INA228 micropython driver

Copy of https://github.com/megalloid/INA228 modded for micropython for the PICO

Bug(?) fix 11/18 - get routines were printing values but returning 'None'

Note - (*DON'T TRUST ME ON THIS - CHECK DOCS!!) Seems like V- needs to be connected GND, otherwise VBUS measurement floats ~ 2.5V high. At least for my use case measuring current on low side. Beware if you do this, make sure your power to chip is isolated from circut under test or has appropriate ground reference. Wish I knew what I was talking about, sigh...

I don't claim to understand git well, so if this not being a formal fork offends anyone, my apologies.

My sincerest thanks to Megalloid - the 228 is the chip I've been waiting for to use in my homebrew off-grid 48V PV system

Also thanks to Adafruit for making a breakout board!

Simple example:

from machine import I2C, Pin
import ina228
# address and shunt_ohms shown are default for Adafruit breakout
sensor = ina228.INA228(I2C(0, sda=Pin(4), scl=Pin(5)), address=64,shunt_ohms=0.015) 
sensor.reset_all()
print(sensor.get_current())
print(sensor.get_manufacturer_id())

Note there are many other methods, getting voltage and power, setting calibration and offsets, testing for alerts, etc.