Semantic search
| Number | Readable | Writable | Description | |
|---|---|---|---|---|
| Internal Port Decoding b8-15 Register | $83 | Yes | Yes | Enabling internal ports decoding |
| Internal Port Decoding b16-23 Register | $84 | Yes | Yes | Enabling internal ports decoding |
| Internal Port Decoding b24-31 Register | $85 | Yes | Yes | Enabling internal ports decoding |
| Expansion Bus Decoding b0-7 Register | $86 | Yes | Yes | When expansion bus is enabled: Internal ports decoding mask |
| Expansion Bus Decoding b8-15 Register | $87 | Yes | Yes | When expansion bus is enabled: Internal ports decoding mask |
| Expansion Bus Decoding b16-23 Register | $88 | Yes | Yes | When expansion bus is enabled: Internal ports decoding mask |
| Expansion Bus Decoding b24-31 Register | $89 | Yes | Yes | When expansion bus is enabled: Internal ports decoding mask |
| Expansion Bus I/O Propagate Register | $8A | Yes | Yes | Monitoring internal I/O or adding external keyboard |
| Alternate ROM | $8C | Yes | Yes | Enable alternate ROM or lock 48k ROM |
| Memory Mapping Register | $8E | Yes | Yes | Control classic Spectrum memory mapping |
| Pi GPIO Output Enable Register | $90-$93 | Yes | Yes | Enables GPIO pins output |
| Pi GPIO Register | $98-$9B | Yes | Yes | GPIO pins mapped to Next Register |
| Pi Peripheral Enable Register | $A0 | Yes | Yes | Enable Pi peripherals: UART, Pi hats, I2C, SPI |
| Pi I2S Audio Control Register | $A2 | Yes | Yes | Pi I2S controls |
| Pi I2S Clock Divide Register | $A3 | Yes | Yes | |
| ESP WiFi GPIO Output Register | $A8 | Yes | Yes | ESP WiFi GPIO Output |
| ESP WiFi GPIO Register | $A9 | Yes | Yes | ESP WiFi GPIO Read/Write |
| Extended Keys 0 Register | $B0 | Yes | No | Read Next keyboard compound keys separately |
| Extended Keys 1 Register | $B1 | Yes | No | Read Next keyboard compound keys separately |
| DivMMC Trap Enable 1 Register | $B2 | Yes | Yes | |
| DivMMC Trap Enable 2 Register | $B4 | Yes | Yes | |
| Debug LED Control Register | $FF | No | Yes | Turns debug LEDs on and off on TBBlue implementations that have them. |