747 Rom Emulator / design

[Steven Ciciora]

I volunteered to lay out a board.  On this board, though, I would like it
super-simple to read the existing prom, so even the novice can upload
their bin to the bin archive (if a copy isn't there already).  What do
people think about using that expansion edge connector?  It's usually
covered with a clear type of paint.  Anyone try removing it?

I like the idea of dual port ram, but has anyone actually used it in a
product?  My main concern is it really available today, and will a bunch
be available two months from now?

Also, someone mentioned making an adaptor pcb to adapt from 0.4" wide 24
pin socket to a more standard 0.6" wide ZIF socket.  If I make a board for
the above emulator, I'll make one of these boards too.  I'll have to
measure my 7747 to see if it will fit (without the zif, just a normal
machine socket).

- Steven Ciciora


<snip>

> 
> As far as DP ram, IDT makes them and they're really no more complicated
> than SRAM.  There are two address busses, two data busses, one of each
> to the EPROM socket and PIC.  As I recall there weren't any contention
> issues to worry about as far as accessing the same address from both
> ports since th ECM only reads, never writes.  go to IDTs WWW page and
> search for IDT7008
> 
> --steve

<snip>

----------------------------------------------------------------------------
To unsubscribe from gmecm, send "unsubscribe gmecm" (without the quotes)
in the body of a message (not the subject) to majordomo at lists.diy-efi.org