Reading RAM locations

[Roger Heflin]

Well, with a PC card with enough I/O connectors (address+
data bus, maybe 24-32 or more) you could wire each I/O connection
to each address line, and to each data line and read out everything.  There
would also probably need to be some status lines that were connected
to give you some idea what was going on the bus.  When I was in college
we messed with a bus snooper, and the one we had knew what was code and
what was data and would disassembly the code and put it on the screen.
Probably given the type of chips we are using, you may also need some
I/O lines to connect to the port outputs.  Really all the connections
that you need hooked up, could come straight off the microprocessor,
I believe that was how the ones I used worked, since there is really
nothing going on that hte micro does not know about.

			Roger Heflin
			EE in a past life

On Mon, 14 Sep 1998, Mike Pitts wrote:	

> 
> Has anyone seen: http://www.chuengineering.com/
> 
> It's a device which plugs onto the diagnostic card egde on the 
> C3 ECM and allows a connected PC to "see" RAM (and probably 
> ROM locations) at any time upon request.
> 
> I've just sent them an email asking if they can make one for a P4, 
> but assuming the answer is "no"...does anyone here know how 
> to make such a device?
> 
> I don't want to change PCM RAM locations, but rather just spy 
> on them while the engine is running.
> 
> TIA,
> -Mike
> ==========================================
> Mike Pitts
> Delray Beach, FL
> mpitts at emi.net
> http://www.emi.net/~mpitts/mike.htm
> ==========================================
> 
> 
>