Re: MAX Machine PLA

From: Segher Boessenkool <>
Date: Tue, 2 Aug 2016 16:40:30 -0500
Message-ID: <>
On Tue, Aug 02, 2016 at 10:22:28PM +0100, smf wrote:
> On 02/08/2016 20:39, Segher Boessenkool wrote:
> >The 6566 was designed before the MAX was, afaik.  It clearly was designed
> >for SRAM only fwiw.
> Interesting, I heard that the decapped 6566 showed the dram logic hacked 
> up to work with sram.
> But it has a lower number, so it probably was done first.

I have never seen a decapped 6566.  The decapped 6567/6569 clearly
shows the DRAM support stuff (RAS, CAS) was crammed in, and the same
is true for the address bus muxing.

6566 was done first, designed for video games, and never sold well in
that market.  Or so the story goes.

> Waiting for dram I think came from commodore beyond the edge. The c64 
> runs ram at 2mhz, the atari 8 bits (which was the only other home 
> computer in the c64's class) ran it's ram at 1.79mhz and launched with 
> 8k. When atari started selling them with 48k, then they used 24 x 4116 
> chips. In contrast, the c64 used 8 x 4164 chips for 64k.

The 6567 etc. support 7-bit RAMs as well, btw.  It's a metal option.


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Received on 2016-08-02 22:01:53

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