu Evaluation Component Criterion Score Multiplier Points Introduction amp Summary 0123456789 10 X1 Software Design Considerations 012345678910 X3 Software Design Narrative 012345678910 X3 List of References 012345678910 X1 Appendices 012345678910 X1 Technical Writing Style 012345678910 X1 TOTAL Comments ECE 477 Digital Svstems Senior Design Project Spring 2006 1 0 Introduction The Digital Real time Intelligent Networked Kegerator is a complex integration of electrical components through a microprocessor In order for the components to communicate with the RCM3315 along with each other a great deal of software must be implemented The svstem will be event driven and will need to respond in real time When a user scans an RFID tag or inserts a bill the system needs to be able to respond immediately and not only make changes to the state of the microprocessor but make changes to peripherals such as the Icd When a flow meter is activated the microprocessor needs to know not only that beer is flowing from a tap but also which tap its flowing from and which user is using the tap Since each component critically relies on information supplied by the
6. ant data is stored onto the 512K Flash memory section and variable data and the stack and heap are stored on the SRAM It uses a paging scheme to access code beyond the reach of a 16 bit address using an 8K sliding page XPC segment and register It also utilizes separate I and D Instruction and Data spaces which results in increased data and code by sharing addresses but not the same physical memory space This is illustrated in the figure below Be ECE 477 Digital Svstems Senior Design Project Spring 2006 20 Bit Memorv Space xpe window stack D Space Variable D Space I space Constant D Space Figure 2 2 2 Separate I and D Spaces Physical memory on the Rabbit is also separated into various segments The Base Segment typically 24KB holds short subroutines interrupt routines and BIOS initialization code Itis mapped to the RAM The Data Segment typically 28KB is also mapped to RAM and holds Dynamic C variables It starts at 24KB and ends at 52KB 0xD000 Data allocation starts at the top and moves downward The Stack Segment typically ranges from 0xD000 to OxDFFF is mapped to the RAM and holds the system stack The Extended Memory Segment is 8KB and ranges from 0xE000 to OxFFFF It is used to execute extended code and can also hold data The figure below provides an illustration XMEM Segment Stack Segment 0xD000 0xD000 Data Segment Instruction Space Data Spa
7. ce 0xD000 Data Segment Data Segment Root Code Root Data 0x3000 0x0000 16 bit Logical Address Space Figure 2 2 3 Memory Segments 0x3000 Base Segment Root Code Base Segment Constants 0x0000 External Interface Mapping Port Pins Description Direction PA0 PA2 PA4 PA6 Each of 4 flow meters routed to pins I PEO Pin for flow meter interrupt I ECE 477 Digital Svstems Senior Design Project Spring 2006 PB4 Temperature probe bus I PA1 PA3 PA5 PA7 Each of 4 solenoids routed to pins O PF Quadrature input for rpg PB2 Actuator controlling compressor O Serial PC Serial port for bill acceptor VO Serial PD Serial port for LCD screen I O Serial PE Serial port for RFID module VO Serial PG Serial port for thumb reader 3 0 Software Design Narrative init Init is the first function called in the main program Its purpose is to initialize all ports pins and global variables used in the system It sets the serial ports C D and E to their proper baud rates and settings and configures the appropriate pins for input and output for use with the actuator temperature probes and flow meters The serial ports are configured using the following Dynamic C functions First serXopen baud_rate where X corresponds to the port letter opens the serial port and sets it to the baud rate specified 9600 for RFID on port E 9600 for the bill acceptor on port
8. erature probes will be set to run every minute This will be accomplished by placing the temperature probe routine inside of a costate statement that is inside the main loop Also inside of this costate will be a DelaySec 60 so that the function is called once a minute or close to that The purpose of the costate is so that context switching between the main loop and the costate will occur keeping the delay accurate and not halting the entire loop for a minute A blood alcohol adjustment routine will be called once every few minutes It will be implemented much like the temperature probes in a costate statement with some sort of delay Finally the rpg routine as well as the flow meter routine will be called when an interrupt occurs The interrupt service routine for each of the peripherals will handle the request properly The LCD routine will be called as needed within each of the previously stated routines We chose to use polling for the bill acceptor and rfid because their use is real time and can occur at any moment Also there were no interrupts available to use The flow meter routine was the only routine where an interrupt was critical to its implementation ECE 477 Digital Svstems Senior Design Project Spring 2006 Memorv Mapping The main program code will be stored in the 512K of Flash memorv Since Flash is non volatile and has a limited number of uses it is the optimal location to store the code file Program variables program stack and
