Re: Hardware emulation of 6509 using 6502?

From: Jim Brain <brain_at_jbrain.com>
Date: Fri, 2 Mar 2018 08:10:51 -0600
Message-ID: <6a754bf0-41b3-1253-5979-a5e268ef6d9d@jbrain.com>
On 3/2/2018 6:44 AM, Michał Pleban wrote:
> Hello!
>
> smf wrote:
>
>> It won't work for the p500, which probably does exist.
> The P500 has SRAM in bank F just like the 610, so I think it could work.
> At least it's an idea worth a quick check (assuming that Jim has a P500?)
Sorry, no p500 here. I'm not eve sure how I acquired this B, to be honest.

I could indeed change the code to handle the condition via dummy bank 
reads, but the PCB has to be modified anyway.  At present, the CPLD 
sticks out beyond the 6509 footprint on the bottom (by pin 20/21), but 
it interferes with the B keyboard cable.  So, it has to be moved to be 
at the top (pin 1/40) anyway.  Right now, I sidestepped the problem with 
a riser on the socket, but then the B PSU interferes when attempting to 
close the case.

(Sure, should have noticed this when designing the board, but who pays 
attention to those details when one is just fiddling with an idea like 
this late at night?  I suppose all of you do, but I did not).

Jim

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Received on 2018-03-02 16:00:03

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