Datasheet

bq34z100
SLUSAU1B –MAY 2012–REVISED DECEMBER 2012 www.ti.com
CHG_INH: Charge Inhibit: unable to begin charging [Charge Inhibit Temp Low, Charge Inhibit Temp
High]. True when set.
RSVD: Reserved.
FC: Full-charge is detected. FC is set when charge termination is reached and FC Set% = –1
(see CHARGING AND CHARGE TERMINATION INDICATION for details) or State of Charge
is larger than FC SET% and FC Set% is not –1. True when set.
CHG: (Fast) charging allowed. True when set.
OCVTAKEN: Cleared on entry to relax mode and set to 1 when OCV measurement is performed in relax
mode.
ISD: Internal Short is detected. True when set. TDD = Tab Disconnect is detected. True when set.
SOC1: State-of-Charge Threshold 1 reached. True when set.
SOCF: State-of-Charge Threshold Final reached. True when set.
DSG: Discharging detected. True when set.
DATA FLASH INTERFACE
ACCESSING DATA FLASH
The bq34z100 data flash is a non-volatile memory that contains bq34z100 initialization, default, cell status,
calibration, configuration, and user information. The data flash can be accessed in several different ways,
depending on what mode the bq34z100 is operating in and what data is being accessed.
Commonly accessed data flash memory locations, frequently read by a host, are conveniently accessed through
specific instructions described in DATA COMMANDS. These commands are available when the bq34z100 is
either in UNSEALED or SEALED modes.
Most data flash locations, however, can only accessible in UNSEALED mode by use of the bq34z100 evaluation
software or by data flash block transfers. These locations should be optimized and/or fixed during the
development and manufacture processes. They become part of a Golden Image File and can then be written to
multiple battery packs. Once established, the values generally remain unchanged during end-equipment
operation.
To access data flash locations individually, the block containing the desired data flash location(s) must be
transferred to the command register locations, where they can be read to the host or changed directly. This is
accomplished by sending the set-up command BlockDataControl() (code 0x61) with data 0x00. Up to 32 bytes of
data can be read directly from the BlockData() command locations 0x40…0x5f, externally altered, then re-written
to the BlockData() command space. Alternatively, specific locations can be read, altered, and re-written if their
corresponding offsets are used to index into the BlockData() command space. Finally, the data residing in the
command space is transferred to data flash, once the correct checksum for the whole block is written to
BlockDataChecksum() (command number 0x60).
Occasionally, a data flash CLASS will be larger than the 32-byte block size. In this case, the DataFlashBlock()
command is used to designate which 32-byte block the desired locations reside in. The correct command
address is then given by 0x40 + offset modulo 32. For example, to access Terminate Voltage in the Gas
Gauging class, DataFlashClass() is issued 80 (0x50) to set the class. Because the offset is 48, it must reside in
the second 32-byte block. Hence, DataFlashBlock() is issued 0x01 to set the block offset, and the offset used to
index into the BlockData() memory area is 0x40 + 48 modulo 32 = 0x40 + 16 = 0x40 + 0X10 = 0x50.
Reading and writing subclass data are block operations 32 bytes in length. Data can be written in shorter block
sizes, however. Blocks can be shorter than 32 bytes in length. Writing these blocks back to data flash will not
overwrite data that extend beyond the actual block length.
None of the data written to memory are bounded by the bq34z100—the values are not rejected by the gas
gauge. Writing an incorrect value may result in hardware failure due to firmware program interpretation of the
invalid data. The data written is persistent, so a Power-On Reset does resolve the fault.
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