BDM anybody?

[Lynoise]

I have been reading up on the BDM (Background Debug Mode) which is available on the M68332. Most all who sell the interface mention that it can be used to read write to on-board flash devices (as well as an infinite number of other cool things).

Now I wouldnt imagine that GM has any of the pins on the OBDII connector go to the CPU for the use of BDM BUT. If this works its an option for flashing the memory.

There are many hurdles with BDM. The first is that you have to tell the CPU you want to start it. This is the main problem (after connecting the interface of course). There usually is a way to do this through hardware but who knows if GM implamented this or not. There are other ways (Im looking into them now).

I am going to buy an interface and a debugger to use with it and start playing as soon as I get confirmation it is possible to do on our chips.

Anyone out there have any exp. with BDM on the 68xxx(CPU32 core)? Any help/info would be great and m ight just get this board rolling ;D

[Keith@HPTuners]

It sounds very interesting. I've discussed this a few times with some local colleagues however we never really did anything about it.

I'd be very interested in what you find out.

Currently the adapter for my EMP-20 is down so I'm been kinda quiet lately.

[RoboGeek]

kinda makes you want to put on a connector with everything hooked up to the right stuff.

[Lynoise]

Anyone know which pins on the 68332 should go to the BDM header? schematic?
Thanks

[Lynoise]

OK this is what I have so far for the BDM header.... From about 100 PDFs on Motorola's site .

DS(1) _. ._ (2) BERR
GND(3) _. ._ (4) BKPT/DSCLK
GND(5) _. ._ (6) FREEZE
RESET(7) _. ._ (8 ) IFETCH/DSI
VDD(9) _. ._ (10) IPIPE/DSO

A question though.. There is no pin labeled for ground on the CPU. Are the 2 GND pins for BDM just the ground (case)? Also will any VDD on the CPU work? There are 13 pins on the CPU labeled as VDD.

For those of you who care.. some more info...
There are 2 versions of the 68332. There is a 144 pin package and a 132 pin package. These PCMs use the 132 pin. Pin 1 is aligned with the dot (as usual). The dot is in the middle of the top row of pins. It then counts to the left and around counterclockwise.

The pins in question for BDM are as follows:

BERR 70
Requests a bus error exception

BKPT/DSCLK 56
Hardware breakpoint input or background debug mode serial data clock input

FREEZE/QUOT 58
Indicates that the CPU32 has entered background debug mode or provides the quotient bit of the polynomial divider in test mode.

IPIPE/DSO 54
Instruction pipeline state output or background debug mode serial data output

IFETCH/DSI 55
Instruction pipeline state output or background debug mode serial data input.

DS/PE4 85
Indicates that an external device should place valid data on the bus during a read cycle, that valid data has been placed on the bus during a write cycle, or the pin is digital I/O port E4.

RESET 68
System reset

VSS Choice of 13 pins
Power

GND
Ground

Looking on the PCB I see where I can tap into most all of the needed pins. There is a problem with 2 though:
DS (pin 85) doesnt seem to go anywhere on the board. Also BERR (pin 70) doesnt seem to go anywhere.

I dont know much about the PCB used in the PCM but if it a multi layer (3+) then maybe these go to one of the middle layers? Although wouldnt it have to go to a solder point on the top layer to get to one of the middle layers. I would rather not try to solder right to the pin on the CPU

Ohh well moving forward.. slowly but moving..
I was really hoping that the needed connections would be available on the PCM plug somewhere. Any ideas on finding out if this is true or not.. Id rather not try to trace out the PCB.

[kojab]

Are we talking about the same OBDII PCM? I am sure I counted 160 pins on the processor. This Delphi site also confirmes 160 pins.
http://www.delphi.com/pdf/delcopdfs/ECMCurr.pdf

Are you sure yours is 132 pin?

Cheers All
Kojab.

