NextPort:$FF3B: Difference between revisions
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If palette group is selected, the palette value stored at the current ula+ palette index is returned | If palette group is selected, the palette value stored at the current ula+ palette index is returned | ||
If the mode group is selected, bit 0 = 1 to indicate ULA+ is enabled | If the mode group is selected, bit 0 = 1 to indicate ULA+ is enabled | ||
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If the palette group is selected, a palette value is written to the current ula+ palette index | If the palette group is selected, a palette value is written to the current ula+ palette index | ||
If the mode group is selected, bit 0 = 1 to enable ULA+, 0 to disable ULA+ | If the mode group is selected, bit 0 = 1 to enable ULA+, 0 to disable ULA+ | ||
For ULA+ i/o ports, all colours are read and written in 8-bit format GGGRRRBB. The 9th blue bit is automatically generated | For ULA+ i/o ports, all colours are read and written in 8-bit format GGGRRRBB. The 9th blue bit is automatically generated | ||
as the logical OR of the two other blue bits. | as the logical OR of the two other blue bits. | ||
Revision as of 13:55, 21 February 2026
| Port Number | $FF3B |
|---|---|
| Decimal | |
| Short desc. | ULA+ Data |
| Bit Mask | |
| Readable | Yes |
| Writable | Yes |
| Subsystem |
(R)
If palette group is selected, the palette value stored at the current ula+ palette index is returned
If the mode group is selected, bit 0 = 1 to indicate ULA+ is enabled
(W)
If the palette group is selected, a palette value is written to the current ula+ palette index
If the mode group is selected, bit 0 = 1 to enable ULA+, 0 to disable ULA+
For ULA+ i/o ports, all colours are read and written in 8-bit format GGGRRRBB. The 9th blue bit is automatically generated as the logical OR of the two other blue bits.