[Coladam] Disk Drive ROM

geoffrey oltmans oltmansg at bellsouth.net
Tue Mar 20 15:27:03 CET 2012


That makes perfect sense to me....6801s were probably one of the more expensive 
parts in the design and any chance of using rejects was probably desirable.






________________________________
From: Rich Drushel <drushel at apk.net>
To: coladam at adamcon.org
Sent: Tue, March 20, 2012 9:06:22 AM
Subject: Re: [Coladam] Disk Drive ROM


On Mon, March 19, 2012 11:09 am, geoffrey oltmans wrote:

> I've never tried doing a disk drive 6801 to see what's actually in
> it.

        I believe that all the 6801s used in the Coleco disk drives
were rejects with failed mask ROMS.  They still work as microcontrollers,
but only if used in 6803 mode with external (E)PROM.  This saved Coleco
a bit of money, and probably also allowed delaying until the last possible
second the decision about single-sided vs. double-sided disk drive.

        *Dr. D.*

-- 
Richard F. Drushel, Ph.D.            | "They fell:  for Heaven to them no hope
Department of Biology                |  imparts / Who hear not for the beating
Case Western Reserve University      |  of their hearts."
Cleveland, Ohio  44106-7080  U.S.A.  |         -- Edgar Allan Poe, "Al-Aaraaf"


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