ECU numbers on GM

[Ludis Langens]

Scott Schaaf <SSchaaf at ERINet.com> wrote:
>GOOD LUCK!!!   It APPEARS to be 68HC11,,, BUTTT,  the pinouts DO NOT
>mach that of any HC11.  Nor do any of the other 54 pin chips.   I have
>been trying DESPARATLY to find out about these ECMs, and to no avail. 
>If you get lucky, PLEASE let me know. 

Don't expect to find a "real" HC11 in the ECM.  I've taken a very quick look
at a P4 class ECM.  It has three large chips which appear to be 1) a custom
CPU-core-only 68HC11, 2) a custom I/O and RAM chip, and 3) a custom timer
chip similar to a 68332's TPU.  There is also a medium size chip that is the
custom limp-home mode controller.  One of the smaller chips is likely a SPI
interfaced A to D converter.  And it wouldn't surprise me if there is also a
SPI PIO chip.

If you are looking at an older C3 class ECM, there will be a custom CPU-core-
only 6801, one or two custom ROM/RAM/PIO combo chips, a custom timer chip, a
custom A to D chip, the custom limp-home chip, and a custom [are you getting
the picture yet?] oscillator & clock generator chip.  Plus, a custom IAC driver
chip, a custom ignition module interface chip, a custom power supply chip, and
a semi-custom O2 sensor amplifier.

It is safe to say that you won't find info on any of these custom chips in a
Motorola data book.

                   unsigned long BinToBCD(unsigned long i) {unsigned long t;
Ludis Langens         return i ? (t = BinToBCD(i >> 1), (t << 1) + (i & 1) + 
ludis at netcom.com                 (t + 858993459 >> 2 & 572662306) * 3) : 0;}