ULA Palette Control Register: Difference between revisions

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Rewording a bit and adding info from web docs.
m Xalior moved page Enhanced ULA Control Register to ULA Palette Control Register: match formal nextreg.txt name
 
(7 intermediate revisions by 5 users not shown)
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|Readable=Yes
|Readable=Yes
|Writable=Yes
|Writable=Yes
|ShortDesc=Enables or disables ULANext interpretation of attribute values and toggles active palette.
|ShortDesc=Enables or disables Enhanced ULA interpretation of attribute values and toggles active palette.
}}
}}
{| class="wikitable"
{| class="wikitable"
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| 1 || Select ULA palette (0 = first palette, 1 = second palette)
| 1 || Select ULA palette (0 = first palette, 1 = second palette)
|-
|-
| 0 || Disable the standard Spectrum flash feature to enable the extra colours. (0 after a reset)
| 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):
Possible bits 6-4 for palette select (bit 6 selects first/second, 5-4 select type):
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|-
|-
| %110 || Sprites second 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 11:03, 14 October 2025

Number TBRegisterNumber::$43
Readable TBRegisterReadable::Yes
Writable TBRegisterWritable::Yes
Short Description ShortDesc::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 {{#ask: TBRegisterNumber::$44 }} ($44), so the next write there will be considered as first byte of colour.