RE: FLASH ROM replacement

RE: FLASH ROM replacement

From: Bil Herd <>
Date: Sun, 3 May 2009 17:44:52 -0500
Message-ID: <>
My apologies for that, habit from the old days.

So I jumped in without really knowing the application or what the challenges
were, I assumed it was a "how to connect to something inside of something"
type problem if you were to replace an internal eprom with a reprogrammable
part and didn't want wires snaking out through the vent holes.

What kind of app is this targeting?  Cartridge, C64, or damm near anything?
Is it a matter of getting hold of the R/W line and the host can participate
in the reprogramming? 

Can the host be put into tristate reliably and something grab the buses, for
example a 24 bit shift register driven by 2/3 wire? (Let the programmer do
all of the magic byte stuff, the adapter just s/p translates).  Twice the
pins if you have to mux.

I assume that anything that adds price at all is out of the range, you'd be
looking a pin count for the address and data lines at a minimum price,
whether done with TTLish shift registers or PAL/PGA/uProc.

Too bad there isn't an AVR type with 512k flash. you think your talking to a
mem, your really talking to a proc.

-----Original Message-----
From: [] On
Behalf Of Jim Brain
Sent: Saturday, May 02, 2009 11:55 PM
Subject: Re: FLASH ROM replacement

top-posting is bad, but we'll save that lesson for later.

I wish they had such a thing, but alas, I've not found anything like it.

Still, while SoftROM is a similar idea (uC + SD/USB + RAM to simulate a
ROM), adding a uC and zigbee to this design would triple the cost or worse.

But, if someone finds a combo Serial/Parallel SRAM, it would greatly
simplify SoftROM implementation.  I can only find this:


Bil Herd wrote:
> Lol... I just assumed that someone made parallel flash/ee with an spi/I2C
> backdoor. Damm 40 pin devices with 35 NC pins.

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Received on 2009-05-03 23:52:15

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