Difference between revisions of "Enhanced ULA Control Register"
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(Clarified the difference between bits 6:4 and 3:1.) |
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{{NextRegister | {{NextRegister | ||
|Number=$43 | |Number=$43 | ||
| − | |Readable= | + | |Readable=Yes |
|Writable=Yes | |Writable=Yes | ||
| − | |ShortDesc=Enables or disables | + | |ShortDesc=Enables or disables Enhanced ULA interpretation of attribute values and toggles active palette. |
}} | }} | ||
| + | {| class="wikitable" | ||
| + | ! Bit !! Function | ||
| + | |- | ||
| + | | 7 || 1 to disable palette index write auto-increment | ||
| + | |- | ||
| + | | 6-4 || Select palette for reading or writing | ||
| + | |- | ||
| + | | 3 || Select Sprites palette (0 = first palette, 1 = second palette) | ||
| + | |- | ||
| + | | 2 || Select Layer 2 palette (0 = first palette, 1 = second palette) | ||
| + | |- | ||
| + | | 1 || Select ULA palette (0 = first palette, 1 = second palette) | ||
| + | |- | ||
| + | | 0 || Enable ULANext mode if 1. (0 after a reset) | ||
| + | |} | ||
| + | n.b. Bits 6-4 select palette for reading or writing whereas bits 3-1 select the palette for the display signal generator. | ||
| + | |||
| + | Possible bits 6-4 for palette select (bit 6 selects first/second, 5-4 select type): | ||
{| class="wikitable" | {| class="wikitable" | ||
| − | ! | + | ! Bits 6-4 !! selects |
| + | |- | ||
| + | | %000 || ULA first palette | ||
| + | |- | ||
| + | | %100 || ULA second palette | ||
| + | |- | ||
| + | | %001 || Layer 2 first palette | ||
| + | |- | ||
| + | | %101 || Layer 2 second palette | ||
| + | |- | ||
| + | | %010 || Sprites first palette | ||
|- | |- | ||
| − | | | + | | %110 || Sprites second palette |
|- | |- | ||
| − | | | + | | %011 || Tilemap first palette |
|- | |- | ||
| − | | | + | | %111 || Tilemap second palette |
|} | |} | ||
| + | |||
| + | Write will also reset the index of {{NextRegNo|$44}}, so the next write there will be considered as first byte of colour. | ||
Latest revision as of 20:13, 31 December 2020
| Number | $43 |
|---|---|
| Readable | Yes |
| Writable | Yes |
| Short Description | Enables or disables Enhanced ULA interpretation of attribute values and toggles active palette. |
| Bit | Function |
|---|---|
| 7 | 1 to disable palette index write auto-increment |
| 6-4 | Select palette for reading or writing |
| 3 | Select Sprites palette (0 = first palette, 1 = second palette) |
| 2 | Select Layer 2 palette (0 = first palette, 1 = second palette) |
| 1 | Select ULA palette (0 = first palette, 1 = second palette) |
| 0 | Enable ULANext mode if 1. (0 after a reset) |
n.b. Bits 6-4 select palette for reading or writing whereas bits 3-1 select the palette for the display signal generator.
Possible bits 6-4 for palette select (bit 6 selects first/second, 5-4 select type):
| Bits 6-4 | selects |
|---|---|
| %000 | ULA first palette |
| %100 | ULA second palette |
| %001 | Layer 2 first palette |
| %101 | Layer 2 second palette |
| %010 | Sprites first palette |
| %110 | Sprites second palette |
| %011 | Tilemap first palette |
| %111 | Tilemap second palette |
Write will also reset the index of Enhanced ULA Palette Extension ($44), so the next write there will be considered as first byte of colour.