PPK: nRF Connect GUI hangs when I change voltage regulator level

[pieterc]

Hi everyone,

I am using the PPK to supply 3V to an external device and measure the current consumption.

When I start nrF Connect, connect to the PPK and change the Voltage Regulator value (from default 2.1V to 3V) the GUI hangs. The scrolling graph from right to left stops. When I click on the Power OFF button, it is reported that "PPK command failed" in the Log window.

I can measure that the output voltage did change to 3V (2.912V actually). If I select "Close Device" and reopen the device, it is reported "Corrupt data detected, please check connection to PPK".

If I close nRF Connect and reopen it and connect to the PPK then the Voltage Regulator output is 3V (2.912V actually)

Info that may help:

1. nrF Connect v3.3.0

2. SEGGER version: J-Link OB-SAM3U128-V2-NordicSemi compiled Jan 7 2019 14:07:15

3. Device s/n 000682661360 (PCA10040)

3. SW2 (DUT select) set to External

4. SW4 (Power select) set to Reg.

5. COM slide switch set to DK

Any tips / hints would be much appreciated.

Thanks in advance,

Pieter

https://piconomix.com

[Jørgen Holmefjord]

Hi,

Since you have set the COM switch to DK, I assume that you have connected the PPK on top of the DK, and use the power from the DK to supply the PPK and DUT? Please have a look at this answer.

Best regards,
Jørgen

[Jørgen Holmefjord]

The main problem with using the reg mode is that the measurements will not be correct, as mentioned in the documentation:

"Make sure that the PPK regulator voltage exactly matches the nRF5 DK voltage. Otherwise, current leakage may occur and lead to erroneous current readings."

I think that the issue you are seeing is related to the voltage of the regulator getting too low for the debug-chip on the DK to be able to communicate with the nRF on the PPK (since this will be powered with the regulator voltage). The J-Link OB debugger on the DK does not support level shifting, meaning it will only work with devices running on 3 V.

[Jørgen Holmefjord]

Did you read my previous comments? Are you powering the PPK externally? It will not work when connected on top of DK, or with the DK debugger.

[sirio]

I did, thank you.

This is how I am connected:

1. host computer -(USB)-> nRF52-DK (SB9 is cut as per PPK manual)

2. PPK mounted of top of nRF52-DK:

  - Power Select (SW4): DK

  - DUT Select (SW2): External

3. Voltmeter connected between pins of External DUT (P16)

- The Power Profiler App connects to the PPK and initializes it correctly.

- Only 2.87v is measured at External DUT (p16).

- I can change the Voltage Regulator control to any value, but p16 remains 2.87v

- Power ON/OFF control works (0v on OFF), but when returning to ON p16 only has 2.87v

- I can connect and disconnect, but p16 only has 2.87v

- This behavior is the same on Windows and on MacOS (tested this also today). MacOS version data:

# nRFConnect System Report - 2020-05-06T14-58-49.119Z

- System:     Apple Inc. MacBookPro11,5
- BIOS:       Apple Inc. 
- CPU:        1 x Intel® Core™ i7-4870HQ 2.50 GHz 8 cores (4 physical)
- Memory:     660 MB free of 16 GB total
- Filesystem: /dev/disk1s1 (HFS) 931.6 GB 49.6% used

- OS:         Mac OS X (10.14.6) darwin x64

- Versions
    - kernel: 18.7.0
    - git: 2.20.1
    - node: 12.0.0
    - python: 2.7.16
    - python3: 

As a test measure, is there a way to connect with a UART and manually set the voltage on the PPK?

That way I can verify that the PPK is operating properly.

[Jørgen Holmefjord]

If the Power Select (SW4) is set to DK, the regulators will not be used at all, which is why you are not seeing any change in the voltage.

If you set the switch to Reg, you should be able to use the voltage regulator with the latest release (2.3.1):

[anusha_14]

I am facing the same issue with power profiler 2.3.1 with this same setup. Also, I cannot set the regulator voltage to exactly 3000 mV. It either goes to 2996m V or 3005 mV. How can I set the voltage to exactly 3000 mV?

[Jørgen Holmefjord]

I'm not able to reproduce this on my setup. Are you using Windows, or another OS?

After you set the voltage close to 3000 mV, you can use the arrow keys on the keyboard to single step to the desired voltage. I do not think that the regulator has that high accuracy that it does matter a lot though.