Re: MAX Machine PLA

From: Gerrit Heitsch <>
Date: Sun, 7 Aug 2016 15:52:22 +0200
Message-ID: <>
On 08/07/2016 03:04 PM, smf wrote:

> AFAICT they originally planned to make a dram version for the P500 and the static ram version only happened when the ultimax project picked up the chips but they needed to make it cheaper.

Usually, MOS counted upwards, meaning the 6566 would have come before 
the 6567. So either the static version came first or there was another 
version, like a 6565. There are a few numbers missing between the 6561 
(PAL-VIC for VIC-20) and the 6566 after all.

> The 6509 appears to have been made for the P500 and the 6510 for the
> ultimax. The c64 on the other hand was then just thrown together with
> the chips they had (hence the PLA).

I read somewhere, that the PLA was used to allow starting the PCB design 
before all the logic was ready. With the PLA you could make the PCB and 
have a 28pin socket waiting for the guys who did the logic.


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Received on 2016-08-07 14:00:45

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