BQ2085 Datasheet, PDF (23/56 Pages) Texas Instruments – SBS-COMPLIANT GAS GAUGE IC FOR USE WITH THE bq29311

bq2085
SLUS541 – OCTOBER 2002
SMBus On and Off State
The bq2085 detects whether the SMBus enters the Off State by monitoring the SMBC and SMBD lines. When
both signals are continually low for at least 2.0 s, the bq2085 detects the Off State. When the SMBC and SMBD
lines go high, the bq2085 detects the On State and can begin communication within 1 ms. One-MΩ pulldown
resistors on SMBC and SMBD are recommended for reliable Off State detection.
Command Codes
The SMBus command codes are in ( ). Temperature( ), Voltage( ), Current( ), and AverageCurrent( ),
performance specifications are at bq29311 regulated V_CC (V_(REG)) and a temperature of 0-70_C.
ManufacturerAccess( ) (0x00)
Description: This function provides writable command codes to control the bq2085 during normal operation
and pack manufacture. The following commands are available:
0x0001 Device Type instructs the bq2085 to return the IC part number; i.e., 2083 (0823h) to Manufacture
Access( ) so it can be read.
0x0002 Firmware Revision instructs the bq2085 to return the firmware revision.
0x0003 EDV Level instructs the bq2085 to return the pending end-of-discharge voltage level so it can be read.
0x062b SEAL instructs the bq2085 to restrict access to those functions listed in Table 3. The bq2085 completes
the seal function and clears ManufacturerAccess( ).
Purpose: The ManufacturerAccess( ) function provides the system host access to bq2085 functions that are
not defined by the SBD.
SMBus protocol: Read or write word
Input/Output: Word
RemainingCapacityAlarm( ) (0x01)
Description: Sets or gets the low-capacity threshold value. Whenever the RemainingCapacity( ) falls below
the low capacity value, the bq2085 sends AlarmWarning( ) messages to the SMBus host with the
REMAINING_CAPACITY_ALARM bit set. A low-capacity value of 0 disables this alarm. The bq2085 initially
sets the low-capacity value to Remaining Capacity Alarm value programmed in DF 0x02–0x03. The
low-capacity value remains unchanged until altered by the RemainingCapacityAlarm( ) function. The
low-capacity value may be expressed in either current (mA) or power (10 mWh) depending on the setting of the
BatteryMode( ) CAPACITY_MODE bit.
Purpose: The RemainingCapacityAlarm( ) function can be used by systems that know how much power they
require to save their operating state. It enables those systems to more finely control the point at which they
transition into suspend or hibernate state. The low-capacity value can be read to verify the value in use by the
bq2085 low-capacity alarm.
SMBus protocol: Read or write word
Input/Output: Unsigned integer-value below which Low Capacity messages are sent.
Units
Range
Granularity
Accuracy
BATTERY MODES
CAPACITY_MODE
BIT = 0
CAPACITY_MODE
BIT = 1
mAh at C/5
10 mWh at P/5
0–65,535 mAh
0–65,535 10 mWh
Not applicable
See RemainingCapacity( )
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