Re: Hardware emulation of 6509 using 6502?

From: Jim Brain <brain_at_jbrain.com>
Date: Mon, 16 Jul 2018 21:29:34 -0500
Message-ID: <c1cc6d12-249c-42fa-99c9-133d556d08f4@jbrain.com>
While I loathe to throw shade on any of these ideas, most require a 
level of effort that I am, quite frankly, not willing to invest. 
Anything beyond the ABORT idea will require moving to a xc95144xl 
device, which cannot be placed in the vqfp64 footprint.  Thus, a 
completely new board design would be needed.

The simplest idea is:

If you need the SO line, use a 65C02S.

WDC recommends not using the SO line anyway, and few things use it. As 
far as I can tell, no part of the B128 uses the SO line.  It's sole 
purpose is to be on the co-processor slots for potential co-proc usage.

If I can find an easy way to route the ABORT and 6509 SO pin to the 
CPLD, I'll add smf's idea.

Jim
Received on 2018-07-17 05:00:04

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