Re: Patching in a CBM disk drive connection in a C64 case.

From: Jim Brain <brain_at_jbrain.com>
Date: Wed, 30 Mar 2022 10:36:32 -0500
Message-ID: <52710c47-1aed-ef8f-6adf-1a5e924270bd_at_jbrain.com>
On 3/30/2022 4:46 AM, smf wrote:
> The TIB drive uses DMA though
>
> https://github.com/sjgray/TIB-001-Cart
>
> You would need a "Goldstar GM82C765B FDC chip", or clone it with a
> CPLD/FPGA.
>
> I'm not sure how many people would actually want a TIB drive though....
>
> On 28/03/2022 16:27, Gerrit Heitsch wrote:
>
>> No, not using DMA, just a different I/O-port. That adapter you plug
>> into the plus/4 contains a PLA (251641-03) and a 6523T (6525 in
>> 28pin). There is no DMA involved.
>>
>
The IC supports DMA, but does the cart design actually use it?  808X DMA 
is markedly different in operation than C64 DMA, and I don't see enough 
logic on that board to glue the two concepts together.  It looks like 
polling mode is used.

Jim

-- 
Jim Brain
brain_at_jbrain.com  
www.jbrain.com
Received on 2022-03-30 18:00:07

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