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 19:13, 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.