Create PWM sequence using TIMER/GPIOTE/PPI

[Ian]

Due to the PWM driver having intermittent issues we had to replace it with a TIMER/PPI/GPIOTE setup. The PWM is working great in this way, but now I'd like to have one of the TIMER compare values iterate through a sequence without using interrupts. I'm trying to keep the power draw to a minimum. Is there a way to do this, perhaps with EasyDMA or another method?

Thanks, Ian

[Stefan Birnir Sverrisson]

Hi Ian

What intermittent issues are you having with the PWM driver?

There are two pwm libraries available in the SDK, one is the pwm_library, which uses TIMER+GPIOTE+PPI. Another library is the low_power_pwm, which uses application timers and RTC1 in the background. It is therefore not very accurate but can control e.g. LEDs etc. There are examples in SDK 11.0.0 that use both those libraries.

[Ian]

Hi Stefan,

The intermittent issues caused the PWM to jump to 100% occasionally when using the soft device. The issue was brought up with Martin and Ole previously.

I ended up using an app timer to do the PWM in a similar way as low_power_pwm does, as it did not need to be accurate. I was hoping to avoid using interrupts but current consumption of the LF clock is so low that this method is adequate.

Thanks for the help, Ian