[Coco] double speed poke ...

Robert Gault robert.gault at worldnet.att.net
Wed Apr 27 17:17:56 EDT 2005

Far as a user is concerned the clock change is immediate. If you are 
talking about emulating the 6809 or in this case the MC6883, the product 
sheet for the latter suggests that the change is not immediate and that 
a specific sequence of opcodes should be used for success.

In my own experience with a Coco1, there was no necessity to synchronize 
a sta $FFD6. Further the address dependent and full memory speed 
changes, either direction, could be used at any time. The product sheet 
states a specific sequence should be used.

Strictly speaking, test gear would be required to determine if the clock 
change is immediate or not.

Kevin Diggs wrote:
> Hi,
>     When you tell the sam to double the clock does it immediately do it 
> or does it wait for ... something?
>                     kevin
> P.S.:  On a mildy related point, someone asked about using the cassette 
> at high speed. Save and load work if you are using a good tape player. 
> The verify command does NOT work for long programs because of 
> insufficient memory refresh.

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