[Lynoise]

Yep counted like 3 times per PCM (I have 2). Also in Motorolas Doc on the 68332 it shows the 132 pin config. having the dot in the middle at the top and thats how mine are.

http://www.lynoise.com/stuff/68332/a...332/c3over.pdf Page 4

The 160 that the delphi PDF is refering to is for the connector on the actual PCM. I count 160 there as well. The 132 is the number of pins on the actual CPU, the 68332 chip.

[RoboGeek]

Think I'll read up on this a bit tomorrow.. unless the sun actually comes out ;D

[Keith@HPTuners]

Very interesting..



I'm counting 132 as well.

[Lynoise]

Yep thats the one...

That PCM looks pretty funny... same processor but the layout of the PCB is very different. Mine are out of a 99 3.8 SC and 2000 3.8 NA. 97 was a funny year for PCMs I hear I guess they changed the design in 98 to the new style.

[Lynoise]

That board is missing somthing!!! isnt it :P

[Keith@HPTuners]

LOL, yea I didn't even notice the flash chip wasn't there.. hehe

Yea, 98+ have a different PCM. Much more compact design.

[RoboGeek]

your workbench is way too clean lol ;D

back to BDM.. did you by any chance save any of the links to the docs you were reading? Otherwise I'll go search..

All the stuff I found (not on motorola's site) seems to need alot of adaptation...
I have the background debugger but I have yet to figure it out.
here's some things I've been reading about it.. kinda cool..
I'll keep adding to it..

http://cmp.felk.cvut.cz/~pisa/m683xx/bdm_driver.html PDF version

http://www.kanis.de/home/products/sps_cpu1/i_sps1.htm

http://www.rtems.com/rtems/maillistA.../msg00193.html

http://www.pemicro.com/support_center/faq/faq.html

[Lynoise]

Is that a tech II I see to the right on your bench?
Nice!

[Keith@HPTuners]

yeup.

[Lynoise]

Well I bought a BDM interface. I was hoping to get it today but no such luck.. maybe tomorrow.

The docs I am using I dl'd from motorolas site. It was 1 honking zip file 70 or 80 megs. I unziped and made them available on my server.
http://www.lynoise.com/stuff/68332/auto/open.pdf
There is info on all Moto. chips used in autos.

[Guest]

Sorry guys received this a while back. :-[
Subject:
PCMs in 1999 Gen III
Date:
Sat, 12 Jun 1999 07:42:28 -0400
From:
"J. McDonald" <[email protected]>
Reply-To:
[email protected]
To:
"'[email protected]'" <[email protected]>




I'm fairly new at this, but here goes....

I have noticed that the same basic PCM is used for all of the 1999 GM "Gen
III" V8s (4.8, 5.3, 6.0 truck engines, Corvettes and F-bodies). The CPU
appears to be a 160-pin variant of the Motorolla 68332. Have I ID'd this
correctly? If so, is there a dissambler available? Why the extra pins?

Joe M

End of e-mail.

I have been looking at Motorolla's 160 pin package ever since then. Aparently never counting the pins for myself.
Ok onwards.
Would it be possible to make up some kind of socket which incorporated fine pins with points that could be placed nicely on top of the flash chip extracting its contents while it sits in place on its PCB and there by not removing it?

[Lynoise]

Thats exactly what Im trying to do here
Only time will tell if itll work or not.

Using the BDM (background debug mode) Motorola puts on the 68332 you can "break" into the curretnly running code and read/write registers/RAM/and Flash ;D

Hopefully the next few days Ill get my BDM interface and maybe get somewhere.

BTW the 160 pin is probably the MC68336/376UM chip.

[RoboGeek]

i have things that clamp over chips.. not for those specific things though..
Unfortunately the ones I have are for DIP chips and those only go to 16 pin. I'll bet they make them somewhere...

[Lynoise]

I finally recieved my BDM interface today. Going to try to make it work tonight. keep your fingers crossed for me. I would really rather not fry a PCM (although I have 3).