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drivers: battery: Finalize docstrings

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Daniel Thompson 2020-05-14 21:31:22 +01:00
parent 4af873c9e3
commit 85079c149b
2 changed files with 42 additions and 9 deletions
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docs/wasp.rst
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@ -38,7 +38,6 @@ Device drivers
.. automodule:: drivers.battery
:members:
:undoc-members:
.. automodule:: drivers.cst816s
:members:

50
wasp/drivers/battery.py
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@ -1,35 +1,69 @@
# SPDX-License-Identifier: LGPL-3.0-or-later
# Copyright (C) 2020 Daniel Thompson
# Generic lithium ion battery driver
"""Generic lithium ion battery driver
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
"""
from machine import Pin, ADC
class Battery(object):
"""Generic lithium ion battery driver.
.. automethod:: __init__
"""
def __init__(self, battery, charging, power=None):
"""Specify the pins used to provide battery status.
:param Pin battery: The ADC-capable pin that can be used to measure
battery voltage.
:param Pin charging: A pin (or Signal) that reports the charger status.
:param Pin power: A pin (or Signal) that reports whether the device
has external power, defaults to None (which means
use the charging pin for power reporting too).
"""
self._battery = ADC(battery)
self._charging = charging
self._power = power
def charging(self):
"""Get the charging state of the battery.
:returns: True if the battery is charging, False otherwise.
"""
return self._charging.value()
def power(self):
"""Check whether the device has external power.
:returns: True if the device has an external power source, False
otherwise.
"""
if self._power:
return self._power.value()
return self._charging.value()
def voltage_mv(self):
# Assumes a 50/50 voltage divider and a 3.3v power supply
"""Read the battery voltage.
Assumes a 50/50 voltage divider and a 3.3v power supply
:returns: Battery voltage, in millivolts.
"""
raw = self._battery.read_u16()
return (2 * 3300 * raw) // 65535
def level(self):
# This is a trivial battery level estimation approach. It is assumes
# the discharge from 4v to 3.5v is roughly linear and 4v is 100% and
# that 3.5v is 5%. Below 3.5v the voltage will start to drop pretty
# sharply to we will drop from 5% to 0% pretty fast... but we'll
# live with that for now.
"""Estimate the battery level.
The current the estimation approach is extremely simple. It is assumes
the discharge from 4v to 3.5v is roughly linear and 4v is 100% and
that 3.5v is 5%. Below 3.5v the voltage will start to drop pretty
sharply to we will drop from 5% to 0% pretty fast... but we'll
live with that for now.
:returns: Estimate battery level in percent.
"""
mv = self.voltage_mv()
level = ((19 * mv) // 100) - 660
if level > 100: