Difference between revisions of "Palette Value Register"
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Format is RRRGGGBB - Note the lowest blue bit of colour (ninth bit) will be set to an OR between bit 1 and bit 0. | Format is RRRGGGBB - Note the lowest blue bit of colour (ninth bit) will be set to an OR between bit 1 and bit 0. | ||
| − | After the write, the palette index is auto-incremented to the next index, if the auto-increment is enabled at {{NextRegNo|$43}}. | + | After the write, the palette index is auto-incremented to the next index, if the auto-increment is enabled at {{NextRegNo|$43}}. And also the index of {{NextRegNo|$44}} is reset, so the next write there will be considered as first byte of colour. |
Read does not auto-increment the index, and reads always the top 8 bits of colour from palette, to read the 9th bit of colour, use {{NextRegNo|$44}} in tandem with value from this register. | Read does not auto-increment the index, and reads always the top 8 bits of colour from palette, to read the 9th bit of colour, use {{NextRegNo|$44}} in tandem with value from this register. | ||
The modified palette remains until a Hard Reset. | The modified palette remains until a Hard Reset. | ||
Latest revision as of 17:06, 11 November 2019
| Number | $41 |
|---|---|
| Readable | Yes |
| Writable | Yes |
| Short Description | Use to set/read 8-bit colours of the ULANext palette. |
Bits 7-0 = Eight bit colour for the palette index selected by the Palette Index Register ($40).
Format is RRRGGGBB - Note the lowest blue bit of colour (ninth bit) will be set to an OR between bit 1 and bit 0.
After the write, the palette index is auto-incremented to the next index, if the auto-increment is enabled at Enhanced ULA Control Register ($43). And also the index of Enhanced ULA Palette Extension ($44) is reset, so the next write there will be considered as first byte of colour.
Read does not auto-increment the index, and reads always the top 8 bits of colour from palette, to read the 9th bit of colour, use Enhanced ULA Palette Extension ($44) in tandem with value from this register.
The modified palette remains until a Hard Reset.