Tilemap Control Register

Number	TBRegisterNumber::$6B
Readable	TBRegisterReadable::Yes
Writable	TBRegisterWritable::Yes
Short Description	ShortDesc::Controls Tilemap mode.

Bit	Function
7	1 to enable the tilemap
6	0 for 40x32, 1 for 80x32
5	1 to eliminate the attribute entry in the tilemap
4	palette select (0 = first Tilemap palette, 1 = second)
3-2	Reserved, must be 0
1	1 to activate 512 tile mode (bit 0 of tile attribute is ninth bit of tile-id) 0 to use bit 0 of tile attribute as "ULA over tilemap" per-tile-selector
0	1 to enforce "tilemap over ULA" layer priority

Bits 7 & 6 enable the tilemap and select resolution.

Bit 5 changes the structure of the tilemap so that it contains only 8-bit tilemap-id entries instead of 16-bit tilemap-id and tile-attribute entries.

If 8-bit tilemap is selected, the tilemap contains only tile numbers and the attributes are taken from {{#ask: TBRegisterNumber::$6C }} ($6C).

Bit 4 selects one of two tilemap palettes used for final colour lookup.

Bit 1 enables the 512-tile-mode when the tile attribute (either global in $6C or per tile in map data) contains ninth bit of tile-id value. In this mode the tiles are drawn under ULA pixels, unless bit 0 is used to force whole tilemap over ULA.

Bit 0 can enforce tilemap over ULA either in 512-tile-mode, or even override the per-tile bit selector from tile attributes. If zero, the tilemap priority is either decided by attribute bit or in 512-tile-mode it is under ULA.