Fixed issue where metadata would come with garbage

[Tjoms99]

Investigated the PR/issue discussed here #49.

Turns out not properly exiting a program running the PPK2 influences the next PPK2 session. Setting up the metadata the first time will throw an exception due to the garbage data (from the previous session) that comes a long with it. Physically turning the PPK2 on and off using the switch resolves this issue, but that’s inconvenient to do every time; So I’ve added a software fix here :)

To reproduce the issue and showcase the fix

1. Connect the PPK2 via USB

2. Open a terminal and run the example

python3 examples/example_measure_mw.py

3. Terminate the program (2x)

ctrl + c

4. Run the example again and you'll probably see this in the terminal

Attempt 1/2 - Failed to get valid PPK2 metadata: Could not retrieve valid metadata from the device.
Attempt 2/2 - Got metadata from PPK2
Initialized Power Profiler

This is where the UnicodeDecodeError would previously be triggered

[RmThrt]

Thanks for the fix, it helped to figure out the way my test work! Good fix for me :)

[MrKevinWeiss]

Also tested and it works for me!

[MrKevinWeiss]

This is on 4.2.0 and 4.2.1 fw.

[mstixenberger]

works fine, thank you!

[bobatsar]

Works also on my side. @wlgrd is it possible to merge it into master?

[tphillips-ict]

+1 Can we merge this? Running into the same issue.

Is this project still actively maintained?

[MrKevinWeiss]

A few small things, but at least now we can move!

[Tjoms99]

Did another pass on this locally and verified it against a connected PPK2.

A couple of extra things came up while testing/integrating this in other code using the API:

• get_modifiers() is now tightened up so it either succeeds or raises, instead of returning a mixed True / None
• added return type hints in ppk2_api.py for the main API methods so the return contracts are a bit clearer
• fixed the compatibility issue in src/power_profiler.py where get_samples() was still treated like a flat list instead of (samples, raw_digital)

I also removed the library-side logger usage that was ending up affecting my main application logger outside of ppk2. Hard failures now just raise instead of log-and-continue.

Verified by running:
python3 examples/example_measure_mw.py

This still works on my side with a connected PPK2 (/dev/ttyACM0) and streams measurements as expected. How does it look on your end?

[MrKevinWeiss]

Just got back from vacation, I will try to find some time either today or tomorrow for testing and reviewing!

[MrKevinWeiss]

oh 3 weeks old... I guess that slipped through the cracks 🫤

[MrKevinWeiss]

I tested with python3.13 but needed a change...

manual testing results with "fresh" ppk

(.venv) weiss@lobaro-laptop-kw:~/repos/ppk2-api-python$ python examples/example_measure_mw.py
Press Enter to exit...
PPK2 devices found: [('/dev/ttyACM0', 'D06D19AF')]
[('/dev/ttyACM0', 'D06D19AF')]
Connecting to /dev/ttyACM0
Initialized Power Profiler
139.58 mW, Avg: 139.58 mW
27.09 mW, Avg: 83.34 mW
26.72 mW, Avg: 64.46 mW
26.66 mW, Avg: 55.01 mW
26.45 mW, Avg: 49.30 mW
26.29 mW, Avg: 45.47 mW
26.24 mW, Avg: 42.72 mW
26.17 mW, Avg: 40.65 mW
26.04 mW, Avg: 39.03 mW
26.02 mW, Avg: 37.73 mW
25.99 mW, Avg: 36.66 mW
25.95 mW, Avg: 35.77 mW
25.9 mW, Avg: 35.01 mW
25.83 mW, Avg: 34.35 mW
26.51 mW, Avg: 33.83 mW
26.94 mW, Avg: 33.40 mW
26.71 mW, Avg: 33.01 mW
27.01 mW, Avg: 32.67 mW
27.01 mW, Avg: 32.37 mW
26.99 mW, Avg: 32.11 mW
27.43 mW, Avg: 31.88 mW
27.78 mW, Avg: 31.70 mW
30.21 mW, Avg: 31.63 mW

