Re: 65C02S in place of 1541 6502

From: laughton_at_cyg.net
Date: Thu, 05 Dec 2019 19:53:21 -0500
Message-ID: <e4ae1201ae51614d3477431e6ea89fc1_at_cyg.net>
The pinout may be a problem.  Or not...  But here's the low-down. 

The W65C02 uses pin 36 to input the BE signal (Bus Enable). This needs
to be held high. 

Pin 5 is the MLB output -- Memory Lock.  But this pin was previously a
no-connect, so it's unlikely to cause trouble (unless the mobo PCB does
have a connection for some reason). 

Pin 1 is the VPB output.  This pin was previously VSS. 

I suggest all three pins be bent outward so they don't engage the
socket.  Then tie BE to pin 8 (VDD). 

 -- Jeff 

On 2019-12-05 19:37, Jim Brain wrote:

> Someone noted to me today that they replaced their NMOS 6502 with a WDC CMOS 65C02S in a 1541, and the unit failed to boot. 
> 
> I have verified it also does not work.  
> 
> Before I go trying to determine why things are not working, anyone already know why and what needs to be done to address? 
> 
> Jim
> 
> -- 
> Jim Brain
> brain_at_jbrain.com 
> www.jbrain.com [1]

 

Links:
------
[1] http://www.jbrain.com
Received on 2020-05-29 23:46:15

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