It's not my code here it is again: Alltrax AXE/DCX serial communications protocol.
The following notes are excerpts from the source code for the controller. The controller is a slave, it only speaks if spoken to, and only then if it understands the command, checksum is correct and so on. You'll have to poll the controllers RAM for data. You can write memory locations in flash and eeprom, but all it will do is cause us both headaches. I've identified the commands in this protocol so you don't have to tinker around trying to find them, but do us both a favour and leave flash/eeprom alone. Call Alltrax for support. Serial protocol is RS-232, 9600 baud, 8 data bits, no parity, 1 stop bit, no handshaking. Protocol only uses a source/target I.D. and checksum to validate incoming information, it wasn't meant to live on a network. The controller understands 6 commands, as detailed below, but really all you should be doing is reading RAM. The target processor in the AXE line is a PIC16F873, in the DCX it is a PIC16F876. AXE communications Spec. All references relative to motor controller. ;Communications Packet Protocol ; ; Recieve Packet Format ; ; Name Size Definition ; ; source/target 1 byte Windows App is 5h, controller is Bh ; command 1 byte command function to controller ; data1 1 byte ; data2 1 byte ; data3 1 byte ; data4 1 byte ; checksum 1 byte OVERFLOWED SUM OF PREVIOUS SIX BYTES ; ; ; ;Command byte definition ; ; This is the instruction set for communicating with the controller. ; 00h = read byte of program (flash) memory ; 01h = write byte of program (flash) memory ; 02h = read byte of EEPROM memory ; 03h = write byte of EEPROM ; 04h = read 3 sequential bytes of RAM ; 05h = reset ; ; 04h = READ RAM - This command fetches three sequential bytes of information ; from RAM (variable) memory and sends it to the Windows host. ; variable locations are organized in order to minimize ; the number of read cycles needed to refresh data. ; ; Read RAM Packet Format (sent by PC) ; ; source/target : 5Bh (windows app is host, controller is target) ; command : 04h (read three RAM bytes) ; data1 : ADDRESS, in hex. ; data2 : DON'T CARE ; data3 : DON'T CARE ; data4 : DON'T CARE ; checksum : OVERFLOWED SUM OF PREVIOUS SIX BYTES ; ; After decoding the packet, the controller shall assemble the following ; information and reply to the Windows Host: ; ; Response Format (sent by controller) ; ; source/target : B5h ; command : 04h ; data1 : ADDRESS (start address of three sequential bytes) ; data2 : data @ ADDRESS ; data3 : data @ ADDRESS + 1 ; data4 : data @ ADDRESS + 2 ; checksum : overflowed sum of 6 previous bytes ; ; ; ; ; 05h = RESET: This command causes the program to goto the START location and begin anew. The complete 7 byte protocol must be sent, but all data is dummy. The following are RAM locations you can read to get measurement data. High and low bytes are in successive locations, thus you can fetch both high/low byte with one read cycle. THROT_POS EQU 0x20 ;8 bit Throttle position, 00h = off, FFh = wide open DIODE_TEMP_L EQU 0x2C DIODE_TEMP_H EQU 0x2D ;Internal Controller temperature, ; BATT_VOLT_L EQU 0x39 ; 0.1025 volts per bit. BATT_VOLT_H EQU 0x3A SHUTDOWN EQU 0x3B ;Error status, any bit set, NO PWM output. OUTPUT_CURR_L EQU 0x60 ; IOUT = 1A/BIT, 0 - 1023A OUTPUT_CURR_H EQU 0x61 ; high byte Battery current may be calculated as a percentage of output current, assuming continuous motor currrent. Convert THROT_POS to decimal, then Ibattery = (THROT_POS / 256) * OUTPUT_CURR_H,L Temperature is measured with a Kelvin sensor, temp = 2.73V @ 0C Thus there is an offset at 0C = 559 counts. Temperature slope = 2.048 counts / deg C (positive tempco.) >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 2008/2/29, john fisher <[EMAIL PROTECTED]>: > > I'd like to suggest you use the sourceforge site to post your code. For > one thing unknown others will look for it there, > for another sourceforge provides easy-to-use maintenance tools such as CVS > and Bugzilla, now including stubs to > commercial implementations that can bring in some cash. Other developers > can join and improve or extend the code base. > > A project quickly becomes useless without maintenance, and bug tools. > > I like the principle of using cheap used ebay parts. There are a lot of > new tiny linux based pcs, but WTH if the Palm is > good enough, why re-invent the wheel? > > Thats my opinion, its up to you. > > > > John > > >
