Re: 'Frankenstein' Disk Drives, Done Cheap

From: Gerrit Heitsch <>
Date: Mon, 28 Apr 2014 22:54:32 +0200
Message-ID: <>
On 04/28/2014 10:40 PM, smf wrote:
>> Yes, but why exactly? The CPU has handed the value (whatever it is) to
>> the register hundreds of ns before VIC puts his addresses on the bus.
>> Everything should be stable by then. Why isn't it? And this only
>> happens on some VICs, others don't have that problem.
> VIC assumes certain things have been done in previous cycles based on
> what it knows now. Which is pretty much how all the VIC effects work
> (opening the borders etc).

The way I understand it, the timing inside VIC is mostly generated by 
counters and comperators that kick off actions when a counter reaches a 
certain value.

I understand what happens on the outside, what I'm interested in is what 
happens inside VIC, meaning what part of the logic misfires that long 
after all the registers have been loaded.


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Received on 2014-04-28 21:07:52

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