pcmhacking.net

Hi all, I am getting started on disassembling the bin from my 1997 Barina 1.4. Yes, I can hear the laughter from here but it will be interesting to see how much of a common code base is in use between Europe and the rest of GM.

I have made a start with IDAPro on the BFZN bin which is also for the same engine until my EPROM burner arrives.

What I was looking for is some commented disassembly to assist in understanding what is going on, with a focus on the serial routines so that I can work out how to talk to the bugger. I have managed to locate a number of maps but have not yet fathomed out how they are processed. Understanding the IO port allocations is also on the hit list for deciphering the code.

Any assistance would be greatly appreciated. I plan to post the final result on this forum.

Simon

I think it'll be motorola 68k, possibly similar to this (via diy-efi for an american pcm of the same vintage)

antus wrote:I think it'll be motorola 68k, possibly similar to this (via diy-efi for an american pcm of the same vintage)

Thanks antus but it is definitely 68hc11f1 going by the rom mask id, and the code disassembles fine with the hc11 in IDAPro. Thanks for the file - I will have a look at the attached code for educational purposes.

If it suits you, I can keep any code confidential.

Simon

I dont use IDA, but if you post the BFZN bin will disassemble it using M6811dis and post it here. Can likely add some comments too.

VL400 wrote:I dont use IDA, but if you post the BFZN bin will disassemble it using M6811dis and post it here. Can likely add some comments too.

The comments would be extremely welcome. Do you want just the bin or also a copy of my disassembly as well? I have managed to find the vectored jump tables, some calibration tables and have commented some of the IO and ADC read routines. There seems to be quite a bit in common with some code that I have seen. I will post them in the morning as I am on the ipad now.

Thanks.
Simon

Can post whatever you have so far.

VL400, here is the bin. It is a 27C256 in a small blue memcal carrier. Here is the ASM - I have tried to define some maps but am quite sure that I have made a mess. Do the maps have a 3 byte header? Thanks again.
Simon

A lot of tables have a 3 byte header for X start value, Y start value and 3rd byte for number of rows in the table. The x and y values are then normally multiplied by a constant, for RPM as an example it is normally 25.

You might be able to find some of the common functions here. Specifically those like P4LKUPQ.

http://www.diy-efi.org/gmecm/papers/anht_hac.pdf

There are also a heap of disassemblies here:
http://pcmhacking.net/forums/viewforum. ... 6&start=25