Date   : Fri, 03 Dec 2004 23:26:26 -0000
From   : "Andy Welburn" <warlords@...>
Subject: Re: Eprom programming problem

I can say with absolute certainty that a 27c128 and a 27128 differ in
their programming algorithms, and/or their programming voltages.. modern
programmers (I use a Conitec GALEP-III) will spot the incorrect device
and prevent writing, if you are using a BBC eprom programmer, I doubt
that this will pick up the difference because I doubt any BBC programmer
ever had pin-programmable capability. Therefore you could have nuked the
eprom, but you never know, they are pretty resilient.

I work on vintage video arcade pcbs, and I've tried programming
27c128's, and I can confirm in my Sidewise Ram/Rom board enabled BBC B,
that they do not work.. they have to instead be plain jane 27128's.. I
have mainly AMD, Intel and SGS-Thompson devices, and I program them
using an Intel algorithm, and they work in my (borrowed) BBC.

I have some roms in this borrowed BBC that I'm not sure are 'out there'
is there a definitive list of roms somewhere on the net (admittedly I
haven't looked too far), one in particular is '*help' I can dump them
easy as pie, I have about 12? In the sidewise right now, none of which I
really use :)

Andy Welburn
www.andys-arcade.com

> -----Original Message-----
> From: Majordomo List Manager [mailto:majordomo@...] On Behalf
Of
> John & Helen Simpson
> Sent: 03 December 2004 20:43
> To: bbc-micro@...
> Subject: [BBC-Micro] Eprom programming problem
> 
> Hi there,
> 
> I have been trying to program an Eprom using Angus Duggan's design for
> an Eprom programmer (as seen on 8bs and on Angus' own site). Basically
> my problem is that the Eprom programmer runs OK, but the resultant
Eprom
> is not recognised by the BBC.
> 
> I think I have worked out what the problem is - I have used a CMOS
> 27C128 whereas the instructions for the programmer seem to imply that
> you have to use a plain 27128. I reckon that the higher programming
> voltage might have fried my poor CMOS eprom. Do you think I am on the
> right track with this diagnosis, and if so is it still possible to buy
> 27128s? I think I probably bought the CMOS one because it was the only
> type of 128kBit eprom in the catalogue at the time.
> 
> Symptoms:
> 
> 1) When I plug the Eprom (in a cartridge) into the Master and try to
> *SRSAVE the relevant bank, the command fails, presumably because the
> machine cannot detect any ROM at that position, not even a garbled
one.
> 
> 2) If I try to use the Eprom programmer software to save the contents
of
> the Eprom, it reports an Eprom programmer error at a location above
> &A000. Yet the Eprom was (when new) verified OK and written to
> successfully.
> 
> This is just a messing about in my spare time sort of project but I'd
be
> grateful for some ideas.
> 
> Thanks
> 
> --
> John
>