Pi Peripheral Enable Register
From SpecNext official Wiki
| Number | $A0 |
|---|---|
| Readable | Yes |
| Writable | Yes |
| Short Description | Enable Pi peripherals: UART, Pi hats, I2C, SPI |
| Bit | Description |
|---|---|
| 7-6 | Reserved, must be 0 |
| 5 | Enable UART on GPIO 14,15 (overrides GPIO) (soft reset = 0) * |
| 4 | 0 to connect Rx to GPIO 15, Tx to GPIO 14 (for comm with Pi hats) (soft reset = 0)
1 to connect Rx to GPIO 14, Tx to GPIO 15 (for comm with Pi) |
| 3 | Enable I2C on GPIO 2,3 (overrides GPIO) (soft reset = 0) |
| 2-1 | Reserved, must be 0 |
| 0 | Enable SPI on GPIO 7,8,9,10,11 (overrides GPIO) (soft reset = 0) |
* GPIO 16,17 will function as rtr_n and cts_n if the uart is in hw flow control mode
(note: Next registers with number higher than $7F are inaccessible from Copper code)