Re: Accessing the C64 memory between 65xx chips operations.

From: Pasi 'A1bert' Ojala <a1bert_at_iki.fi>
Date: Mon, 20 Apr 2020 09:58:41 +0300
Message-ID: <b3db694f-dda3-0597-d69a-d95c672ed006_at_iki.fi>
On 20.04.2020 08:56, Gerrit Heitsch wrote:
> On 4/20/20 2:29 AM, tokafondo wrote:
>> I'd like to know what happens when the VIC gets disabled by software, 
>> just
>> like when the CPU does when loading datassette programs the standard 
>> way. At
>> least, it would refresh DRAM but do the rest of the memory access apply?
>
> Yes, DRAM Refresh will happen and, as far as I know, VIC will continue 
> to do DRAM accesses to $3FFF but no longer do badlines.
VIC-II will still also perform sprite fetches for each active sprite.

>
> The only video chip I know from that time that really does free the 
> bus when it doesn't need it is TED in the 264 series. It will then 
> also double the CPU clock during that time.
>
>   Gerrit
>
>
Received on 2020-05-30 01:33:17

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