Difference between revisions of "Expansion Bus Control Register"
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(Ped7g moved page Expansion Bus Control Register to Expansion Bus Enable Register: core 3.0.5 change/refresh) (Tag: New redirect) |
(core 3.0.5 changes/refresh) |
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(One intermediate revision by the same user not shown) | |||
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− | + | {{NextRegister | |
+ | |Number=$81 | ||
+ | |Readable=Yes | ||
+ | |Writable=Yes | ||
+ | |ShortDesc=Expansion bus controls | ||
+ | }} | ||
+ | {|class="wikitable" | ||
+ | ! Bit !! Description | ||
+ | |- | ||
+ | | 7 || 1 if ROMCS is being asserted on the expansion bus (Read only, write 0) | ||
+ | |- | ||
+ | | 4 || 1 to propagate the max CPU clock at all times including when the expansion bus is off | ||
+ | |- | ||
+ | | 1-0 || max CPU speed when the expansion bus is on (currently fixed at 00 = 3.5MHz) | ||
+ | |} | ||
+ | |||
+ | 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) |
Latest revision as of 00:07, 5 December 2019
Number | $81 |
---|---|
Readable | Yes |
Writable | Yes |
Short Description | Expansion bus controls |
Bit | Description |
---|---|
7 | 1 if ROMCS is being asserted on the expansion bus (Read only, write 0) |
4 | 1 to propagate the max CPU clock at all times including when the expansion bus is off |
1-0 | max CPU speed when the expansion bus is on (currently fixed at 00 = 3.5MHz) |
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)