Error initialising PWM on pin?

ROCK 4 Series
1

  1. I have already installed libmraa.

  2. I have already settup /boot/hw_intfc.conf
    intfc:pwm0=on
    intfc:pwm1=on

  3. reboot ROCK pi 4 SE several times.

  4. Testing pwm.c in /usr/local/share/mraa/examples/pwm.c and compile it with:
    sudo gcc -o pwm pwm.c -lmraa
    sudo ./pwm
    Failed to initialize PWM

  5. Trying to using python to test.

    import mraa
    import time

x = mraa.Pwm(11)

x.period_us(700)

x.enable(True)

value = 0.0

while True:
x.write(value)

 time.sleep(0.05)

 value += 0.01

 if value >= 1:
     value = 0.0

but no luck …

image
image1851×639 51.3 KB

Is there something wrong with the low level library?

2

[SOLVED] by flashing a new image: rockpi-4b-debian-bullseye-xfce4-arm64-20221018-1430-gpt.img.xz
and then connect to wifi, update and upgrade os, configure hw_intfc.conf and reboot again, test it without any trouble…

3

Refer to : https://iotdk.intel.com/docs/master/mraa/python/example.html#pwm

4

I get the same problem with a similar image: rockpi-4b-debian-bullseye-xfce4-arm64-20221109-1447-gpt.img.xz (I can’t find the quoted image anymore, but this is a bit later)
Any ideas?

5

[SOLVED}
You have to run the mraa/examples/c in root as root! This is rather inconvenient, as my application will have to run as root too in order to call call mraa code. Unless there is a method of running them from home/… ?

6

I have already added rock user to root group, so that is may not the privilleges problem. but it works right now, I can adjust my fan speed anyway. thanks for your tips LoL.