intro, hyper7148

[Tom Hussey]

Mike Pitts wrote:

> The P4 however does not require a DirectScan type of tool because
> the P4 has a "memory read" serial command that allows you to read
> any location in the 64k memory space, including registers and such.
> At 8192 baud, the speed has been sufficient for my purposes.  I've
> adapted the code in the eprom to accept a custom "memory write"
> command of my own design so that I can write to RAM and to EEPROM.
> I've even protected the routines from race-conditions. 
In my work on my '97 I have found the direct read as well and used it to
dump the memory space. In my case however, the Flash used is 512K and is
bank switched. The memory read can not get to the second bank and many
of the other modes for OBD 1 are gone in this later code. I am working
on download through the OBDII (J1850) port now. Code is huge however. I
have more than 8K of commented disassembly for DTCs and freeze data now.
> 
> BTW: I have a friend who cooked his DirectScan by plugging the
> card edge connector upside-down (it's not keyed).  He's lucky he
> didn't cook his ECM, although they are plentiful and cheap in
> the local boneyards. 8-)
> 
> -Mike