Texas Instruments BQ28Z610-R2 Technical Reference Manual Download

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12.1 Standard Data Commands

To enable the system to read and write battery information, the BQ28Z610-R2 uses a series of 2-byte standard
I

C commands with a 7-bit device address of 0x55 (8 bits = 0xAA to write and 0xAB to read). Each standard

command has an associated command code pair, as indicated in

Table 12-1

Standard Commands

. Each

protocol has specific means to access the data at each command code. Data RAM is updated and read by the
gauge once per second.

Table 12-1. Standard Commands

Name

Register Code

(LSB/MSB)

Description

ManufacturerAccess/ControlStatus()

CNTL

0x00/0x01

Control Register (see below)

AtRate()

0x02/0x03

Read/Write. The value is a signed integer with the negative value indicating a discharge current value. The
default value is 0 and forces

AtRateTimeToEmpty()

to return 65,535.

AtRateTimeToEmpty()

ARTTE

0x04/0x05

This read-only function returns an unsigned integer value to predict remaining operating time based on battery
discharge at the

AtRate()

value in minutes with a range of 0 to 65,534. A value of 65,535 indicates

AtRate()

= 0.

The gas gauge updates the

AtRateTimeToEmpty()

within 1 s after the system sets the

AtRate()

value. The gas

gauge updates these parameters every 1 s. The commands are used in NORMAL mode.

Temperature()

TEMP

0x06/0x07

This read-only function returns an unsigned integer value of temperature in units ( 0.1 k) measured by the
gas gauge, and is used for the gauging algorithm. It reports either

InternalTemperature()

or external thermistor

temperature, depending on the setting of the

[TEMPS]

bit in Pack configuration.

Voltage()

VOLT

0x08/0x09

This read-only function returns an unsigned integer value of the measured cell pack in mV with a range of 0
12000 mV.

BatteryStatus()

FLAGS

0x0A/0x0B

See the Flags register.

Current()

INSTCURR

0x0C/0x0D

This read-only function returns a signed integer value that is the instantaneous current flow through the sense
resistor. The value is updated every 1 s. Units are mA.

RemainingCapacity()

0x10/0x11

This read-only command returns the predicted remaining capacity, based on rate (per configured Load Select),
temperature, present depth-of-discharge, and stored impedance. Values are reported in mAh.

FullChargeCapacity()

FCC

0x12/0x13

This read-only command returns the predicted capacity of the battery at full charge, based on rate (per
configured Load Select), temperature, present depth-of-discharge, and stored impedance. Values are reported in
mAh.

AverageCurrent

0x14/0x15

This read-only function returns a signed integer value that is the average current flow through the sense resistor.
The value is updated every 1 s. Units are mA.

AverageTimeToEmpty

TTE

0x16/0x17

Uses average current value with a time constant of 15 s for this method. A value of 65535 means the battery is
not being discharged.

AverageTimeToFull

TTF

0x18/0x19

This read-only function returns a unsigned integer value, predicting time to reach full charge for the battery in
units of minutes based on

AverageCurrent()

. The computation accounts for the taper current time extension

from linear TTF computation based on a fixed

AverageCurrent()

rate of charge accumulation. A value of 65,535

indicates the battery is not being charged.

StandbyCurrent

0x1A/0x1B

This read-only function returns a signed integer value of measured standby current through the sense resistor.
The

StandbyCurrent()

is an adaptive measurement. Initially it will report the standby current programmed in

initial standby, and after several seconds in standby mode will report the measured standby. The register value is
updated every 1 s when measured current is above the deadband and is less than or equal to 2 × initial standby.
The first and last values that meet these criteria are not averaged in, since they may not be stable values. To
approximate to a 1-min time constant, each new value of

StandbyCurrent()

is computed by taking approximate

93% weight of the last standby current and approximate 7% of the current measured average current.

StandbyTimeToEmpty

STTE

0x1C/0x1D

This read-only function returns a unsigned integer value, predicting remaining battery life at standby rate of
discharge in units of minutes. The computation uses Nominal Available Capacity (NAC) for the calculation. A
value of 65,535 indicates the battery is not being discharged.

MaxLoadCurrent

MLI

0x1E/0x1F

This read-only function returns a signed integer value in units of mA, of maximum load conditions. The

MaxLoadCurrent()

is an adaptive measurement which is initially reported as the maximum load current

programmed in initial Max Load Current register. If the measured current is ever greater than the initial Max Load
Current then the

MaxLoadCurrent()

updates to the new current.

MaxLoadCurrent()

is reduced to the average

of the previous value and initial Max Load Current whenever the battery is charged to full after a previous
discharge to an SOC of less than 50%. This will prevent the reported value from maintaining an unusually high
value.

MaxLoadTimeToEmpty

MLTTE

0x20/0x21

This read-only function returns a unsigned integer value, predicting remaining battery life at the maximum
discharge load current rate in units of minutes. A value of 65,535 indicates that the battery is not being
discharged.

Chapter 12

I2C Commands

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I2C Commands

SLUUCO0 – APRIL 2022

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