Question for the Gurus

[chri0029]

Okay, I was just looking back at my old JTAG notes and it's going to be more difficult than I thought (probably a little over my head). First I connected through a serial or parallel port before. I don't have those anymore and USB is a different animal. Secondly, I used a simple JTAG software program specifically for that application. I am not a programmer, so I don't think I could write one for this specific application. However, the chip data I posted a couple treads ago has some really good info and doesn't seem too difficult. It says the chip actually already contains an embedded erase and program algorithm built into it. That's probably what the board does anyway to enable the chip upon Tech2 program/ reflash command. Again, over my head but probably simple for the gurus. Any thoughts, let me know.

[chri0029]

That's what I'm thinking. I have JTAG'd an old IC years ago (read, erased, and reflashed), but never in this type of application. Truthfully, it's been so long ago that I don't remember much on how to do it, but I will have to read-up on my old notes. It only involves a few pins, so I would think that wouldn't be terribly difficult to solder or hot glue a few wires to the IC board since this is a spare PCM from a junkyard anyway.

[motohead_1]

If you thinking about reading whats on a chip maybe you can just jtag it. I dont know if it will read whats going on while its going on but if its static I'm sure it will read the e-prom.

[chri0029]

My '04 LA1 PCM had an AMD AM29F400BB-70SE chip in it. Attached is the AMD specs for this chip. I am not a CE, programmer, or hacker, but I would think someone could use this information to get the job done (or closer to the goal).

[robertisaar]

damn... GM went nuts on that compared to 1.5...

1-5, 9 and possibly 8 are completely skipped. i think it dumps it all at once.

[Weatheralls Auto]

This is the lastest info I have found (maybe some have different definitions of bootloaders? )

1) you unlock the PCM
2) set the PCM into diagnostics mode
3) request upload (to ram)
4) upload the "bootloader" after uploading you send the address in ram that you uploaded it to, this tells the PCM to reboot and start execution at that address
5) PCM reboots
6) the bootloader is listening fir commands
7) you tell the bootloader "give be bytes 1-256 of the flash" it reads them and sends you a message with the bytes in it
repeat 7 untill you have read the entire flash
9) turning the key off ... Wait 5-15 seconds... Turn key on and the ram is cleared and the pc reboots again.
Writing to the flash is about the Sam but the loader listens for write commands.

The hardest part is writing the bootloaders. They must be compiled to run on the motorolla 68332 chip. have yet to find a compiler for that chip

[robertisaar]

That's it, pick your punishment!

followed up with from the mod staff or from you to the mod staff.

i think the is less life-scarring than the ...

planethax: i'm not surprised that GM uses the same FLASH chips over and over, since it costs money to re-engineer for different chips. the CPU is likely identical as well.

[Weatheralls Auto]

Ya, I wanted to Test Drive IDA, way over my head ATM but learning lol.

Well I opened up 2 Pcms last night
This is what I found

Flash Chips
2001 Impala 3400

Intel
16236995
AB28F400BX
E5012
U8390438Q

1999 Chev Venture 3400

Intel
16236995
AB28F400BX
H3311
U0490294Y

Not sure of the differences between the Two besides last to lines, but def same family (maybe build code dates etc?)

It seems MANY MANY GM Pcms use this chip (even back to 96 4.3l in trucks I have seen)

Searching for Data on this chip, I come up to referrences to
AB28F400BX with a T90 or B90 at the end? not sure what that would be?

Also have found
http://pdf1.alldatasheet.com/datashe...400BX-B90.html
which seems to reference both B and T

Here is the image of the 99 Venture

[sprucegagt]

that, no...

the discusion about how to obtain IDAPro for no money.....

That's it, pick your punishment!

followed up with from the mod staff or from you to the mod staff.

[robertisaar]

That isn't illegal is it? I dunno why a mod (ha, we have mods?) cares what you are talking about unless its illegal in some way.

that, no...

the discusion about how to obtain IDAPro for no money.....

[SappySE107]

That isn't illegal is it? I dunno why a mod (ha, we have mods?) cares what you are talking about unless its illegal in some way.

[robertisaar]

Huh? What are you up to?

from what i can tell, making a free alternative to HPT/DHP...

[SappySE107]

Huh? What are you up to?

[robertisaar]

if you see this anywhere in the URL, it's a working one...

5235650

i probably can't say much more without mods telling me we're not supposed to do that...

[Weatheralls Auto]

Or a little DEMON smiley ?