FrequencyIO on CircuitPython 7.0.0 only returns 0. Same setup works with 6.3.0.

[FevenKitsune]

CircuitPython version

Adafruit CircuitPython 7.0.0 on 2021-09-20; Adafruit Feather M4 Express with samd51j19

Code/REPL

# CircuitPython 7.0
import frequencyio
import board
import time

frequency = frequencyio.FrequencyIn(board.D11)

# Loop while printing the detected frequency
while True:
    print(frequency.value)

    # Optional clear() will reset the value
    # to zero. Without this, if the incoming
    # signal stops, the last reading will remain
    # as the value.
    frequency.clear()
    time.sleep(0.1)

Behavior

Signal is generated with an external signal generator (-40.0mV-3.26v Pk-Pk, 1kHz Square Wave).

Serial output with CircuitPython 7.0.0:

0
0
0
0
0
...

Serial output with CircuitPython 6.3.0:

1000
1164
1000
1000
1058
...

Behavior is observed at higher frequencies as well.

Description

No response

Additional information

Did some debugging with @dhalbert on the Adafruit Discord server.

• Swapped coax cable.
• Validated normal GPIO operation with pin.
  

[dhalbert]

This appears to be some kind of initialization problem. It works the first time:

[power-cycle]
Adafruit CircuitPython 7.0.0 on 2021-09-20; Adafruit Feather M4 Express with samd51j19
>>> 
>>> import board,frequencyio
>>> frequency = frequencyio.FrequencyIn(board.D11)
>>> frequency.value
529
>>> [ctrl-D]
soft reboot

Auto-reload is on. Simply save files over USB to run them or enter REPL to disable.
code.py output:
Hello World!

Code done running.

Press any key to enter the REPL. Use CTRL-D to reload.

Adafruit CircuitPython 7.0.0 on 2021-09-20; Adafruit Feather M4 Express with samd51j19
>>> import board,frequencyio
>>> frequency = frequencyio.FrequencyIn(board.D11)
>>> frequency.value
0
>>> 

[dhalbert]

Fixed by #5665.