EPROM emulator

[Andrew K. Mattei]

steve ravet wrote:
> 
> Maybe I'm missing something here...  What I thought we were talking
> about was a box with a flash and an SRAM.  You could download a PROM
> image to the RAM while the engine is running, and also dump the image to
> the flash.  The flash can probably hold several PROM images at once.
> Timing is such that none of this interferes with normal operation of the
> ECM.  Is that more or less the vision?

I think if you ask 10 engineers the same question, you'll get at least
11 different answers... <G>

Let's figure out the steps that we want to go through to accomplish our
goal. Our goal is to be able to change parameters of the EPROM image
while the motor/ECM is running. That would mean we want to have 1Mbit of
memory on "the left side" for the ECM to access, while we load a file
(up to 1Mbit) in to memory on "the right side" of the board. Then, after
our new image is loaded, we push a button on our little emulator board,
and the ECM switches programs. We can then make a new image on our
laptop, as we drive around the parking lot, make a tweak to the image we
just created, and when completed, we download it to the memory "on the
right side" (since we're now running off of the memory on the "left".

Personally, I lean towards making both memory banks EEPROMs - such as
the AM29F010. And using some buffers and the pic to control them. Do we
need additional circuitry for the serial to parallel conversion? ;) What
supplies the address lines to the "off line" bank of memory, so we can
write to it?

Just some thoughts... Random as they may seem... I realize that several
here already have designs in mind, but I work best by stealing others'
ideas and putting them through my own twisted improvements... ;)

-Andrew