nRF53 low-power guidance

[Chasen]

Hello,

I am looking for some guidance in getting my application in a low power state. I originally came across the post here. I could not get this example working, and it appears to be because most of the power management hooks are handled automatically as described here. I have gone through my application and stopped all threads, disabled the USB and BLE peripheral, and setting IO to minimize leakage. That all being said, lowest I have been able to get the board to operate at is 1.4mA/ at 4 volts. I have a couple of questions

1. I am disabling the BLE by calling the following. Is this sufficient or is there additional steps I need to take
   
   1. bt_le_adv_stop();
      bt_disable();
2. likewise, I am disabling the USB by calling the following.
   1. usb_disable()
3. When I am done with all my application housekeeping, I call k_cpu_idle() then have the system loop on a k_sleep(K_MSEC(10000));
   
4. I have a qspi peripheral that is disabled in low power mode, but a couple of pins are still sitting at 4v(csn and qspi3). Can I manually toggle these pins when I enter low power mode.
5. In general can I inspect peripherals such as usb/pwm/ble and query for there power state?

Lastly I am currently using SDK v2.5.3

Thank you in advance!

[Kenneth]

Hello,

I suggest to check out: https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/test_and_optimize/optimizing/power_general.html 

To measure correctly power consumption you should power cycle the board to ensure it exit debug mode after programming.

I notice you refer to 4V several times, make sure that VDD is between 1.7-3.6V, as specified here:
https://docs.nordicsemi.com/bundle/ps_nrf5340/page/chapters/recommended_op_conditions/doc/recommended_op_conditions.html 

If you are feeding voltage through VDDH, then the maximum is 5.5V in the above link.

The I/O pins voltage must not exceed VDD+0.3V (or max 3.9V if using VDDH).

Kenneth

[Chasen]

Hello Kenneth,

Thank you for the quick reply and the resource. Thank you for the heads up on the supply voltages. The rest of the system is running at 3v3, I am just running the nrf53 directly from the battery so I can turn the rest of the system off. I will take a look at the power_general link you sent and see what I come up with.

Thank you again!