P4 DELCO DATA-LINK

[steve ravet]

> HI & THANKS TO ALL WHO GAVE INFO & TO THOSE WHO WANTED MORE INFO ON
> JUST WHAT IT IS IM AFTER :
> 
> THE DELCO SYSTEM IS THE DELCO P4, IT HAS TWO CONNECTORS ON THE
> BOTTOM OF THE ECM AND IF YOU PULL THE COVER OF THE OTHER END YOULL
> FIND AN EDGE CONNECTOR AND A MEMCAL SOCKET (66 PINS). THIS SYSTEM
> USES A MAP, TPS, IAT, CTS, IAC, O2, SPEED, DFI/HEI, PROBLEY THE SAME
> AS WHAT YOU GUYS USE IN THE STATES.  IN AUSTRALIA WE RUN IT ON THE
> HOLDENS WITH THE BUICK V6, HOLDEN TPI V8, MPI 4CYL & TBI 4CYL (AND
> WHAT EVER ELSE I CAN SLAP ONE ONTO)
> 
> THE BAUD RATE FOR DATA IS 160
> TO GET THE ECM INTO DATA MODE A 10K RESISTOR IS PUT ACCROSS ALDL B &
> A AND DATA ID READ FORM E

AFAIK, C3 ECMs used the 160 baud rate, and P4 ECMs used the 8192 baud 
rate.  Someone else posted how to tell, the C3 processor is a DIP 
package and the P4 isn't.  Anyway, if you are trying to read the 160 
baud stream over a regular serial port you won't have much luck, but 
you will get a lot of framing errors :-)  Check the list archives 
for an article I posted (info that originally came from Dan Furgason, 
thanks Dan).  If you want to read the 160 baud stream, you'll have to 
connect the pin to a parallel port input pin, and watch it with 
accurate timing loops in software in order to extract the bits.