Date   : Thu, 26 Jan 2012 14:19:39 +0000
From   : afra@... (Phill Harvey-Smith)
Subject: 6502 chip available again

On 26/01/2012 13:56, David Glover wrote:
> Apparently, the W65C02S6TPG-14 ? its current name ? is pin and
> software compatible with its grandfather, a 1975 drawing board design

It's *ALMOST* pinout compatible, pins 5 and 36 are no connect on the 
original chip and MLB and BE on the WDC chip. MLB is an output so can be 
left unconnected, however BE is a bus enable input that must be high to 
enable the busses on the chip, so must be pulled up, this of course is 
simple enough to do by soldering a resistor between pins 36 and 8 (VDD).

Anyway, it would be a good move to check the datasheet :) :) :) With 
this pullup I have used the WDC chip in the BBC, at least far enough to 
verify that the machine starts OK. The Atom Rom-ram board has jumpers to 
select either the original 6502 or the WDC chip, not tried it in an 
Electron but see no reason why it should now work.

WDC also do a compatible 65C22 (also 14MHz rated), woner if Mouser stock 
them too.

Cheers.

Phill.