Internal Port Decoding b0-7 Register: Difference between revisions

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|Readable=Yes
|Readable=Yes
|Writable=Yes
|Writable=Yes
|ShortDesc=Enabling internal ports
|ShortDesc=Enabling internal ports decoding
}}
}}
{|class="wikitable"
{|class="wikitable"

Revision as of 09:07, 12 November 2019

Next Register Number $82
Readable Yes
Writable Yes
Short Description Enabling internal ports decoding
Bit Description
7 Enabling IO:$xx37 (also MD2 controller)
6 Enabling IO:$xx1F (also MD1 controller)
5 Enabling IO:$xx6B
4 Enabling +3 floating bus
3 Enabling IO:$1FFD
2 Enabling IO:$DFFD
1 Enabling IO:$7FFD
0 Enabling IO:$xxFF

All bits are set to 1 upon soft reset.

(note: Next registers with number higher than $7F are inaccessible from Copper code)