Misc 101 Information

[Ludis Langens]

Bruce Plecan <nacelp at bright.net> wrote:
>
> > what processor is run in the thing?
>
> The 1227747 is in the C-3 generation of gm ecm's which all use,
> a Motorola 6809 type of device, and the newer P-4's use a 68HC11
> type.  The "type" is that, it is to gm specs, and there are small
> differences from a ecm processor to a off the self device, as I
> understand things.

Not a 6809!  In it's day, the 6809 was a far too high end processor to
show up in an engine controller.  (The 6809 is partially source code
compatible with the 6800/6801/68HC11, but not object code compatible.)

The C3's use something like a 6801.  A real 6801 is a 6800 with some
extra instructions, ROM, RAM, and IO all in a 40 pin DIP.  GM's chip is
just the 6801 CPU core in a 40 pin DIP using a pinout very similar to a
6800 CPU.

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