I2C error after soft reboot

[BrianPugh]

I am having a very similar issue outlined in this issue:
adafruit/circuitpython#2060

Essentially, I am able to communicate with the VEML7700 on first boot from my nRF52840, but subsequent soft reboots (such as during code reloads) cause the traceback as follows:

>>> veml7700 = adafruit_veml7700.VEML7700(i2c)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/lib/adafruit_veml7700.py", line 207, in __init__
  File "adafruit_register/i2c_bit.py", line 70, in __set__
  File "adafruit_register/i2c_bit.py", line 65, in __set__
  File "adafruit_bus_device/i2c_device.py", line 143, in write_then_readinto
OSError: [Errno 19] Unsupported operation

Through experimentation, I have found that this can be mitigated by replacing this line:

Adafruit_CircuitPython_VEML7700/adafruit_veml7700.py

Line 206 in f57ccd9

self.light_shutdown = False # Enable the ambient light sensor

with:

try:
    self.light_shutdown = False
except OSError:
    self.light_shutdown = False

On a cold boot, the first self.light_shutdown = False works successfully. On subsequent soft reboots, it will fail with the traceback previously mentioned; however, running the command again always works. I guess maybe the first attempt flushs some buffer or fixes some invalid state?

I can make a PR if convenient, but just checking if this maybe is just a symptom of an upstream bug that should be fixed instead.

[ladyada]

hi idea is good! for implementation i think better to perhaps have a loop where it tries 3 times to enable, and if it does not enable (else: at the end of the for loop) it throws a runtime error

[BrianPugh]

cool! I'll make a PR soon with this change

[BrianPugh]

closing since PR15 has been merged

[jposada202020]

@BrianPugh Thanks :)