28.85 mW, Avg: 31.52 mW
(.venv) weiss@lobaro-laptop-kw:~/repos/ppk2-api-python$ python examples/example_measure_mw.py
Press Enter to exit...
PPK2 devices found: [('/dev/ttyACM0', 'D06D19AF')]
[('/dev/ttyACM0', 'D06D19AF')]
Connecting to /dev/ttyACM0
Initialized Power Profiler
155.98 mW, Avg: 155.98 mW
26.94 mW, Avg: 91.46 mW
26.68 mW, Avg: 69.87 mW
26.61 mW, Avg: 59.05 mW
26.38 mW, Avg: 52.52 mW
26.22 mW, Avg: 48.13 mW
26.16 mW, Avg: 45.00 mW
26.09 mW, Avg: 42.63 mW
26.09 mW, Avg: 40.79 mW
25.98 mW, Avg: 39.31 mW
25.96 mW, Avg: 38.10 mW
25.92 mW, Avg: 37.08 mW
25.89 mW, Avg: 36.22 mW
25.84 mW, Avg: 35.48 mW
25.84 mW, Avg: 34.84 mW
25.82 mW, Avg: 34.27 mW
26.67 mW, Avg: 33.83 mW
26.96 mW, Avg: 33.45 mW
26.99 mW, Avg: 33.11 mW
27.0 mW, Avg: 32.80 mW
26.99 mW, Avg: 32.52 mW
27.01 mW, Avg: 32.27 mW
28.76 mW, Avg: 32.12 mW
27.48 mW, Avg: 31.93 mW
^C30.57 mW, Avg: 31.87 mW
Traceback (most recent call last):
  File "/home/weiss/repos/ppk2-api-python/examples/example_measure_mw.py", line 107, in <module>
    main()
    ~~~~^^
  File "/home/weiss/repos/ppk2-api-python/examples/example_measure_mw.py", line 102, in main
    input("Press Enter to exit...\n")
    ~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^
KeyboardInterrupt

(.venv) weiss@lobaro-laptop-kw:~/repos/ppk2-api-python$ python examples/example_measure_mw.py
Press Enter to exit...
PPK2 devices found: [('/dev/ttyACM0', 'D06D19AF')]
[('/dev/ttyACM0', 'D06D19AF')]
Connecting to /dev/ttyACM0
Initialized Power Profiler
131.61 mW, Avg: 131.61 mW
27.03 mW, Avg: 79.32 mW
26.74 mW, Avg: 61.79 mW
26.67 mW, Avg: 53.01 mW
26.45 mW, Avg: 47.70 mW
26.33 mW, Avg: 44.14 mW
26.21 mW, Avg: 41.58 mW
26.11 mW, Avg: 39.64 mW
26.07 mW, Avg: 38.14 mW
26.05 mW, Avg: 36.93 mW
26.0 mW, Avg: 35.93 mW
25.95 mW, Avg: 35.10 mW
25.9 mW, Avg: 34.39 mW
25.84 mW, Avg: 33.78 mW
26.46 mW, Avg: 33.29 mW
26.74 mW, Avg: 32.88 mW
26.8 mW, Avg: 32.53 mW
27.01 mW, Avg: 32.22 mW
26.99 mW, Avg: 31.95 mW
27.01 mW, Avg: 31.70 mW
27.43 mW, Avg: 31.50 mW
27.94 mW, Avg: 31.33 mW
29.77 mW, Avg: 31.27 mW

28.88 mW, Avg: 31.17 mW

[MrKevinWeiss]

Suggested change

	from src.ppk2_api.ppk2_api import PPK2_API
	from ppk2_api.ppk2_api import PPK2_API

[MrKevinWeiss]

Works with python3.10 (which is the oldest still supported) and I am a big fan of the type hints.

