A Python library for talking to the AXP209 power management unit

AXP209 is a pmu that is used on quite few Allwinner embeded boards, like C.H.I.P and Cubietruck.

Because currently the sysfs api for AXP209 is in flux I wrote this library that bypasses the kernel and directly talks to the AXP209 over I2C bus using smbus2 library.

This library runs on both Python 2.7 and Python 3

Installation

pip install axp209

SMBus bus number/object

The default SMBus object set in this library is an integer 0. You might need to change to another integer[like 1] depending on your system, or pass an object. e.g. axp = AXP209(1) for the Olimex A20-SOM204.

Examples

>>> from axp209 import AXP209
>>> axp = AXP209()
>>> axp.battery_voltage
4144.8
>>> axp.battery_discharge_current
269.0
>>>

Read and print out all the battery status values

from axp209 import AXP209

axp = AXP209()
print("internal_temperature: %.2fC" % axp.internal_temperature)
print("battery_exists: %s" % axp.battery_exists)
print("battery_charging: %s" % ("charging" if axp.battery_charging else "done"))
print("battery_current_direction: %s" % ("charging" if axp.battery_current_direction else "discharging"))
print("battery_voltage: %.1fmV" % axp.battery_voltage)
print("battery_discharge_current: %.1fmA" % axp.battery_discharge_current)
print("battery_charge_current: %.1fmA" % axp.battery_charge_current)
print("battery_gauge: %d%%" % axp.battery_gauge)
axp.close()

Blink CHIP status led

from time import sleep
from axp209 import AXP209

with AXP209() as axp:
    while True:
        axp.gpio2_output = False
        sleep(1)
        axp.gpio2_output = True
        sleep(1)

There is also a commandline utility than you can use after installing it

root@sumochip1:~# axp209
internal_temperature: 67.00C
battery_exists: True
battery_charging: charging
battery_current_direction: discharging
battery_voltage: 3974.3mV
battery_discharge_current: 0.0mA
battery_charge_current: 0.0mA
battery_gauge: 76%
root@sumochip1:~#