Re: MAX Machine PLA

From: Segher Boessenkool <segher_at_kernel.crashing.org>
Date: Sat, 30 Jul 2016 07:55:28 -0500
Message-ID: <20160730125528.GC32017@gate.crashing.org>
On Sat, Jul 30, 2016 at 01:56:36PM +0200, Gerrit Heitsch wrote:
> >In the max the PLA also does the color ram to cpu bus switching.
> 
> That's something that can be handled with a CD4066, as in the C64. To me 
> it sounds as if the PLA in the Max machine is rather simple and it 
> should be possible to replace it with a much smaller logic chip than 
> needed for the PLA in the C64.

It isn't really a PLA, it is a custom chip just like the 6702 (which
is a bunch of shift registers, used for a "security" dongle).

There is hardly any logic needed for the 6703 functionality, mostly
just the pad drivers ;-)


Segher

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Received on 2016-07-30 13:00:52

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