9. ew data is received It will then use a switch statement to decode the input from the device into either a bill type or an error If the bill is acceptable serCputc 0x02 is called to tell the bill acceptor to keep the bill If the bill is not acceptable serCputc OxOF is called to tell the bill acceptor to reject the bill Upon receiving an acceptable bill the add_credits function is called with the appropriate bill 4 ECE 477 Digital Svstems Senior Design Project Spring 2006 code Credits are then added to the current user s account The lcd function will also be called and will display the dollar amount received on the Icd screen or an error message if an error has occurred Test code has been written that will successfully decode the value of the bill and either accept or reject it Code has not yet been written for add_credits or the lcd function Basic functionality of the lcd has been tested though by sending basic strings to the lcd using serDputc with the Icd hooked up rf id The rf id function is the first function to get called in the main while loop Its purpose is to determine if a new RFID tag has been scanned validate the user and log them onto the system The rf_id function may also be called when a new user does not yet have an RFID tag and needs to have one associated with his account When an RFID tag is scanned a sequence of bytes is sent from the RI STU MRDI to the rabbit The sequence is a start byte 01
10. imit 08 the solenoids will be activated by the lock function closing off access for that user to the taps The status of each of these events will be updated on the Icd The current rf_id routine is currently implemented as a stand alone routine which is capable of scanning in a new tag adding that tag to the system and then recognizing the user when the tag is scanned again temp_probe The temp_probe function gets called every minute from the while loop in the main function The function call will be placed inside a costate statement along with a DelaySec 60 which will allow the function to be called approximately every 60 seconds Its purpose is to determine the temperature of each probe and determine if the compressor needs to be run or not The temp_probe function will be able to access more than one probe on a single pin In order to access a temperature probe the address of the probe must be known prior to using it Each function call will access each probe in order starting with probel The inittemp function must be called before reading each probe so it will be called 3 times per function call if three probes are present Inittemp simply sets the pin being used to output and pulls the output pin low for half ams The pin is then set to input and the function waits at least 60 us before reading the input from the device A 0 means the device is ready and a 1 means something is wrong Once the inittemp function has been called
11. other components the system must be kept up to date in real time with out over loading the processor and causing it to crash The web server will need to be able to handle requests from multiple users supplying up to date information with out causing any other components to lag and miss a read Getting all of our components to interface correctly with the microprocessor and communicate with each other in real time will rely heavily on efficiently implemented software that is robust and won t get hung up when many peripherals are active Dynamic C is currently the language of choice to develop software on the RCM3315 and has not currently lead to any unexplained issues 2 0 Software Design Considerations The design considerations that are guiding the software development of the project are mainly focused on which external devices need to be real time interrupt driven and time driven Since we are using an RCM3315 and Dynamic C handles all memory allocation management and there is 512K of SRAM 512K of Flash and 4MB of Serial Flash memory usage was not a major design consideration The application code will be organized using a hybrid between polling interrupts and timing Both the rfid and bill acceptor modules will be called in a polling fashion They will both be placed in the main loop and when the function is called it will check if data is available Upon receiving data the rest of the routine will run and perform its function The temp
12. rature probes and run compressor as needed Check RFID Digital Systems Senior Design Project Spring 2006 RFID Y biet Output user data Scanned biometrics to lod screen N ek z RPG ISR Determine if Add Credits to rotated or user aocount and pressed update Icd screen Update LCD and assert selection Check Server Staus Flow Meter ISR Call appropriate cgi or static page loaded Determine which flow meter caused the interrupt and increment its counter ECE 477 Appendix B Hierarchical Block Diagram of Code Organization Digital Svstems Senior Design Project init http handier validator cgi ces addcredits _data adduser Spring 2006 main temp_probe rf_id bac readbyte sendbyte Icd readbit sendbit Comptags verify_user login Ied bio 10
