bq27441: add driver for the LiPo Fuel Gauge

Author: nedseb

lib/bq27441/README.md

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+# MicroPython BQ27441 Library
+
+This library is a port of the [SparkFun BQ27441-G1A LiPo Fuel Gauge Arduino Libraryry](https://github.com/sparkfun/SparkFun_BQ27441_Arduino_Library).
+
+The examples could be easily tested with [mpremote](https://docs.micropython.org/en/latest/reference/mpremote.html) with the following command :
+
+```sh
+mpremote mount . run examples/fuel_gauge.py
+```

lib/bq27441/bq27441/__init__.py

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+from bq27441.device import BQ27441
+
+__all__ = [ 'BQ27441', ]

lib/bq27441/bq27441/const.py

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+##### Lipo Battery Capacity
+LIPO_BATTERY_CAPACITY = 650 # 850 mAh
+#####
+
+BQ27441_I2C_ADDRESS = 0x55  # Default I2C address of the BQ27441-G1A
+
+###########/
+# General Constants #
+###########/
+BQ27441_UNSEAL_KEY	= 0x8000 # Secret code to unseal the BQ27441-G1A
+BQ27441_DEVICE_ID	= 0x0421 # Default device ID
+
+###########/
+# Standard Commands #
+###########/
+# The fuel gauge uses a series of 2-byte standard commands to enable system
+# reading and writing of battery information. Each command has an associated
+# sequential command-code pair.
+BQ27441_COMMAND_CONTROL			= 0x00 # Control()
+BQ27441_COMMAND_TEMP			= 0x02 # Temperature()
+BQ27441_COMMAND_VOLTAGE			= 0x04 # Voltage()
+BQ27441_COMMAND_FLAGS			= 0x06 # Flags()
+BQ27441_COMMAND_NOM_CAPACITY	= 0x08 # NominalAvailableCapacity()
+BQ27441_COMMAND_AVAIL_CAPACITY	= 0x0A # FullAvailableCapacity()
+BQ27441_COMMAND_REM_CAPACITY	= 0x0C # RemainingCapacity()
+BQ27441_COMMAND_FULL_CAPACITY	= 0x0E # FullChargeCapacity()
+BQ27441_COMMAND_AVG_CURRENT		= 0x10 # AverageCurrent()
+BQ27441_COMMAND_STDBY_CURRENT	= 0x12 # StandbyCurrent()
+BQ27441_COMMAND_MAX_CURRENT		= 0x14 # MaxLoadCurrent()
+BQ27441_COMMAND_AVG_POWER		= 0x18 # AveragePower()
+BQ27441_COMMAND_SOC				= 0x1C # StateOfCharge()
+BQ27441_COMMAND_INT_TEMP		= 0x1E # InternalTemperature()
+BQ27441_COMMAND_SOH				= 0x20 # StateOfHealth()
+BQ27441_COMMAND_REM_CAP_UNFL	= 0x28 # RemainingCapacityUnfiltered()
+BQ27441_COMMAND_REM_CAP_FIL		= 0x2A # RemainingCapacityFiltered()
+BQ27441_COMMAND_FULL_CAP_UNFL	= 0x2C # FullChargeCapacityUnfiltered()
+BQ27441_COMMAND_FULL_CAP_FIL	= 0x2E # FullChargeCapacityFiltered()
+BQ27441_COMMAND_SOC_UNFL		= 0x30 # StateOfChargeUnfiltered()
+
+#############
+# Control Sub-commands #
+#############
+# Issuing a Control() command requires a subsequent 2-byte subcommand. These
+# additional bytes specify the particular control function desired. The
+# Control() command allows the system to control specific features of the fuel
+# gauge during normal operation and additional features when the device is in
+# different access modes.
+BQ27441_CONTROL_STATUS			= 0x00
+BQ27441_CONTROL_DEVICE_TYPE		= 0x01
+BQ27441_CONTROL_FW_VERSION		= 0x02
+BQ27441_CONTROL_DM_CODE			= 0x04
+BQ27441_CONTROL_PREV_MACWRITE	= 0x07
+BQ27441_CONTROL_CHEM_ID			= 0x08
+BQ27441_CONTROL_BAT_INSERT		= 0x0C
+BQ27441_CONTROL_BAT_REMOVE		= 0x0D
+BQ27441_CONTROL_SET_HIBERNATE	= 0x11
+BQ27441_CONTROL_CLEAR_HIBERNATE	= 0x12
+BQ27441_CONTROL_SET_CFGUPDATE	= 0x13
+BQ27441_CONTROL_SHUTDOWN_ENABLE	= 0x1B
+BQ27441_CONTROL_SHUTDOWN		= 0x1C
+BQ27441_CONTROL_SEALED			= 0x20
+BQ27441_CONTROL_PULSE_SOC_INT	= 0x23
+BQ27441_CONTROL_RESET			= 0x41
+BQ27441_CONTROL_SOFT_RESET		= 0x42
