bq20z80-V101
www.ti.com
SLUS625D–SEPTEMBER 2004–REVISED OCTOBER 2005
Host Watchdog
The bq20z80 can be configured to require the host system to communicate with the battery periodically, else the
battery disables charging and discharging. The Host Watchdog function is only active in Normal Power mode and
is disabled if the timeout period is set to 0.
If the bq20z80 does not receive any valid SMBus communications for a period of time ≥ DF:Host Watchdog
Timeout, the FETs are turned off, SBS.ChargingVoltage( ) and SBS.ChargingCurrent( ) are cleared to 0,
SBS.BatteryStatus( ) [TCA, TCA], SBS.OperationStatus( ) [XDSG], SBS.SafetyStatus( ) [HWDG] are set.
For normal recovery to be achieved, normal SMBus communications must be resumed. When this occurs, the
FETs are returned to the normal operating state, SBS.BatteryStatus(
) [TCA, TDA] are cleared,
SBS.ChargingCurrent( ) and SBS.ChargingVoltage( ) are set to the appropriate value per the charging algorithm
and SBS.OperationStatus( ) [XDSG] and SBS.SafetyStatus( ) [HWDG] are reset.
NAME
CLASS / SUBCLASS
FORMAT
VALID RANGE
SIZE (BYTES)
UNITS
DEFAULT VALUE
Host Watchdog Timeout
1st Level Safety / Host Comm (3)
Integer
0 to 255
1
s
0
19
TI [ TEXAS INSTRUMENTS ]
