OSError: [Errno 19] ENODEV on WeMos D1 Mini

[mcauser]

Thanks for the library! I'm going to use to to upgrade an old RC car with an ESP8266 and use this as the controller.

I am getting consistent OSError: [Errno 19] ENODEV errors when I use your library with MicroPython v1.8.6-172 on a WeMos D1 Mini v2.1.0

>>> from machine import Pin, I2C
>>> import time
>>> import nunchuck
>>> i2c = I2C(scl=Pin(5),sda=Pin(4),freq=100000)
>>> i2c.scan()
[82]
>>> nun = nunchuck.Nunchuck(i2c)
>>> print(nun.joystick_x(), nun.joystick_y())
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "nunchuck.py", line 103, in joystick_y
  File "nunchuck.py", line 47, in __poll
  File "nunchuck.py", line 42, in update
OSError: [Errno 19] ENODEV

In def update(self):, I added a small delay, and now it's working reliably for me now.

def update(self):
    self.i2c.writeto(self.address, b'\x00')
    time.sleep_us(10)
    self.i2c.readfrom_into(self.address, self.buffer)

• time.sleep_us(3) OSError 19s after 2-10 calls.
• time.sleep_us(5) OSError 19s after 10-50 calls.
• time.sleep_us(10) works consistently.

I am using one of these little Wiichuck adapters:

https://littlebirdelectronics.com.au/products/wiichuck-adapter

[kfricke]

TBH i have not yet had time to test this on my ESPs.

Thanks for this report and possible solution. 10 µs should not really harm in any way with I2C communication. i will try to dig for the dependency for your delay in the datasheet of the Nunchuck chip.

We hopefully will find a report including photos of your project on the µPy forum!?

[mcauser]

Tested on two of my WeMos D1 Minis, V2 and V2.1.0 boards, also upgraded to MicroPython v1.8.6-183-ge8f2db7
I forgot the Nunchuk had an accelerometer. Win!

I'll be sure to document the build on the forum and share the code on my GitHub.

[jmeri]

Tested this code on an ESP-12E, and found out it was working only intermittently. Sometimes I could get readings, sometimes couldn't, and nunchuck_test was totally unusable. Then, I switched the I2C-bus to other pins than 4 and 5, and it worked like a charm! Pins 4 & 5 seem to be ok otherwise, haven't shown them to my scope yet...
Anyway, thank you fo the code!

[JonPenner]

ESP-01 running MicroPython v1.9.4, also had the 'OSError: [Errno 19] ENODEV' bug. I tried sleep_us values of 10 and 20 with no success. 50 makes it work, but I'm sure I can find a smaller number.