Intermittent Error 5 Input / Output Error

[Mikefly123]

Doing some testing with the basic PyCubed functionality and hit an odd occurrence of Error 5.

Interestingly the power monitor is only erroring when we try to call the current_draw. All the other functions are okay. In the past when we get Error 5, usually the entire power monitor is out of action. A hard reset of the entire system does not clear this error.

[maholli]

Hi @Mikefly123 sorry for missing this - I hadn't changed my github email over after graduating 😄

I believe this is a fleeting bug arising from abnormal I2C initialization behavior of the ADM1176 power monitor chip. For example, if you were to keep deleting the cubesat.pwr object and trying again (without resetting or power cycling), it would eventually work. I've never been able to consistently reproduce this error with any of my boards, so I've never really dug deep.

Once thing to try is to change your pycubed.py line that creates the i2c object (line 91 on the latest in the repo) to say:
... = busio.I2C(board.SCL,board.SDA, frequency=400000)
In other words, change the i2c1 bus frequency to 400khz instead of the default 100khz.

Report back and let me know how that goes.

[Mikefly123]

Hi @maholli, congratulations on become Dr. Holliday!

Changing the speed of the i2c bus unfortunately doesn't seem to bring the power monitor back to life, but I do recognize Error 5 from when we tried to implement a BNO080 on BroncoSat-1. In that case we were able to occasionally get the BNO080 to make it through init by creating and deleting the object until it worked. We think that in that case there was an issue with i2c clock stretching not being implemented in CircuitPython.

I will report back if we figure anything out during continued testing!

[maholli]

Thanks! And you make an excellent point! I hadn't considered an odd-ball clock stretching case... If that's what's happening here, there are always options :)

1. I know CP implemented adjustable I2C bus speeds in the native busio - I'm just not sure if it's fixed to 100kHz & 400kHz, or if it can go lower. Try changing the speed of the bus again but make it 10kHz and see if that helps. Make sure to power cycle the board to force the peripheral (whether it be an BNO080 or ADM1176) to cold-init again.
2. If the above doesn't work - try initializing that i2c bus using bitbangio rather than busio. With bitbangio you'll certainly be able to set the clock speed 10kHz and see if that fixes the problem at hand.

Let me know how it goes!