EPROM Emulator Proposal

[thergen at svn.net]

I think it's a good proposal.  I'd like to suggest that a pushbutton
switch be part of the design that can be used to reload the default dpram
bank from the eprom (assuming it's present) so that you can recover from a
corrupted ram image without using a laptop computer.  Power-up/power-down
need special attention (as you already know) to avoid corrupting the ram. 
Maxim (www.maxim-ic.com) and others make parts with voltage supervisors
specifically for memory protection (let me know if you want specifics). 
 
Tom
 
On Wed, 7 Apr 1999, Ludis Langens wrote:
 
> The EPROM emulator debate on this list seems to be going in circles.
> Either people have short memories, or there are a lot of new members who
> missed the discussion and decisions made in the first few weeks of
> gmecm.  Either way, please read through the archives.
>
> Anyway, here is an emulator proposal based on the prior discussion.  I 
> did some ruthless cutting of features and expandability (indicated with
> a *).  I propose the use of a single dual-port SRAM (from Cypress or  
> IDT) and a 40/44 pin PIC microcontroller to load this RAM.  A battery 
> back up will keep the SRAM alive.  This allows an ECM to boot from the
> DPRAM immediately upon power-up.  The whole emulator circuit board  
> should be small enough to fit inside a '165/'727/'730/'749/'808 ECM.
....