Date   : Sun, 10 May 2009 22:42:38 +0100
From   : jumbos.bazzar@... (Mark Haysman)
Subject: BBC B roms - Large flash chip - Help please -.o

Hi.

0-15 should be easy, just wire it the same, but the 4 high address lines 
connect to the 4 ROM decoder outputs of the LS163.

Doing it so it only selects "some" of the range will require a bit of logic, 
a single 16V8 PAL should be able to do it, or maybe even a few gates of a 
TTL, but would need to enable the onboard ROMs as well as select the Flash 
at the appropriate time.

Mark.

----- Original Message ----- 
From: "adam colley" <hideki.adam@...>
To: "BBC micro mailing list" <bbc-micro@...>
Sent: Sunday, May 10, 2009 10:31 PM
Subject: [BBC-Micro] BBC B roms - Large flash chip - Help please -.o


> Hihi
>
> I have here a 39SF020 256KB flash chip which my willem seems quite happy 
> with
>
> Is there any way I can fit this inside a BBC so it occupies all the
> rom sockets from 0 to 15? (or 0-13 so I can put the GoMMC somewhere)
> perhaps on a small daughterboard for one of the existing rom sockets
> with flying leads for the additional address lines? not sure exactly
> how it works but I've seem similarish things being sold before
>
> I'd use the sideways rom board but the pins got damaged when moving it
> between machines (and although someone in here has an identical
> replacement for sale, my email asking about it went unanswered), it's
> not been working reliably since those got replaced, it sees the roms
> more or less but there seems to be some occasional corruption that
> makes it virtually unusable -.- (ATPL sidewise board, has pins that
> connect to the MOS and ADC chip sockets, I have another one that goes
> into the 6502 socket but that one flatly refuses to work with GoMMC
> under any circumstances)
>
> but aye, if I could use this flash chip for the roms it'd be a lot
> easier to change them, not having to mess about finding eproms that
> haven't succumbed to bit rot and erase them etc.
>
> Thanks -.o
>
> -- 
> Hideki.Adam
>
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