[MrKevinWeiss]

If you add the small change and squash then I would be happy to merge.

[MrKevinWeiss]

Hmmm testing on a firmware updated ppk I get the first few readings as 0...

Details

$ python examples/example_measure_mw.py
Press Enter to exit...
PPK2 devices found: [('/dev/ttyACM0', 'D06D19AF')]
[('/dev/ttyACM0', 'D06D19AF')]
Connecting to /dev/ttyACM0
Initialized Power Profiler
-0.0 mW, Avg: 0.00 mW
-0.0 mW, Avg: 0.00 mW
-0.0 mW, Avg: 0.00 mW
-0.0 mW, Avg: 0.00 mW
-0.0 mW, Avg: 0.00 mW
-0.0 mW, Avg: 0.00 mW
-0.0 mW, Avg: 0.00 mW
-0.0 mW, Avg: 0.00 mW
-0.0 mW, Avg: 0.00 mW
-0.0 mW, Avg: 0.00 mW
-0.0 mW, Avg: 0.00 mW
25.57 mW, Avg: 2.13 mW
26.42 mW, Avg: 4.00 mW
26.38 mW, Avg: 5.60 mW
26.33 mW, Avg: 6.98 mW
26.35 mW, Avg: 8.19 mW
26.33 mW, Avg: 9.26 mW
26.31 mW, Avg: 10.21 mW
26.42 mW, Avg: 11.06 mW
27.45 mW, Avg: 11.88 mW
27.43 mW, Avg: 12.62 mW
27.43 mW, Avg: 13.29 mW
27.43 mW, Avg: 13.91 mW
27.42 mW, Avg: 14.47 mW
27.43 mW, Avg: 14.99 mW
27.4 mW, Avg: 15.47 mW
29.27 mW, Avg: 15.98 mW
31.07 mW, Avg: 16.52 mW
31.01 mW, Avg: 17.02 mW
30.99 mW, Avg: 17.48 mW
30.97 mW, Avg: 17.92 mW
30.96 mW, Avg: 18.32 mW
30.93 mW, Avg: 18.71 mW
30.95 mW, Avg: 19.07 mW
32.2 mW, Avg: 19.44 mW
32.28 mW, Avg: 19.80 mW
32.28 mW, Avg: 20.14 mW
32.26 mW, Avg: 20.45 mW
32.22 mW, Avg: 20.76 mW
32.25 mW, Avg: 21.04 mW
32.24 mW, Avg: 21.32 mW
30.86 mW, Avg: 21.54 mW
28.22 mW, Avg: 21.70 mW
28.21 mW, Avg: 21.85 mW
28.22 mW, Avg: 21.99 mW
28.22 mW, Avg: 22.12 mW
28.22 mW, Avg: 22.25 mW
28.21 mW, Avg: 22.38 mW
28.19 mW, Avg: 22.50 mW
25.5 mW, Avg: 22.56 mW

