BQ27000 Datasheet, PDF (13/29 Pages) Texas Instruments – SINGLE CELL Li-Ion AND Li-Pol BATTERY GAS GAUGE IC FOR PORTABLE APPLICATIONS (bqJUNIOR)

bq27000, bq27200
www.ti.com
SLUS556B – SEPTEMBER 2004 – REVISED NOVEMBER 2004
APPLICATION INFORMATION
Device Control Register (CTRL) — Address 0x00
The device control register is used by the host system to request special operations by the bqJUNIOR. The
highest priority command set in the MODE register is performed when the host writes data 0xA9 or 0x56 as
indicated to the control register. The CTRL register is cleared when the action is complete. Note that writing any
value other than 0xA9 or 0x56 has no effect.
Table 2. Mode Register (MODE) — Address 0x01
COMMAND KEY = 0xA9
COMMAND KEY = 0x56
BIT 7
GPIEN
GPIEN
BIT 6
GPSTAT
GPSTAT
BIT 5
WRTNAC
CEO
BIT 4
DONE
CIO
BIT 3
PRST
N/A
BIT 2
POR
POR
BIT 1
FRST
N/A
BIT 0
SHIP ⁽¹⁾
N/A
(1) bq27200 only
GPIEN
GPIEN sets the state of the GPIO pin. A 1 configures the GPIO pin as input, while a 0 configures
the GPIO pin as an open-drain output. This bit is initialized to the value of bit 7 of the PKCFG
register in the EEPROM. The user should keep this bit set or cleared as desired when other bits in
this register are written.
GPSTAT
WRTNAC
DONE
PRST
GPSTAT sets the state of the open drain output of the GPIO pin (GPIEN = 0). A 1 turns off the
open drain output while a 0 turns the output on. This bit is set to 1 on POR. When the GPIO pin is
an input (GPIEN=1), this bit returns the logic state of the GPIO pin. The user should keep this bit
set or cleared as desired when other bits in this register are written.
WRTNAC is used to transfer data from the AR registers to the NAC and CACD registers. Other
registers are updated as appropriate. This command is useful during the pack manufacture and test
to initialize the gauge to match the estimated battery capacity.
DONE is used to write NAC to LMD. Useful if the host uses a charge termination method that does
not allow the monitor to detect the taper current. The host system could use this command when
the charging is complete to force update of internal registers to a full battery condition.
Partial reset. This command requests a reset of all RAM registers except NAC, LMD, and the CI bit
in FLAGS. This command is intended for manufacturing use.
POR
The POR status bit is set to 1 by the bqJUNIOR following a Power on Reset. This is a flag to the
host that V_CC was less than V_(POR) and caused a reset. The bit is cleared to 0 by the bqJUNIOR
when a full charge condition is reached or it may be cleared by the host. The bit is also cleared to 0
after exiting from EEPROM programming or ship. The host may set this bit, but it has no effect on
the bqJUNIOR operation. The user should keep this bit set or cleared as desired when other bits in
this register are set.
FRST
Full reset. This command bit requests a full reset. A full reset reinitializes all RAM registers,
including the NAC, LMD, and FLAGS registers. This command is intended for manufacturing use.
SHIP
This command bit requests that the device (bq27000 only) should be put in ship mode. See the
Power Mode section for a description of the ship mode. This command is intended for
manufacturing use.
CEO
This command bit requests that the external offset value is measured. Care should be taken to
insure that no charge or discharge current flows during the time this measurement is made. The
external offset value is the total offset of the DSCC plus any external PCB affects. The result can
be read in 0x5f-5e. The result is a signed number with an LSB value of 1.225 µV. The command
takes approximately 5.5 seconds to make the measurement. This command is intended for
manufacturing use.
CIO
This command bit requests that the internal offset value is measured. The internal offset value is
the offset of the DSCC with an internal short applied from SRP to SRN. The result can be read in
0x5f-5e. The result is a signed number with an LSB value of 1.225 µV. The command takes
approximately 5.5 seconds to make the measurement. This command is intended for manufacturing
use.
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