pcmhacking.net

Has anyone discovered the JATG or BDM ports on any of the ECM's? This would provide the easiest way to background debug a PCM/ECM.

Where I work we use JTAG to flash the early proto products, and then when we get the software into our flash tool, then we use that. But one of the first things we make is the JTAG interface so we can flash and so software group can start to work on writing software code.

I have some old debuggers, like a few wigglers and some others that are similar. This lets me plug into a parallel port and if I had a place to connect to the PCM/ECM, would be able to get on the back side and be able to flash or send any commands needed, direct. Even datalog, it would be super fast too....

Looked at a INCA tool once, seems that is probably just that, JTAG or BDM.

i dont think the ecus or pcms used by GM have jtag or bdm, being based on an older hc11 architecture the flash based pcms use a proprietry software method to load a bootloader ram after a security key challenge and then jump to it. but i have not done that myself, as im still looking at the older ones...

I have been looking at this for the later flash pcm's for the Holden. I see they have two rows of BDM contacts unlike the LS1's three rows. The flash eeprom is am29f010b-120je PLCC 32 and is positioned quite close to the BDM contacts. I can trace the lines back to the eeprom and currently think that this would be an option so that I can dump the calibration from them prior to taking the eeprom off the PCB. I want to make up a header for emulation and I don't think it will be that hard. If I cut the legs off the eeprom close to the eeprom case it will leave the legs attached to the PCB and give me something to work with. I was thinking that if I made up a simple PCB to solder down onto the legs, then I could reroute the track lines to a socket for a Ostrich to plug into.

Giving away all my secrets here....

I personally have not used a BDM and would like to know more about the required hardware and software to get the job done.

Any chance you could give me a run down as I would like to have a crack at it.

Cheers

Mick

There are some HC11 in-circuit emulators around but GM have not used an off the shelf HC11 - although from VR Auto PCM and later they are close. So something like that *may* be able to be used.

The '808 style ECM has the edge connector near the memcal and the later flash based PCMs have the two row header near the flash chip (if its the same one your talking about Mick, you can add an NVRAM/EPROM/Ostrich to the two row header and remove the current flash chip) for access to the data bus. For everything in between I'd say youd be plugging something in using the memcal socket only.

While its not strictly JTAG or BDM hardware thats used it prob is possible to debug it, depends how deep your pockets are too.

Yeah that's the one I was thinking of. I have a couple of these PCM's to play with and I was having a look at one today. Would be great if you could hook straight up to the BDM contacts on J4 side of things. Following the track lines on these is no easy task for my old eyes. Might have to get some light going, this is one of the reasons why I was going to use the eeprom pins, would save me the time as well tacking them down. Interestingly enough there are another 8 or so contacts with J3 enscriped on the PCB on an edge at 90 degress to the 2 rows. When I checked those track lines out they sort of just went to dead ends by the looks. As I just purchased a 2002 VY V6 for the misses to drive, one way or another I'm going to get a emulator in this thing. The $06 XDF and ADX is coming along just fine with some help from friends. Thanks Lads!!

Might see if I can get the PLCC 32 off the board without hurting the PCB and get a read on it. Might have a look and see if I can get a socket on it at least so I can have a play and test a few things out.

Have some Sniff hardware and software as well, have not got it out of the breakout box yet but I'm thinking about it.

Hummmm, Lots of fun to be had lads.

Mick

As for JTAG/BDM hardware, I have some http://www.macraigor.com/wiggler.htmWigglers laying around. We use them at work and people just toss them all too often. I rescue when I can!