Expansion Bus Enable Register

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Revision as of 22:58, 4 December 2019 by Ped7g (talk | contribs) (core 3.0.5 changes/refresh)
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Number $80
Readable Yes
Writable Yes
Short Description Expansion bus enable/config
Bit Description
Values affecting machine immediately
7 1 to enable Expansion Bus
5 1 to disable I/O cycles and ignore IORQULA
4 1 to disable memory cycles and ignore ROMCS
After soft reset (will be copied to bits 7-4)
3 1 to enable Expansion Bus
1 1 to disable I/O cycles and ignore IORQULA
0 1 to disable memory cycles and ignore ROMCS

Set to 0 upon hard reset.

(new register since core 3.0.5)

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