I have a 1226864 TBI C3 computer in my 1991 bird 305. Been looking over the schematics and have decoded some info so far. I also have two pic 16f876 chips each with 22 io lines and 8k flash/256eprom/384 ram.

Memory address of chips on ECM

EPROM is @E000
U6 16023262 : TL532/ADC0829/MC14442 A/D @D000
U7 16023263 : Engine Control Unit @C000

The RAM/IO chip is probally a MC6846 chip, but have not been able to find any datasheets on it. But it has all 16 address lines going to it.

I'm planning on using the PIC Chip to emulate and read the original eprom. Once the eprom has been read into the pic chip it will have a cable that will plug into the eprom socket . Since this configuration will use almost all the io pins on the first pic chip, I plan on using a second chip to decode some of the additional address lines and run a LCD and serial port.

It would also be able to capture data by monitoring the address and R/W lines. The pic chip could programmed to switch table data values and apply algorithms to change the data mixture tables and timing.

Anyway step 1 is simple emulation of the eprom and the ability read the original prom. I will post some schematics in the next couple of days. I still need to study the ECM prom code some more.

 

I'm kinda confused as to why you're using a PIC chip to emulate the EPROM. Why not use a simple flash-rom chip..?

Have you seen the PROMinator..?

We are also working on a very simplified version of Lockers for high speed data reading. Is this what you're trying to achieve?

 

ken let me know when you get this working im definately interested. id also like pricing on the prominator pro and batch of the regular prominators. if you dont mind. i did a group buy on GM dis ecm conversion kits for the honda guys (86-89 accords)and i was trying to see if bulk buying was a good way to go ?

before anyone complains ive been appyling everything i leared doing this into a dual 4cylinder v8 dis DIY deal. keep an eye out.

ken73 im very interesetd toss me some mail at djfreggens@aol.com

 

Ken Pic chip can change data and substitute tables on the fly and yes it could capture data from the bus while the chip is accessing analog and io data. It would be nice to have a lcd display with a couple of buttons so that you can have a menu driven system to adjust parameters and display certain data points.

I need to know the 6801 processor crystal speed, anyone have a C3 opened up.

http://www.cruzers.com/~ludis/1226864sheet1.gif

I wonder if this schematic is accurate in reference to the eprom. What speed eproms are being used in these units. The schematic does not allow for any delays and whether or not the processor is read or write mode, of course as long as your only reading the eprom your ok, but if your code try's to right to it, you'll be putting data on the bus at the same time as the processor, could burn up something. I'm hoping for a single chip solution, but not sure if a 40mhz pic would be fast enough, it would have 10ns instruction cycle, so I can execute 10-20 instructions to get the data out there on the bus within 100-200ns. I could hook up a delay circuit if needed to strech the clock cycle on the 6800, simple slow device circuit and give me more room for playing. 10 instructions between a read prom interrupt does not give much leway for playing. By the way one PIC instruction takes 4 clock cycles. My other option is to use a dual ported ram chip, load it with the image when the processor comes up.

See 6800 datasheet for more info on the address and data timing.
http://www.eas.asu.edu/~cse438/refer...c6800_rev0.pdf

Thanks

 

Now you've REALLY confused me - are you talking about making a stand-alone unit akin to the Hypertech Power Programmer, or is this a system using a laptop?

 

I'm planning on adding the pic chip to act as a coprocessor. the 680x processor is running at 4mhz I believe and it does not look like even a 40mhz pic chip would be fast enough to emulate a eprom. So the dual ported ram chip should work well and allow me more flexibility with the pic processor for displaying data.

Yes a stand alone system. Evently it would be cool to just disable the 680x chip and us the pic chip to access the io & A/D chips.

Here's how I envision it.

Power comes up and the pic chip loads the code into the dual ported ram chip. The pic chip can disable the 680x by asserting a halt signal to the processor. The pic chip will have several buttons and lcd display to allow table changes on the fly.

I still have much to learn about the functionality of computer itself and fuel / air mixtures. Been reading and reading on this board.

The schematic of my 91 C3 puter is a little different than whats on Ludis's site. I picked up an extra puter to play with. Here's a pic of it. I have a tek 80mhz scope to look at signals with. I'm really interested in the diagnostic connector on the puter. could just interface directly with it. I understand theres a way to have the onboard computer to send out data to the co-computer. But am still learning about this. When I say the diagnostic connector I mean the one by the eprom, edge connector.

 

Talk to RBob.

 

Ok found a cop car C3 350 eprom disassembly here.

www.area51.org.il/~zaphodb/gmecm/8746hack.doc

All I need now is a rom dissembly to start working on my own code. Hint. I can disassemble it my self but I know someone else has already done it.

 

That is a full, ram, then eprom, then rom code all in order. I'm still having troubles assembling it because there is some format issue. BTW, that is my file somebody must have saved. I can tell because of the color and size of the title comment "START OF CODE" . Glad to see somebody has a backup for when www.diy-efi.org goes down.

 

Cool I did not look at the end of the code, just saw tables.

I've decided to butcher up my extra computer and cut off the io chips and a/d convertor and wire the pic chip directly to it. The pic chip has 8 a/d converters 10 bit and a bunch of i/o lines 33 all together should be more than enough to interface to the engine sensors and I will still use the existing circuitry for the inputs. After I cut off the chips with my dremel tool I will wire the pic input/outputs directly to them.

I'm going to get the processor from here
http://www.kronosrobotics.com/tuter.html

it has built in basic and can store 16k of code, probally plenty, but I can add a serial eprom if necessary to increase storage. 40mhz cpu and serial interface for programming. I already have a couple of LCD displays. Once I get the hardware and some sensors to play with it really won't take long to write the code. The same algorithium should be applicable to TPI also to some degree.

I bet some algorithums can replace some of the table data simplifing things even more. Remember these ecms are caveman stuff. Late 70's and early 80's.

 

Ordered the computer parts today.

Item 1
Product ID: DiosUltra (base computer)
Product Name: Dios Ultra Controller Board
Attributes: Kit, Male
Product Price: $49.95
Quantity: 1

Item 2
Product ID: MDR1 (injection drivers)
Product Name: TI SN754410 Solenoide and Motor Driver
Product Price: $3.95
Quantity: 2

Item 3n
Product ID: IC74HC165 Extra inputs
Product Name: 74HC165 Input Shift Register
Product Price: $1.00
Quantity: 2

Item 4
Product ID: IC74HC595 Extra outputs
Product Name: 8 bit Shift Register
Product Price: $2.00
Quantity: 2