Using RPI3B+. I already use GPIO 12 (the other PWM channel 0 pin) for a ledstrip.

[Question: Can I use GPIO 18 on a different frequency, or do GPIO 12 and GPIO 18 share the same frequency when used as pwm since they are the same channel?]

1 Answer 1


When set to PWM mode (i.e. internally connected to the PWM hardware) GPIO 12 and GPIO 18 are the same point electrically. Exactly the same signal will be transmitted to both GPIO.

  • So, RPI offers 2 PWM channels with both 2 pins. But you can only use one channel at a time, if thats right. Do you know why the RPI has 4 pins hardware PWM capable when you can actually only use 1?
    – aWiseMan
    May 6, 2021 at 9:17
  • Not quite. There are two channels. 0 is connected to 12/18. 1 is connected to 13/19. You can use both channels with different settings so 2 (not 1) can be used at a time. As to why 12 and 18 that's just for convenience. For some people the wiring might dictate that its better to use one rather than the other. You could ask why more than one ground pin, again it's for convenience.
    – joan
    May 6, 2021 at 9:27
  • Ah ok, that makes more sense. I know its for convience but 4 different pins for 1 signal would have been a bit too convenient imo. But I thought only one channel could be used at a time.
    – aWiseMan
    May 6, 2021 at 9:59

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