Date   : Sun, 06 Feb 2005 12:33:56 +0100
From   : John Kortink <kortink@...>
Subject: Re: BBC SWRAM module

On Sun, 6 Feb 2005 03:12:04 +0000 (GMT), Greg Cook wrote:

>[...]
>
>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.

It samples NR/W nand 2MHzE, which makes for a cleaner and
safer write strobe, because it is then synced to the data
transfer part of the bus cycle, as it should be (instead
of relying on accidental 6502 behaviour of defaulting to
'read' on R/nW).


John Kortink

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