GPIO A23 and A25 not working as expected #461

New issue

Open

opened 2026-03-03 03:11:20 -05:00 by sandreas · 0 comments

sandreas commented

2026-03-03 03:11:20 -05:00

(Migrated from github.com)

Hello,

I'm trying to use some push buttons on the LicheeRV Nano (Wifi version). The interesting thing is, that while GPIO A22 and A24 are working like expected, A23 and A25 are NOT working. I double checked the wiring with my multimeter, which is:

3.3V => Push-Button => GPIO PIN

The multimeter shows that the connection is OK (see below for a photo of the breadboard).

My Questions:

Is there anything that I'm missing here? (e.g. Reserved GPIO)
Which GPIOs would be free to use for push buttons by default?
If there are no GPIO Buttons free to use, which ones could be freed by disabling other unwanted features (e.g. Serial port etc.)

Here are some commands that I used to check for the PINS.

A23 and A25 NOT WORKING
The watch command is always showing 1 as a value, regardless whether the buttons are pressed or not.

# A23
devmem 0x0300105C b 0x03
echo 503 > /sys/class/gpio/export
watch -n 1 -t cat /sys/class/gpio/gpio503/value

# A25
devmem 0x03001054 b 0x03
echo 505 > /sys/class/gpio/export
watch -n 1 -t cat /sys/class/gpio/gpio505/value

A22 and A24 working as expected
The watch command shows 0 as soon as I push the regarding button and flips back to 1 when I release it (works like expected)

# A22
devmem 0x03001050 b 0x03
echo 502 > /sys/class/gpio/export
watch -n 1 -t cat /sys/class/gpio/gpio502/value

# A24
devmem 0x03001060 b 0x03
echo 504 > /sys/class/gpio/export
watch -n 1 -t cat /sys/class/gpio/gpio504/value

Here is a photo of my breadboard:

Hello, I'm trying to use some push buttons on the LicheeRV Nano (Wifi version). The interesting thing is, that while GPIO A22 and A24 are working like expected, A23 and A25 are NOT working. I double checked the wiring with my multimeter, which is: ``` 3.3V => Push-Button => GPIO PIN ``` The multimeter shows that the connection is OK (see below for a photo of the breadboard). My Questions: - Is there anything that I'm missing here? (e.g. Reserved GPIO) - Which GPIOs would be free to use for push buttons by default? - If there are no GPIO Buttons free to use, which ones could be freed by disabling other unwanted features (e.g. Serial port etc.) Here are some commands that I used to check for the PINS. **`A23` and `A25` NOT WORKING** The watch command is always showing `1` as a value, regardless whether the buttons are pressed or not. ``` # A23 devmem 0x0300105C b 0x03 echo 503 > /sys/class/gpio/export watch -n 1 -t cat /sys/class/gpio/gpio503/value # A25 devmem 0x03001054 b 0x03 echo 505 > /sys/class/gpio/export watch -n 1 -t cat /sys/class/gpio/gpio505/value ``` **`A22` and `A24` working as expected** The watch command shows `0` as soon as I push the regarding button and flips back to `1` when I release it (works like expected) ``` # A22 devmem 0x03001050 b 0x03 echo 502 > /sys/class/gpio/export watch -n 1 -t cat /sys/class/gpio/gpio502/value # A24 devmem 0x03001060 b 0x03 echo 504 > /sys/class/gpio/export watch -n 1 -t cat /sys/class/gpio/gpio504/value ``` Here is a photo of my breadboard: ![Image](https://github.com/user-attachments/assets/939c4d84-eded-4802-a904-3058c80c0da8)