[Coco] OS9 vs Flex

[John Kent]

Oh OK,

yep. I had a feeling what I was saying was wrong.

John.

On 2/01/2012 7:30 AM, Darren A wrote:
> Hi John, There is no address counter, and the FDC does not access the 
> RAM. The CPU executes code to enable the HALT line and then enters an 
> infinite loop to move data to or from the FDC. Since HALT is connected 
> to DRQ, the CPU only runs when the FDC requests a data transfer. When 
> the operation is complete, the FDC asserts INTRQ which disables the 
> HALT line and generates an NMI to break out of the loop. Darren 
> -- Coco mailing list Coco at maltedmedia.com 
> http://five.pairlist.net/mailman/listinfo/coco 

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