ULA Palette Control Register: Difference between revisions

Revision as of 21:48, 22 December 2018

Number	TBRegisterNumber::$43
Readable	TBRegisterReadable::Yes
Writable	TBRegisterWritable::Yes
Short Description	ShortDesc::Enables or disables ULANext 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	Disable the standard Spectrum flash feature to enable the extra colours. (0 after a reset)

Possible bits 6-4 for palette select (bit 6 selects first/second, 5-4 select type):

@@ Line 1: / Line 1: @@
 {{NextRegister
 |Number=$43
-|Readable=No
+|Readable=Yes
 |Writable=Yes
 |ShortDesc=Enables or disables ULANext interpretation of attribute values and toggles active palette.
 }}
 {| class="wikitable"
 ! Bit !! Function
 |-
-| 7 || Reserved
+| 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 || Disable the standard Spectrum flash feature to enable the extra colours. (0 after a reset)
+|}
+Possible bits 6-4 for palette select (bit 6 selects first/second, 5-4 select type):
+{| class="wikitable"
+! Bits 6-4 !! selects
 |-
-| 6 || Select normal (0) or second (1) palette to read/write
+| %000 || ULA first palette
 |-
-| 4-5 || Select ULA (00), Layer 2 (01) or sprite (10) palette to read/write
+| %100 || ULA second palette
 |-
-| 3 || Enable second palette on Sprites
+| %001 || Layer 2 first palette
 |-
-| 2 || Enable second palette on Layer 2
+| %101 || Layer 2 second palette
 |-
-| 1 || Enable second palette on ULANext
+| %010 || Sprites first palette
 |-
-| 0 || Enable ULANext attributes
+| %110 || Sprites second palette
 |}