Disabling/enabling peripherals at runtime on nrf91

[RonanB96]

Are there any examples for disabling/enabling peripherals at runtime for low power purposes on the nRF91 on ncs v1.0.0?

I've seen these threads but they didn't have the info I wanted

https://devzone.nordicsemi.com/nordic/cellular-iot-guides/b/hardware-design/posts/measuring-psm-idle-current-on-the-nrf91-dk

https://devzone.nordicsemi.com/f/nordic-q-a/43728/nrf9160-low-power-example/189878#189878

I wish to disable I2C and UART before going to sleep with just the RTC enabled and wakeup after a timeout or interrupt on a single pin and enable those peripherals again

[Hakon]

The following two lines shoud do it

disable_i2c();
NRF_UARTE0_NS->ENABLE = 0;

You can change NRF_UARTE0_NS to whichever UART device you want to disable.

[RonanB96]

Sorry about the delay, I have only got around to testing this now. I have tested disabling the UART and I2C successfully but I have three more questions.

• With an interrupt enabled on one pin I am seeing an increase of 45uA, is there a way to decrease this? The pin is configured with the following settings: GPIO_INT | GPIO_INT_EDGE | GPIO_INT_ACTIVE_HIGH | GPIO_INT_DOUBLE_EDGE | GPIO_INT_DEBOUNCE
• Is there a common place where I can reenable my peripherals when leaving k_cpu_idle? I either leave idle from an interrupt or from a k_timer. I am not calling k_cpu_idle myself in any of my loops, just when all of my threads and inactive it is called.
• I didn't find a function called disable_i2c() anywhere, where is it defined? I got around it by setting NRF_TWIM0_NS->ENABLE = 0

[Hakon]

You should post this question separately in order to get better support. It is somewhat unrelated to the original question.

[RonanB96]

I was able to bring the current back down by calling gpio_disable_callback on the pin and enable a basic interrupt on the pin using the nrf_gpio_cfg_sense_set. I have opened up another ticket about the idle question