Tilemap
Contents
Tilemap
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 Tilemap Control Register ($6B / 107)
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
Tile Description
The tile description area is a contiguous list of tile descriptions starting at the location indicated by bits 5-0 of the value in Tile Definitions Base Address Register ($6F / 111).
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.
Tilemap
The tilemap begins at the location stored in bits 5-0 of Tilemap Base Address Register ($6E / 110).
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 Default Tilemap Attribute Register ($6C / 108).
Tile 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
Additional Registers
Clip Window Tilemap Register ($1B / 27)
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
Tilemap Offset X MSB Register ($2F / 47)
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
Tilemap Offset X LSB Register ($30 / 48)
bits 7-0: LSB X Offset Meaningful range is 0-319 in 40 char mode, 0-639 in 80 char mode
Tilemap Offset Y Register ($31 / 49)
bits 7-0: Y Offset (0-255)
Enhanced ULA Control Register ($43 / 67)
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)
ULA Control Register ($68 / 104)
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)