Date : Fri, 10 Dec 2004 14:55:08 -0000
From : "Chris Richardson" <chris@...>
Subject: Re: Eprom Programmer
Hi All
Thanks to Mick for pointing the error in the diagram out. The ones on the
8BS website were incorrect. I am in the process of changing them to what
Mick says they should be. They should be corrected on the main page as you
read this. I am however looking for a corrected pdf version if anyone can
help please
Chris
8-Bit Software the BBC and Master Public Domain Library
http://8bs.com
DON'T BOUNCE SPAM! It most likely will not go back to the spammer but to
some innocent person such as myself
----- Original Message -----
From: "Mick Champion" <mick@...>
To: <bbc-micro@...>
Sent: Friday, December 10, 2004 1:24 PM
Subject: [BBC-Micro] Eprom Programmer
> To the BBC list,
>
> Sprow wrote :
> Sprow> 27128 - NMOS, 21V for Vpp
> Sprow> 27128A - NMOS, 12.5V for Vpp
> Sprow> 27C128 - CMOS, far too weedy to drive the bus
>
> I have had 3 working 27C128s installed in my model B for two years now.
> All
> were programmed using a programmer that I built using Angus's superb
> design,
> so it is possible. The 20k resistor on the TL497A had to be changed to 15K
> to
> reduce the programming voltage to 13v. The resulting heat reduction inside
> the
> BBC is great as C128s hardly get warm.
>
>
> There was a also a mistake in the 1985 version of EPROG.PDF. The correct
> wiring, is for both 5Ds on the two 74LS374's to be strapped to PB4, and
> both
> 6Ds to PB5. On my PDF version, the right hand 74LS374, shows 'incorrectly'
> that 5D goes to PB5 and 6D to PB4. The PDF may have been updated by now,
> ignore if it has.
>
>
> Mick.
>
>
>
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