RE: [stella] 7800 programs -- potential problems?

Subject: RE: [stella] 7800 programs -- potential problems?
From: Eckhard Stolberg <Eckhard_Stolberg@xxxxxxxxxxxxxxxxxxxxx>
Date: Tue, 25 Jan 2000 13:21:20 +0100
>passes this through to the HLT line.  I don't see any way around that, unless
>my schematic is wrong, so I guess you only get one write to the control reg?

In my BIOS I can write to the control register more than once. For
example, every time a transfer between the 7800 and the PC is initiated,
I first switch in the game ROM to transfer the data and then I switch back
to the BIOS ROM to display the menu again. And I can do several transfers
without having to turn the 7800 off and on again. I only access the control
register through $01 or $01,X , so maybe it's the address that matters?

I also always have the MARIA mode enabled, so maybe this is just a trap
for the TIA mode? To enable TIA mode you have to set bit 3 HIGH, so maybe
it's this bit that gets passed through this circuit, so that you can't
switch back to MARIA mode when you have enabled TIA mode without locking
it in?

Thanks, Eckhard Stolberg

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