pinmux
Note that many pin functions of the Duo series are multiplexed. When using applications (such as wiringX, pinpong) to control the functions of each pin, it is important to confirm the current state of the pin to ensure it matches the desired functionality. If it doesn't, you can use the duo-pinmux command to switch it to the desired function.
The pin names for Duo and Duo256M
For Duo pin multiplexing function, please refer to: Duo GPIO Pinout
For Duo256M pin multiplexing function, please refer to: Duo256M GPIO Pinout
| PIN NAME | Pin# | Pin# | PIN NAME |
|---|---|---|---|
| GP0 | 1 | 40 | VBUS |
| GP1 | 2 | 39 | VSYS |
| GND | 3 | 38 | GND |
| GP2 | 4 | 37 | 3V3_EN |
| GP3 | 5 | 36 | 3V3(OUT) |
| GP4 | 6 | 35 | |
| GP5 | 7 | 34 | |
| GND | 8 | 33 | GND |
| GP6 | 9 | 32 | GP27 |
| GP7 | 10 | 31 | GP26 |
| GP8 | 11 | 30 | RUN |
| GP9 | 12 | 29 | GP22 |
| GND | 13 | 28 | GND |
| GP10 | 14 | 27 | GP21 |
| GP11 | 15 | 26 | GP20 |
| GP12 | 16 | 25 | GP19 |
| GP13 | 17 | 24 | GP18 |
| GND | 18 | 23 | GND |
| GP14 | 19 | 22 | GP17 |
| GP15 | 20 | 21 | GP16 |
| GP25 | LED |
The pin names for DuoS
For DuoS pin multiplexing function, please refer to: DuoS GPIO Pinout
Header J3
GPIO on Header J3 use 3.3V logic levels.
| PIN NAME | PIN# | PIN# | PIN NAME |
|---|---|---|---|
| 3V3 | 1 | 2 | VSYS(5V) |
| B20 | 3 | 4 | VSYS(5V) |
| B21 | 5 | 6 | GND |
| B18 | 7 | 8 | A16 |
| GND* | 9 | 10 | A17 |
| B11 | 11 | 12 | B19 |
| B12 | 13 | 14 | GND |
| B22 | 15 | 16 | A20 |
| 3V3 | 17 | 18 | A19 |
| B13 | 19 | 20 | GND |
| B14 | 21 | 22 | A18 |
| B15 | 23 | 24 | B16 |
| GND | 25 | 26 | A28 |
GND*: Pin 9 is a low-level GPIO in the V1.1 version of the hardware, and is GND in the V1.2 version and later.
Header J4
GPIO on Header J4 use 1.8V logic levels.
Most of the pins on this header have dedicated functions, such as MIPI DSI signals, Touch Screen signals, and audio signals. If there is no special requirement, it is not recommended to use the pins on this header as GPIO.
| PIN NAME | PIN# | PIN# | PIN NAME |
|---|---|---|---|
| VSYS(5V) | 52 | 51 | AUDIO_OUT_R |
| B1 | 50 | 49 | AUDIO_OUT_L |
| B2 | 48 | 47 | AUDIO_IN_R |
| B3 | 46 | 45 | AUDIO_IN_L |
| E2 | 44 | 43 | 3V3 |
| E1 | 42 | 41 | C18 |
| E0 | 40 | 39 | C19 |
| GND | 38 | 37 | GND |
| C20 | 36 | 35 | C16 |
| C21 | 34 | 33 | C17 |
| GND | 32 | 31 | GND |
| C14 | 30 | 29 | C12 |
| C15 | 28 | 27 | C13 |
Pin multiplexing configuration
The following uses Duo as an example to introduce how to configure pin multiplexing.
Executing the duo-pinmux command directly allows you to view the usage instructions
[root@milkv-duo]~# duo-pinmux
pinmux for duo
duo-pinmux -p <== List all pins
duo-pinmux -l <== List all pins and its func
duo-pinmux -r pin <== Get func from pin
duo-pinmux -w pin/func <== Set func to pin
To check the multiplexing status of a specific pin, such as pin 1 on Duo, you need to know the name of that pin. As indicated in the diagram above, the name of pin 1 is GP0. To view its multiplexing status, use the command duo-pinmux -r followed by the pin name
[root@milkv-duo]~# duo-pinmux -r GP0
GP0 function:
[ ] JTAG_TDI
[ ] UART1_TX
[ ] UART2_TX
[ ] GP0
[v] IIC0_SCL
[ ] WG0_D0
[ ] DBG_10
You can see that the current function is IIC0_SCL, indicating it is configured as the SCL pin for I2C0. If you want to configure pin 1 as a GPIO, you can use the following command: duo-pinmux -w pin_name/function
duo-pinmux -w GP0/GP0
Now, check the multiplexing status of the pin again
[root@milkv-duo]~# duo-pinmux -r GP0
GP0 function:
[ ] JTAG_TDI
[ ] UART1_TX
[ ] UART2_TX
[v] GP0
[ ] IIC0_SCL
[ ] WG0_D0
[ ] DBG_10
You can see that it has been configured as GP0 now
Similarly, to configure pin 1 as the TX pin for UART1, you need to execute
duo-pinmux -w GP0/UART1_TX
Check the multiplexing status
[root@milkv-duo]~# duo-pinmux -r GP0
GP0 function:
[ ] JTAG_TDI
[v] UART1_TX
[ ] UART2_TX
[ ] GP0
[ ] IIC0_SCL
[ ] WG0_D0
[ ] DBG_10
It meets the expectation
