> What is $29E used for?
> Could these be accessing the NUSIZx registers?
>
> BTW, thanks Eckhard for answering my question about the $288 address. I
> looked at Jawbreaker again and yes this is the same as SWCHA. How does
> that work? Am I missing something? These addresses don't show in any
> documentation I have.
The TIA and RIOT don't completely decode the 6507 addressing lines so there
are "shadows" throughout the $0000-$0FFF address range.
The TIA !CS0 and !CS3 are connected to A12 and A7, and it fully decodes
A0-5. So the TIA is mapped to address %0xxxx0x?????? The RIOT CS1, !CS2
and !RS (RAM select) are connected to A7, A12 and A9 respectively and it
fully decodes A0-6. So the RIOT is mapped to addresses %0xxRx1???????
$29E = %0001010011110 since A7 ($080) is high, it's a RIOT address. Since
A9 ($200) is high, it's a RIOT register address. RIOT register $1E is
(according to
http://www.6502.org/documents/datasheets/mos/mos_6532_riot.pdf) the same as
TIM8T except it enables the interrupt from timer to !IRQ.
