Palette Value Register | $41 | true | true | Use to set/read 8-bit colours of the ULANext palette. |
Enhanced ULA Ink Color Mask | $42 | true | true | Specifies mask to extract ink colour from attribute cell value in ULANext mode. |
Enhanced ULA Control Register | $43 | true | true | Enables or disables Enhanced ULA interpretation of attribute values and toggles active palette. |
Enhanced ULA Palette Extension | $44 | true | true | Use to set 9-bit (2-byte) colours of the Enhanced ULA palette, or to read second byte of colour. |
Transparency colour fallback Register | $4A | true | true | 8-bit colour to be used when all layers contain transparent pixel. |
Sprites Transparency Index Register | $4B | true | true | Index into sprite palette (of "transparent" colour). |
Tilemap Transparency Index Register | $4C | true | true | Index into Tilemap palette (of "transparent" colour). |
Memory management slot 0 bank | $50 | true | true | Selects the 8k-bank stored in 8k-slot 0 (see Memory map). |
Memory management slot 1 bank | $51 | true | true | Selects the 8k-bank stored in 8k-slot 1 (see Memory map). |
Memory management slot 2 bank | $52 | true | true | Selects the 8k-bank stored in 8k-slot 2 (see Memory map). |
Memory management slot 3 bank | $53 | true | true | Selects the 8k-bank stored in 8k-slot 3 (see Memory map). |
Memory management slot 4 bank | $54 | true | true | Selects the 8k-bank stored in 8k-slot 4 (see Memory map). |
Memory management slot 5 bank | $55 | true | true | Selects the 8k-bank stored in 8k-slot 5 (see Memory map). |
Memory management slot 6 bank | $56 | true | true | Selects the 8k-bank stored in 8k-slot 6 (see Memory map). |
Memory management slot 7 bank | $57 | true | true | Selects the 8k-bank stored in 8k-slot 7 (see Memory map). |
Copper Data | $60 | false | true | Used to upload code to the Copper. |
Copper Control Low Byte | $61 | true | true | Holds low byte of Copper control bits. |
Copper Control High Byte | $62 | true | true | Holds high byte of Copper control flags. |
Copper Data 16-bit Write Register | $63 | false | true | Used to upload code to the Copper. |
Vertical Video Line Offset Register | $64 | true | true | Offset numbering of raster lines in copper/interrupt/active register |
ULA Control Register | $68 | true | true | Disable ULA, controls ULA mixing/blending, enable ULA+ |
Display Control 1 Register | $69 | true | true | Layer2, ULA shadow, Timex $FF port |
LoRes Control Register | $6A | true | true | LoRes Radastan mode |
Tilemap Control Register | $6B | true | true | Controls Tilemap mode. |
Default Tilemap Attribute Register | $6C | true | true | Default tile attribute for 8-bit only maps. |
Tilemap Base Address Register | $6E | true | true | Base address of the 40x32 or 80x32 tile map (similar to text-mode of other computers). |
Tile Definitions Base Address Register | $6F | true | true | Base address of the tiles' graphics. |
Layer 2 Control Register | $70 | true | true | Layer 2 resolution, palette offset |
Layer 2 X Offset MSB Register | $71 | true | true | Sets the pixel offset used for drawing Layer 2 graphics on the screen. |
Sprite port-mirror Attribute 0 (with INC) Register | $75 | false | true | Same as Sprite port-mirror Attribute 0 Register ($35) (write first byte of sprite-attributes), plus increments Sprite port-mirror Index Register ($34) |
Sprite port-mirror Attribute 1 (with INC) Register | $76 | false | true | Same as Sprite port-mirror Attribute 1 Register ($36) (write second byte of sprite-attributes), plus increments Sprite port-mirror Index Register ($34) |
Sprite port-mirror Attribute 2 (with INC) Register | $77 | false | true | Same as Sprite port-mirror Attribute 2 Register ($37) (write third byte of sprite-attributes), plus increments Sprite port-mirror Index Register ($34) |
Sprite port-mirror Attribute 3 (with INC) Register | $78 | false | true | Same as Sprite port-mirror Attribute 3 Register ($38) (write fourth byte of sprite-attributes), plus increments Sprite port-mirror Index Register ($34) |
Sprite port-mirror Attribute 4 (with INC) Register | $79 | false | true | The same as Sprite port-mirror Attribute 4 Register ($39) (write fifth byte of sprite-attributes), plus increments Sprite port-mirror Index Register ($34) |
User Storage 0 Register | $7F | true | true | 8-bit storage for user |
Expansion Bus Enable Register | $80 | true | true | Expansion bus enable/config |
Expansion Bus Control Register | $81 | true | true | Expansion bus controls |
Internal Port Decoding b0-7 Register | $82 | true | true | Enabling internal ports decoding |
Internal Port Decoding b8-15 Register | $83 | true | true | Enabling internal ports decoding |
Internal Port Decoding b16-23 Register | $84 | true | true | Enabling internal ports decoding |
Internal Port Decoding b24-31 Register | $85 | true | true | Enabling internal ports decoding |
Expansion Bus Decoding b0-7 Register | $86 | true | true | When expansion bus is enabled: Internal ports decoding mask |
Expansion Bus Decoding b8-15 Register | $87 | true | true | When expansion bus is enabled: Internal ports decoding mask |
Expansion Bus Decoding b16-23 Register | $88 | true | true | When expansion bus is enabled: Internal ports decoding mask |
Expansion Bus Decoding b24-31 Register | $89 | true | true | When expansion bus is enabled: Internal ports decoding mask |
Expansion Bus I/O Propagate Register | $8A | true | true | Monitoring internal I/O or adding external keyboard |
Alternate ROM | $8C | true | true | Enable alternate ROM or lock 48k ROM |
Memory Mapping Register | $8E | true | true | Control classic Spectrum memory mapping |
Pi GPIO Output Enable Register | $90-$93 | true | true | Enables GPIO pins output |
Pi GPIO Register | $98-$9B | true | true | GPIO pins mapped to Next Register |