Write pwm export() failed for id xx "with open gpiochip0"

Question

Write pwm export() failed for id xx "with open gpiochip0"

Closed this issue 3 months ago · 4 comments

Trying to write pwm to a LedDriver with a raspberry pi 4 (fresh install of raspbian) fives the error export() failed for id 26 "with open gpiochip0" (trying to use the pin "37" that is actually GPIO 26).
This error is actually new in v2.3.0 of gobot (I just reverted to 2.2 and everything works fine).

Answer 1 · 2024-03-14T18:23:03.000Z

Hi @idalmasso , thanks for finding and report this issue. I will have a look in the next few days.

Answer 2 · 2024-03-17T17:30:57.000Z

Hi @idalmasso , the PWM usage has changed a bit since 2.3.0.
Until 2.2.0 the pi-blaster was used by default. Now the internal PWMs are used by default and the usage of pi-blaster must be forced by "adaptors.WithPWMUsePiBlaster()". I missed to add this to the migration guide, but it is described in the README.

If it will not work , please can you provide your program or at least the part for creating the raspi-adaptor and the lines which creates the error output.

Thanks Thomas

Answer 3 · 2024-03-18T10:53:13.000Z

Hello @gen2thomas , thanks for your answer. Yes, I just retried with the WithPWMUsePiBlaster and it seems to be working fine, sorry I had to improve my RTFM capabilities, sorry to have made you lose time!

Answer 4 · 2024-03-18T17:05:47.000Z

You are welcome, good to hear that it's working now.