Re: 6510 I/O port as chip selects to expand memory

From: Claudio Sánchez <tokafondo_at_gmail.com>
Date: Thu, 18 Nov 2021 18:59:27 +0000
Message-ID: <e17f5779-3da7-b178-9da9-8c5a01167948_at_gmail.com>
> On 11/18/2021 6:34 AM, Michał Pleban wrote:
>> smf wrote:
>>
>>> Be careful how you design it, the 6509 based cbm2 pretty much did what
>>> you're suggesting and programming them was terrible.
>> The 6509 had an additional functionality: the memory bank for LDA (xx),Y
>> and STA (xx), Y instrutions was selected separately.
> 
> Not sure OP's intent, but they could use this project (which Michal knows about, just putting here for the OP):
> 
> https://github.com/go4retro/Nu6509
> 
> To maybe implement some help for the banking that's not so restrictive.
> 
> I can say that, issues with banking aside, I'd recommend adding an IO port to a 6502, like so:
> 
> https://github.com/go4retro/Nu6510

Why didn't you added lines 6 and 7? It wouldn't had hurt...
  
> To avoid using the expensive 6510 directly.
> 
> Here's a version for the +4:
> 
> https://github.com/go4retro/Nu7501
> 
> Like the gitlab project mentioned earlier.
> 
> 
> 
> 
Received on 2021-11-18 21:00:02

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