Marine Instruments User Manual

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bq27500
bq27501
System-Side Impedance Track™ Fuel Gauge
SLUS785 – SEPTEMBER 2007
4.1.1.1.15 CAL MODE: 0x0040
This command instructs the fuel gauge to enter calibration mode. This command is only available when
the fuel gauge is UNSEALED.
4.1.1.1.16 RESET: 0x0041
This command instructs the fuel gauge to perform a full reset. This command is only available when the
fuel gauge is UNSEALED.
4.1.1.2 AtRate( ): 0x02/0x03
The AtRate( ) read-/write-word function is the first half of a two-function command-set used to set the
AtRate value used in calculations made by the AtRateTimeToEmpty( ) function. The AtRate( ) units are in
mA.
The AtRate( ) value is a signed integer, and both positive and negative values will be interpreted as a
discharge current value. The AtRateTimeToEmpty( ) function returns the predicted operating time at the
AtRate value of discharge. The default value for AtRate( ) is zero and will force AtRate( ) to return 65535.
Both the AtRate( ) and AtRateTimeToEmpty( ) commands should only be used in NORMAL mode.
4.1.1.3 AtRateTimeToEmpty( ): 0x04/0x05
This read-word function returns an unsigned integer value of the predicted remaining operating time if the
battery is discharged at the AtRate( ) value in minutes with a range of 0 to 65534. A value of 65535
indicates AtRate( ) = 0. The gas gauge updates AtRateTimeToEmpty( ) within 1s after the system sets the
AtRate( ) value. The fuel gauge automatically updates AtRateTimeToEmpty( ) based on the AtRate( )
value every 1s. Both the AtRate( ) and AtRateTimeToEmpty( ) commands should only be used in
NORMAL mode.
4.1.1.4 Temperature( ): 0x06/0x07
This read-word function returns an unsigned integer value of the temperature in units of 0.1 ° K measured
by the gas gauge and has a range of 0 to 6553.5 ° K.
4.1.1.5 Voltage( ): 0x08/0x09
This read-word function returns an unsigned integer value of the measured cell-pack voltage in mV with a
range of 0 to 6000 mV.
4.1.1.6 Flags( ): 0x0a/0x0b
This read-word function returns the contents of the gas-gauge status register, depicting the current
operating status.
Table 4-4. Flags Bit Definitions
bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0
High Byte OTC OTD – – CHG_INH XCHG FC CHG
Low Byte CC_OFF – OCV_GD WAIT_ID BAT_DET SOC1 SOCF DSG
OTC = Overtemperature in Charge condition is detected. True when set.
OTD = Overtemperature in Discharge condition is detected. True when set.
CHG_INH = Charge Inhibit: unable to begin charging (temp outside the range [Charge Inhibit Temp Low, Charge Inhibit Temp High]).
True when set.
XCHG = Charge Suspend Alert (temp outside the range [Suspend Temp Low, Suspend Temp High]). True when set.
FC = Fully Charged, set when Charge termination condition is met. True when set.
CHG = (Fast)charging allowed. True when set.
CC_OFF = bq27500/1 performing Coulomb Counter Offset measurement. True when set.
OCV_GD = Good OCV measurement taken. True when set.
WAIT_ID = Waiting to identify inserted battery. True when set.
BAT_DET = Battery detected. True when set.
SOC1 = State-of-Charge-Threshold 1 ( SOC1 Set) reached. True when set.
SOCF = State-of-Charge-Threshold Final ( SOCF Set %) reached. True when set.
DSG = Discharging detected. True when set.
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