Re: Theorizing about hack / mod / expansion of a C64 motherboard.

From: Gerrit Heitsch <gerrit_at_laosinh.s.bawue.de>
Date: Thu, 30 Jul 2020 07:06:58 +0200
Message-ID: <6cbfa498-e73e-b40e-4fde-4adc8c3eeead_at_laosinh.s.bawue.de>
On 7/30/20 3:37 AM, tokafondo wrote:
> Wavestar wrote
>> Lets remember that the Commodore 64's system bus was a 14 to 17 MHz
>> computer (Y1 clock) even though the CPU is ~1 MHz. This means whatever is
>> emulating the C64 must be able to emulate the system bus and behavior of
>> multiple chips at 14-17 MHz.
>>
>> (http://cbm-hackers.2304266.n4.nabble.com/65816-emulating-a-C64-tp4669364p4669376.html)
> 
> I knew that the VIC-II run at 8Mhz internally, but not that the system bus
> run at 14-17 Mhz. If this is the case, it seems that the C64 motherboard can
> support actually high speed clocks... for a vintage computer, of course.

No, because these high clockspeeds are only found around VIC and only on 
a few traces. Everything else runs on a much more sedate speed of around 
2 MHz max. (/RAS and /CAS for example) or even slower (the CPU at about 
1 MHz).

  Gerrit
Received on 2020-07-30 08:00:02

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