13. represents the sign of the data 1 being negative and 0 being positive The temperature can easily be converted by right shifting the first byte and adding 5 if bit 0 is a 1 If the temperature is found to be higher than the upper bound of the temperature range and the compressor is not already running a signal will be sent to the actuator through a port pin to activate the compressor Likewise if the compressor is running and the temperature is lower than the lower bound of the temperature range the compressor will be shut off This module is currently functional as a stand alone routine bac The bac function will be called in the main while loop every few minutes The time between callings of the function is not yet known but frequent calls are not necessary for its purpose The purpose of this function is to go through each active user and update there BAC This value will be calculated and updated using the user s weight the amount they have drank during the current session and the period of time in which they have been drinking If a user s BAC becomes higher than the set limit 08 the bac function will set a flag for the user indicating that when they are logged in the tap will be locked by the solenoids This function has not yet been implemented but pseudo code has been created for it http handler This function is a routine provided by Dynamic C that handles all requests to the embedded web server Only initialization
14. s and cgi functions needed to be coded for the server to work The ip address dns gateway and netmask values have to be added to tcp_config lib for the server to work properly Web pages and cgi functions to be used have to be inserted into a resource table with their corresponding handle so http_handler can route requests to the proper place 3 Web pages are loaded into memory using the ximport command and a handle is associated with the file CGI functions are created for pages that display dynamic data and a parsing function was taken from the post c sample program that came with Dynamic C Parse_post can be called by a cgi function to extract data entered by a user into aform This is necessary for obtaining new user information as well as keg information Several cgi functions will be used to display user statistics keg statistics and system diagnostics The cgi functions simply write actual lines of http syntax into a buffer that gets translated into a web page Also a login feature will be added to the server so that only appropriate users can modify and add user accounts An authorized user will have access to submit a user form to add new users as well as kegs into the system They will also be able to ECE 477 Digital Svstems Senior Design Project Spring 2006 modifv temperature levels for the kegs A basic webserver has been implemented that will produce a basic user statistics page displaving dummv variables in the routine a basic svs
15. tem diagnostics page that displays dummy variables and a login form that will accept the data entered and compare it to a predefined user name and password If the password checks out the cgi produces a page that says login successful and login failed if the password was incorrect rpg The rpg0 function will be interrupt driven and called each time the rpg is turned or pressed The purpose of this function is to determine what kind of action was applied to the rpg and make appropriate changes to the Icd screen The rpg can either be rotated left or right or pressed It will be used to navigate through menus and make selections as needed flowmeters The flowmeters function is interrupt driven An ISR is called each time one of the flow meters has a reading Each flow meter is attached to the interrupt pin and to an input pin designated for each flow meter When an interrupt is detected the flowmeters function detects which flow meter caused the interrupt by comparing the previous value of the flow meter s pin to the current value The corresponding keg is then decremented by I ml and the user s alcohol consumption is incremented 4 0 Summary This report presented the complex problem of developing a software application that will effectively and efficiently bring all of the external components together with an RCM3315 The details of this report lay out a detailed map to show how this problem is to be solved The issue of real
16. time operation has been addressed and by using a polling interrupt timer based layout to implement our main function true real time operation should be successful Many of the small components of the development have been implemented such as hardware integration routines that perform small functions and give a strong basis on which to begin developing the more complex main program By combining these already implemented modules the development of the main application should be smooth and merely need to address real time issues that arise from too much interaction between the devices and the RCM3315 ECE 477 Digital Svstems Senior Design Project Spring 2006 List of References 1 2 3 4 Rabbit 3000 Microprocessor User s Manual http www rabbitsemiconductor com documentation docs manuals Rabbit3000 UsersManu al index htm Rabbit 3000 Microprocessor Designer s Handbook http www rabbitsemiconductor com documentation docs manuals Rabbit3000 DesignersH andbook index htm Dynamic C Function Reference Manual http www rabbitsemiconductor com documentation docs manuals DC DCUserManual ind ex htm Dynamic C User s Manual http www rabbitsemiconductor com documentation docs manuals DC DCUserManual ind ex htm ECE 477 Appendix A Flowchart Initialize serial ports and i o pins 60 seconds Update BAC for each user and block illegal users Check tempe
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