24.68 mW, Avg: 22.60 mW
(.venv) weiss@lobaro-laptop-kw:~/repos/ppk2-api-python$ python examples/example_measure_mw.py
Press Enter to exit...
PPK2 devices found: [('/dev/ttyACM0', 'D06D19AF')]
[('/dev/ttyACM0', 'D06D19AF')]
Connecting to /dev/ttyACM0
Initialized Power Profiler
-0.0 mW, Avg: 0.00 mW
-0.0 mW, Avg: 0.00 mW
-0.0 mW, Avg: 0.00 mW
-0.0 mW, Avg: 0.00 mW
-0.0 mW, Avg: 0.00 mW
-0.0 mW, Avg: 0.00 mW
-0.0 mW, Avg: 0.00 mW
-0.0 mW, Avg: 0.00 mW
-0.0 mW, Avg: 0.00 mW
-0.0 mW, Avg: 0.00 mW
-0.0 mW, Avg: 0.00 mW
25.2 mW, Avg: 2.10 mW
26.08 mW, Avg: 3.94 mW
26.05 mW, Avg: 5.52 mW
26.03 mW, Avg: 6.89 mW
26.03 mW, Avg: 8.09 mW
26.04 mW, Avg: 9.14 mW
26.03 mW, Avg: 10.08 mW
26.07 mW, Avg: 10.92 mW
27.22 mW, Avg: 11.74 mW
27.19 mW, Avg: 12.47 mW
27.2 mW, Avg: 13.14 mW
27.2 mW, Avg: 13.75 mW
27.19 mW, Avg: 14.31 mW
27.17 mW, Avg: 14.83 mW
27.19 mW, Avg: 15.30 mW
28.98 mW, Avg: 15.81 mW
30.83 mW, Avg: 16.35 mW
30.77 mW, Avg: 16.84 mW
30.74 mW, Avg: 17.31 mW
30.72 mW, Avg: 17.74 mW
30.69 mW, Avg: 18.14 mW
30.7 mW, Avg: 18.52 mW
30.66 mW, Avg: 18.88 mW
31.91 mW, Avg: 19.25 mW
32.03 mW, Avg: 19.61 mW
32.03 mW, Avg: 19.94 mW
32.01 mW, Avg: 20.26 mW
31.97 mW, Avg: 20.56 mW
32.0 mW, Avg: 20.85 mW
31.99 mW, Avg: 21.12 mW
30.57 mW, Avg: 21.34 mW
28.0 mW, Avg: 21.50 mW
27.95 mW, Avg: 21.65 mW
^CTraceback (most recent call last):
  File "/home/weiss/repos/ppk2-api-python/examples/example_measure_mw.py", line 107, in <module>
    main()
  File "/home/weiss/repos/ppk2-api-python/examples/example_measure_mw.py", line 102, in main
    input("Press Enter to exit...\n")
KeyboardInterrupt

(.venv) weiss@lobaro-laptop-kw:~/repos/ppk2-api-python$ python examples/example_measure_mw.py
Press Enter to exit...
PPK2 devices found: [('/dev/ttyACM0', 'D06D19AF')]
[('/dev/ttyACM0', 'D06D19AF')]
Connecting to /dev/ttyACM0
Initialized Power Profiler
-0.0 mW, Avg: 0.00 mW
-0.0 mW, Avg: 0.00 mW
-0.0 mW, Avg: 0.00 mW
-0.0 mW, Avg: 0.00 mW
-0.0 mW, Avg: 0.00 mW
-0.0 mW, Avg: 0.00 mW
-0.0 mW, Avg: 0.00 mW
-0.0 mW, Avg: 0.00 mW
-0.0 mW, Avg: 0.00 mW
-0.0 mW, Avg: 0.00 mW
-0.0 mW, Avg: 0.00 mW
25.59 mW, Avg: 2.13 mW
26.1 mW, Avg: 3.98 mW
26.1 mW, Avg: 5.56 mW
26.06 mW, Avg: 6.92 mW
26.04 mW, Avg: 8.12 mW
26.02 mW, Avg: 9.17 mW
25.98 mW, Avg: 10.10 mW
26.11 mW, Avg: 10.95 mW
27.19 mW, Avg: 11.76 mW
27.23 mW, Avg: 12.50 mW
27.19 mW, Avg: 13.16 mW
27.19 mW, Avg: 13.77 mW
27.19 mW, Avg: 14.33 mW
27.22 mW, Avg: 14.85 mW
27.22 mW, Avg: 15.32 mW
29.09 mW, Avg: 15.83 mW
30.82 mW, Avg: 16.37 mW
30.74 mW, Avg: 16.86 mW
30.76 mW, Avg: 17.33 mW
30.77 mW, Avg: 17.76 mW
30.74 mW, Avg: 18.17 mW

30.71 mW, Avg: 18.55 mW