+BQ27441_CONTROL_EXIT_CFGUPDATE	= 0x43
+BQ27441_CONTROL_EXIT_RESIM		= 0x44
+
+#####################/
+# Control Status Word - Bit Definitions #
+#####################/
+# Bit positions for the 16-bit data of CONTROL_STATUS.
+# CONTROL_STATUS instructs the fuel gauge to return status information to
+# Control() addresses 0x00 and 0x01. The read-only status word contains status
+# bits that are set or cleared either automatically as conditions warrant or
+# through using specified subcommands.
+BQ27441_STATUS_SHUTDOWNEN	= (1<<15)
+BQ27441_STATUS_WDRESET		= (1<<14)
+BQ27441_STATUS_SS			= (1<<13)
+BQ27441_STATUS_CALMODE		= (1<<12)
+BQ27441_STATUS_CCA			= (1<<11)
+BQ27441_STATUS_BCA			= (1<<10)
+BQ27441_STATUS_QMAX_UP		= (1<<9)
+BQ27441_STATUS_RES_UP		= (1<<8)
+BQ27441_STATUS_INITCOMP		= (1<<7)
+BQ27441_STATUS_HIBERNATE	= (1<<6)
+BQ27441_STATUS_SLEEP		= (1<<4)
+BQ27441_STATUS_LDMD			= (1<<3)
+BQ27441_STATUS_RUP_DIS		= (1<<2)
+BQ27441_STATUS_VOK			= (1<<1)
+
+##################
+# Flag Command - Bit Definitions #
+##################
+# Bit positions for the 16-bit data of Flags()
+# This read-word function returns the contents of the fuel gauging status
+# register, depicting the current operating status.
+BQ27441_FLAG_OT			= (1<<15)
+BQ27441_FLAG_UT			= (1<<14)
+BQ27441_FLAG_FC			= (1<<9)
+BQ27441_FLAG_CHG		= (1<<8)
+BQ27441_FLAG_OCVTAKEN	= (1<<7)
+BQ27441_FLAG_ITPOR		= (1<<5)
+BQ27441_FLAG_CFGUPMODE	= (1<<4)
+BQ27441_FLAG_BAT_DET	= (1<<3)
+BQ27441_FLAG_SOC1		= (1<<2)
+BQ27441_FLAG_SOCF		= (1<<1)
+BQ27441_FLAG_DSG		= (1<<0)
+
+##############
+# Extended Data Commands #
+##############
+# Extended data commands offer additional functionality beyond the standard
+# set of commands. They are used in the same manner; however, unlike standard
+# commands, extended commands are not limited to 2-byte words.
+BQ27441_EXTENDED_OPCONFIG	= 0x3A # OpConfig()
+BQ27441_EXTENDED_CAPACITY	= 0x3C # DesignCapacity()
+BQ27441_EXTENDED_DATACLASS	= 0x3E # DataClass()
+BQ27441_EXTENDED_DATABLOCK	= 0x3F # DataBlock()
+BQ27441_EXTENDED_BLOCKDATA	= 0x40 # BlockData()
+BQ27441_EXTENDED_CHECKSUM	= 0x60 # BlockDataCheckSum()
+BQ27441_EXTENDED_CONTROL	= 0x61 # BlockDataControl()
+
+####################
+# Configuration Class, Subclass ID's #
+####################
+# To access a subclass of the extended data, set the DataClass() function
+# with one of these values.
+# Configuration Classes
+BQ27441_ID_SAFETY			= 2   # Safety
+BQ27441_ID_CHG_TERMINATION	= 36  # Charge Termination
+BQ27441_ID_CONFIG_DATA		= 48  # Data
+BQ27441_ID_DISCHARGE		= 49  # Discharge
+BQ27441_ID_REGISTERS		= 64  # Registers
+BQ27441_ID_POWER		    = 68  # Power
+# Gas Gauging Classes
+BQ27441_ID_IT_CFG			= 80  # IT Cfg
+BQ27441_ID_CURRENT_THRESH	= 81  # Current Thresholds
+BQ27441_ID_STATE			= 82  # State
+# Ra Tables Classes
+BQ27441_ID_R_A_RAM			= 89  # R_a RAM
+# Calibration Classes
+BQ27441_ID_CALIB_DATA		= 104 # Data
+BQ27441_ID_CC_CAL			= 105 # CC Cal
+BQ27441_ID_CURRENT			= 107 # Current
+# Security Classes
+BQ27441_ID_CODES			= 112 # Codes
+
+####################/
+# OpConfig Register - Bit Definitions #
+####################/
+# Bit positions of the OpConfig Register
+BQ27441_OPCONFIG_BIE      = (1<<13)
+BQ27441_OPCONFIG_BI_PU_EN = (1<<12)
+BQ27441_OPCONFIG_GPIOPOL  = (1<<11)
+BQ27441_OPCONFIG_SLEEP    = (1<<5)
+BQ27441_OPCONFIG_RMFCC    = (1<<4)
+BQ27441_OPCONFIG_BATLOWEN = (1<<2)
+BQ27441_OPCONFIG_TEMPS    = (1<<0)
+
+BQ27441_I2C_TIMEOUT      = 2000 # ms