A screen mode similar to hardware text linked to the ULA modes which allows for either 40x32 or 80x32 16-colour 8x8 tiles.
The tilemap is enabled using Nextreg $6B (107) Tilemap Control
bit 7: 0=disable tilemap, 1=enable tilemap bit 6: 0=40x32, 1=80x32 bit 5: 0=attributes in tilemap, 1=no attributes in tilemap bit 4: 0=primary palette, 1=secondary palette bits 3-2: reserved (0) bit 1: 0=256 tile mode, 1=512 tile mode bit 0: 1=tilemap over ULA
The tilemap consists of two data areas: tile descriptions and an actual tilemap; both of which are located in 16k page 5
The tile description area is a contiguous list of tile descriptions starting at the location indicated by bits 5-0 of the value in Nextreg $6F (111) Tile Definitions Base Address.
Each tile description is a 32 byte block of 4-bit values describing the indices of each pixel of a tile in row major order.
The tilemap begins at the location stored in bits 5-0 of Nextreg $6E (110) Tilemap Base Address.
This map either consists of either pairs of tile numbers and tile attributes, or a list of tile numbers. If no attributes are present (bit 5 of Nextreg $6B=1) then the attributes for all tiles come from Nextreg $6C (108) Default Tilemap Attribute.
bits 7-4: palette offset bit 3: mirror X bit 2: mirror Y bit 1: Rotate bit 0: In 256-tile mode ULA over tilemap, in 512-tile mode bit 8 of tile number
Nextreg $1B (27) Clip Window Tilemap
bits 7-0: Coord. of the clip window 1st write = X1 position 2nd write = X2 position 3rd write = Y1 position 4rd write = Y2 position The values are 0,159,0,255 after a Reset Reads do not advance the clip position
Nextreg $2F (47) Tilemap Offset X MSB
bits 7-2: Reserved (0) bits 1-0: MSB X Offset Meaningful Range is 0-319 in 40 char mode, 0-639 in 80 char mode
Nextreg $30 (48) Tilemap Offset X LSB
bits 7-0: LSB X Offset Meaningful range is 0-319 in 40 char mode, 0-639 in 80 char mode
Nextreg $31 (49) Tilemap Offset Y
bits 7-0: Y Offset (0-191)
Nextreg 43 (67) Palette Control
bit 7: '1' to disable palette write auto-increment. bits 6-4: Select palette for reading or writing: 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 bit 3: Select Sprites palette (0 = first palette, 1 = second palette) bit 2: Select Layer 2 palette (0 = first palette, 1 = second palette) bit 1: Select ULA palette (0 = first palette, 1 = second palette) bit 0: Enable Enhanced ULA mode if 1 (0 after a reset)
Nextreg $68 (104) ULA Control
bit 7: 1 to disable ULA output bit 6: 0=select the ULA colour for blending in SLU modes 6 & 7 1=select the ULA/tilemap mix for blending in SLU modes 6 & 7 bits 5-1: Reserved (0) bit 0: 1=enable stencil mode when both the ULA and tilemap are enabled (if either are transparent the result is transparent otherwise the result is a logical AND of both colours)