Re: Debugger board for P4 ECMs

[Ludis Langens <ludis@cruzers.com>]

steve ravet <sravet@arm.com> wrote:
>
> You're saying you can single step, dump mem, etc. from
> a PC/MAC?

mswayze@truswood.com (Mike Swayze) wrote:
>
> what exactly does a debugger board allow one to do with an ECM?

"nacelp" <nacelp@bright.net> wrote:
>
> Can some one step up and clearify what a debug is?

I can dump and alter memory, I/O, and registers including the PC.  I can
also run simple programs written in an interpreted language.  There's
currently no disassembler because all code in the ECM is part of the
debugger.  It's easy enough to work from a listing instead.  Plus, a
desktop system could do a much better job of disassembling.  There's
also no single step because the P4/HC11 doesn't support that in
hardware.  There are tricks to single stepping on such systems.  I now
know enough about the P4 hardware to try one.

The timer chip on the board is useful for simulating EST, MAF, VSS, and
VATS signals.  Because it uses the same clock as everything in the ECM,
any ECM timer values will be rock solid steady.

This board could be used on an ECM running an engine.  You'd get a
serial interface to a laptop separate from the ALDL interface.  This
would require grafting debugger software onto GM's software.


steve ravet <sravet@arm.com> wrote:
>
> What software are you using?

On which end of the serial connection?  On the desktop end, a dumb
terminal emulator is all that is needed.  You could even use an ancient
teletype.  On the ECM end, I wrote all the software.


"Peter Fenske" <Peter_Fenske@bcit.ca> wrote:
>
> Do we have pcb layout yet..? do you need help with this?

Richard Wakeling <kojab@zxmail.com> wrote:
>
> This is of course going to be applicable to the
> aussie 808. Very interesting. Ludis have you designed a PCB yet?

Steve Ciciora <ciciora@edison.chisp.net> wrote:
>
> If no one else steps up to the plate, I'll lay out a PCB, work up
> estimates for PCBs, etc.  I won't be able to test it,
> or get board dimentions.  If someone is willing to help me with the size,
> I'll start laying out a PCB.

I've wire wrapped one on a 1.3 by 5.6 inch perf board.  This board sits
at a right angle to the ECM's PCB.  This size is just right for the
'165.  The ECM's case holds the board tight enough to keep the wire wrap
pins from touching the case, even though some pins are less than 0.040"
from the board edges.

I've been using this board recently and have found that I could use
several more - one for each type of ECM on my bench.  It would be great
if someone designed a PCB leading to a group purchase.  I of course have
a component layout for the RS422 version.  I've thought about how to
change it for an RS232 port.  It'll be a tight fit.


Steve Ciciora <ciciora@edison.chisp.net> wrote:
>
> I don't have a 1227165,

"nacelp" <nacelp@bright.net> wrote:
>
> I got a working 165 that I can loan you.

This board works with more than just the '165.  It'll also work on a
'730, '727, '748, '749, '8253, and so on.  The only thing special about
the '165 is that it fits inside the case.  The other ECMs require
cutting a large hole in a side of the case and having the board stick
out.  Or just run the ECM without a case.


In case it isn't obvious, there is no EPROM on this board.  The software
to use it needs to be programmed into a MEMCAL (MEMPAK for the '748).

-- 
Ludis Langens                               ludis (at) cruzers (dot) com
Mac, Fiero, & engine controller goodies:  http://www.cruzers.com/~ludis/

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