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To help keep the Flash Protocol thread on topic lets use this topic to discuss the actually cable we need to run our flash protocol code through.
Who do we have here that is an EE?
Who is interested in designing/building such a cable?
What hardware does the cable require?
What would we want out of the cable?
What would we need from the cable?
How do we go about staring this project?
I myself won't be of much help with the physical design of the cable but I can assist with the user interface.
I know of some people that have a converter working and they only need someone to write the firmware.. if the firmware where to be written it would all be done..
http://netdial.caribe.net/~highland/converter.jpg
This is from a working converter.
Well I'm not an EE I'm a software guy, but I've been researching this, and here's one possibility: an M68HC12B controller board, like this:
http://www.kevinro.com/documents/912b32/912b32.htm, with an MC33390 transceiver chip added (you need that to interface the microcontroller to the J1850 wires). Or you could use the newer gen controller, MC9S12DJ128. Either of those MCs includes a BDLC module, which takes care of the J1850/VPW protocol interface for you. Both have flash memory, although the HC12B only has 32K, and they can be used in single-chip mode meaning very few other components on the board.
Of course it's only so much hardware junk without knowing the protocol for reading/writing the PCM flash. And by the way the J2190 protocol does include read/write block modes, has anyone checked to see if they work?
Yes - they are what you need to use to read and reflash the PCM.Quote:
Originally Posted by oldgeek
Paul
i have acess to an EE who would be willing to help if we new what the cable had to do.
I have the schematics of a valid converter... Anyone care to help me with the firmware.. its all its left
I'm actually working on a full size PCI card (bigger is easier!)
Wont be able to get back to anything until after racing season ends
Had the power regulator and buffer circuits figured out but I lost them when I had to reformat - I knew I should have posted them here! lol
Anybody thats interested in helping with the cables go ahead and post here.. we can figure out the best way to proceed then
Was thinking about a Motorola 68HCS12 design. Not actually an EE, but have done some of the work toward it before deciding to take the CS path for profession.
Highlander:
What chip is that converter based on, and where could I get one? Would probably need that to start working on the firmware for it.
Tyrithe
Well, it has to convert signal... and send packets.. it also has to send block data packets which really don't follow the standard header format.. I'm not really sure though on this part, It still confuses me.
I think we can find a serial to vpw converter chip. I'm leaning towards a PIC type thing to act as buffer and possibly be programmed with some commands so there's no delay from the PC to the interface. PICBasic is pretty easy to program and theres serial port support already embedded. That would allow cable upgrades for future changes with just a downloadable file.
So we could really split this into 4 areas: VPW, PIC, physical (board,cables etc) and controller program.
Opinions? ;D
So who knows of potential cables that are coming out?
Chances are they will contain a Mot MC68HC58 chip.
I will have it with the firmware I believe.. price would be around 250 bucks for starts.
Has anyone designed a working cable yet?
I got distracted with something new and cool. Its basically a hard drive on a chip. I've been trying to load it with Real Time Linux and set up supporting hardware.
I just got a new job so now funds are available for me to buy parts. So I'll be starting up again shortly.
picbasic will not be powerful enough to handle this properly. To get the best performance you should really use a c compiler or you should suck it up and go ASM route. For simple projects, pic basic would work, but I wouldn't recommend it for this.
Quote:
Originally Posted by RoboGeek
Hello
Anybody look at this :
http://www.csielectronics.com/saint/
I spoke with the designer before, and is a REALLY sharp cookie. He has worked for GM in designing the "Tech2". this is a couple years ago but I remember asking if I could read/write/modify with this interface, and he said something like : "of course if you know how" I then pressed him for more info and he politly replyed he won't tell me a thing and that I should contact GM. :banghead:
But maybe you guys that can talk the talk and walk the walk, insted of me being a grease monkey that asked way too basic questions :-[
I do not know what his board has that is any more special then other interfaces but if someone could explain it It would be moocho app.
Joe
looks pretty sweet..
I'll send an email to Scott and see if he would be interested in answering some questions for us here...
How much for this system?
GM is moving to CAN pretty soon and im not sure if the new 05 corvette is CAN or j1850 (i hope its not CAN)
Anyways...
Anything done with the converter for obdii?
Well, I'm currently building an electronics interface for VPW to PC serial (RS232). I've got a phillips AU5783 VPW transceiver chip, put a PIC microcontroller in the middle and a MAX232 serial driver chip for PC serial comms.Quote:
Originally Posted by mike
(I've still got to program the PIC chip for VPW - RS232 communication). Very simple circuitry and low cost.
Anyone else gone down this path or Comments?