[Coco] Help with some HiRes CoCo 3 MMU settings
robert.gault at att.net
Wed Dec 7 21:13:14 EST 2016
Glen Hewlett wrote:
> Hi Robert,
> Thanks for the example code, It works fine for the FIRQ as it is, and I can hopefully use this to get my IRQ version working. I noticed that in your Interrupt section the first thing you do is a “lda $FF93” is there a reason for reading the FIRQENR every time the interrupt is called?
> Just trying to learn…
> Thanks again. Your code will help.
I read $FF93 because I chose to use FIRQ instead of IRQ. Look at the beginning
of the code where I installed FIRQ,pcr and turned on FIRQ with
In the case of the GIME, reading $FF92 or $FF93 clears the interrupt. For cpu
interrupts, you would clear the interrupt flags at $FF01, $FF03, $FF21, and
$FF23; bit#7 (0-7) for each.
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