[Coco] What do you make of this non-approved HSCREEN mode?

Paul Fitch pfitchjr at bellsouth.net
Sun Jun 7 11:21:30 EDT 2009


> The control byte at $FF99 changes what the video circuitry shows in
> Coco3 mode. The MMU bytes control what part of memory you 
> have actual access to for reading or making changes.
> In light of this, care to modify what you said in your last 
> paragraph? :)

Not particularly<g>.  I'm not an expert, but I'll assume that the paragraph
above comes from the "official" documentation.  Yet you have evidence that
"undocumented" things are happening.  How do you reconcile the differences?
You can't until you fully understand whats happening.

You obviously have more experience with the coco's hardware and software
than I do.  But part of my day job is trouble shooting problems.  And I've
learned that you can't fix a problem, you can't even accurately explain it,
until you know everything that's going on.  

That program you wrote shouldn't do what it is doing.  Ie, we don't have the
full picture.    

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