Can't reach desired μA values on nRF52833 on power saving modes

[IoTMAN]

Hello, 

I have a custom board that has an nRF52833 SoC. I'm measuring current consumption with nRF Power Profiler Kit 2. All my tries of any kind of power saving including system off ended up in ~2mA current consumption at 3.3V supply voltage. 

I've tried many power saving examples such as system_off example (I'm using nRF Connect SDK), turned off  all peripherals in the devicetree and tried many solutions I've found online. I've also tried using/and not using DCDC regulator after making appropriate hardware modifications but all my tries were in vain. I am using no LEDs or any unnecessary power consuming device. My current rates drop as I run system_off example but it ends up in ~2mA but testing the same solutions, I could read μA values in my nRF52840Dongle. 

Measured my custom board's consumption without the SoC on the board and it was around 0.5mA, so I'm guessing I still can't enter power saving mode, since chip seems to consume ~1.5mA. 

Am I missing something? Maybe an external hardware configuration that I'm not implementing or some special config that should specifically be entered for nRF52833?

Thank you for your help. 

[Kazi Afroza Sultana]

Hello,

Can you share your schematic design of hardware?

You can read out the GPIO registers to check if any of the GPIOs are configured as output. If there are any GPIOs pin are on as output, it may power other peripherals of the board. 

This is the command of checking this:

$nrfjprog --memrd 0x50000700 --n 0x80 && nrfjprog --memrd 0x50000A00 --n 0x40

Here is previous case you can look at for reference (https://devzone.nordicsemi.com/f/nordic-q-a/94117/nrf52840-dongle-and-blinky-example-using-gpio-0-31-draws-8ma/398294). 

Thanks.

Best Regards,

Kazi Afroza Sultana

[Learner]

Good Morning,

I am trying to reduce the power consumption of our device (nrF52833 SoC) to the bear minimum by sending into shutdown mode. I am wondering whether you can help me out.

Kazi Afroza Sultana said:

$nrfjprog --memrd 0x50000700 --n 0x80 && nrfjprog --memrd 0x50000A00 --n 0x40

1- When I first tried to use the nrfjprog command to read the status of my GPIO pins I found my application stops                   running. I did, however, get a dump of the GPIOs statuses as shown below,

C:\WINDOWS\system32>nrfjprog --memrd 0x50000700 --n 0x80 && nrfjprog --memrd 0x50000A00 --n 0x40
0x50000700: 00000002 00000002 0000060C 00000001 |................|
0x50000710: 00000002 00000003 00000002 00000002 |................|
0x50000720: 00000002 00000003 00000002 00000003 |................|
0x50000730: 00000002 00000002 00000002 00000003 |................|
0x50000740: 00000002 00000000 00000002 00000002 |................|
0x50000750: 00000003 00000003 00000000 00000001 |................|
0x50000760: 00000002 00000002 00000002 00000002 |................|
0x50000770: 0000060C 0000000C 00000000 00000002 |................|
0x50000A00: 00000002 00000002 00000002 00000002 |................|
0x50000A10: 00000002 00000002 00000002 00000002 |................|
0x50000A20: 00000002 00000000 00000000 00000000 |................|
0x50000A30: 00000000 00000000 00000000 00000000 |................|

I am not sure whether I can trust the information given above since the nrfjprog command interfered with the normal operation of the device.

2- On subsequent tries I get this error message,

 C:\WINDOWS\system32>nrfjprog --memrd 0x50000700 --n 0x80 && nrfjprog --memrd 0x50000A00 --n 0x28
ERROR: The operation attempted is unavailable due to readback protection in
ERROR: your device. Please use --recover to unlock the device.
NOTE: For additional output, try running again with logging enabled (--log).
NOTE: Any generated log error messages will be displayed.

Any comments?

Note, this is my hardware setup,

Windows laptop connected through USB to nRF52833-DK board in turn connected to the target board built around nRF52833 SoC.

Kind regards

Mohamed.

[Kazi Afroza Sultana]

Hello Mohamed,

Can you please open a new ticket describing the issues elaborately so I will reply there.  

Thanks.

BR
Kazi

[Learner]

OK, will do.