Mode 4 Serial Data and stuff.....

[Scot Sealander]

Ross Myers wrote:
 
> In Mode4 serial data comms (Controller Mode) where the user can change > AFR, SPARK etc, what would be some valid commands here?.

Depends on what you are talking to.  You really need to look at
the code and see what the sent data will do.


> Secondly, Paul Blackmore came up with a good idea on reading protected
> Memcals, just dump out the program on the ALDL line,

Doesn't work, at least on some I tried.  Tried to read a friends '95
Olds SFI 3.1L.  It dumped RAM ok, but the code must of had address
blockers on it.  Some of it came out, but the data started repeating
itself.


> however a Mode2 dump is only good for 64bytes at a time, makes for a 
> VERY long task if it's a 512K

What is very long?  I wrote some Mode2 dump code, and it dumps a 32kx8
EPROM out the ALDL is just under 50 seconds, using a 10Mhz 286 laptop.  
It uses the 64 byte ALDL checksum to make sure all the reads are good. 
I don't think that is slow.


> And finally, can anybody confirm that GM seems to stick to a standard > I.D for any 'box' on the Line, ie. a PCM = $F4, ABS = $F9 etc.

The ECM ID can vary.  Sometimes F4, sometimes F0.  There are others too.

Scot Sealander