[Coco] Help with some HiRes CoCo 3 MMU settings
msmcdoug at iinet.net.au
Wed Dec 7 07:06:21 EST 2016
On 7/12/2016 3:23 PM, Glen Hewlett wrote:
> With Mame’s debugger I can see
> the banks of memory have wiped out my graphics screen and my program
> and filled it all with a bunch of $CD values in my RAM. Does this
> sound familiar to anyone maybe you know what I’m missing or doing
> wrong that would cause such a thing to happen.
$CD is the value I see in MAME/MESS for uninitialised RAM. Sounds like
your banks are being inadvertently switched.
I can't see anything immediately obvious in your setup. Similar code to
what I use for setting up my video; pages $38/$39 @$0000 (which I think
is the default anyway).
I'd place watchpoints on the MMU bank/task registers ($FFA0-$FFA3) and
see if anything is hitting them that shouldn't be. Otherwise a
watchpoint on your codespace will reveal that page being explicitly
overwritten, as opposed to being switched out. Shouldn't be difficult to
track down using a watchpoint!?!
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