Eprom Emulation

[Tom Sharpe]

David A. Cooley wrote:

> At 06:51 PM 4/6/99 -0500, you wrote:
> >Ludis touched on this previously, here's what he said about read timing:
> >
> >
> >-------------------
> >The P4's deselect the PROM for 120ns, but enable it for 360ns.  I don't
> >how much of the 360 is lost due to data setup time.  OTOH, the C3's
> >might not deselect the PROM at all between back to back accesses.  Which
> >brings up the point - it might be good to prevent a bank switch between
> >data read cycles of a "LDD $89AB".
> >-------------------
>
> Didn't catch this the first time it came through...
> A couple things from personal experience with the C3 and P4...
> On my Buick GN I made a board that had 2 proms on it and used a 4066 to
> switch the CE line so you could select whichever chip's cal you wanted...
> I used to use it constantly, switching back and forth under cruise, idle
> and even a couple times at WOT.
> There was never a hiccup.
>
> I also had a 93 Jimmy withthe 200HP Vortec 4.3L V6 and a P4 pcm...
> I had a 6 in 1 JET chip... it was basically a 27010 chip with 6 programs
> burned into it (top 256K was empty).  The lower address lines went to where
> the stock address lines did, and the data lines all went to the PCM.  to
> switch programs, all you did was toggle one of the 3 higher address lines
> to select the 128K bit block you wanted...  How about an Emulator that
> follows similar lines?

Let's use an EEProm - draw the circuits  Tom