Date   : Sun, 06 Feb 2005 03:12:04 +0000 (GMT)
From   : Greg Cook <debounce@...>
Subject: Re: BBC SWRAM module

On Sun, 06 Feb 2005 11:30:16 +1300 (NZDT), Michael Foot wrote: 
> Hi,
> 
> I have discovered in a Model B what looks like a SWRAM module.
> However it has 
> a number of wires coming off it including 1 running to the keyboard.
> There is a picture of it here:
> http://homepages.paradise.net.nz/mjfoot/SRAM_1.jpg
> 
> I'd like to know more about it if anyone has seen such a setup
> before. The 
> wire running to the keyboard looks very strange to me.

No info on who made it, but the orange wire is connecting a 74something
output to CAS LED.  The cassette indicator is apparently meant to flash
when the SRAM is being written to.  The blue and grey wires are unclear
but they may be for the module to service its own and the neighbouring
socket (2x16K SRAM banks.)

The yellow wire is sampling /R/W (SRAM mods normally take R//W from a
nearer pin) but there are spare gates on the "module" to invert the
signal.

Greg



       
       
               
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