NEC Barracuda Service Manual page 40

1.2.5 Battery Fault
There are two kind of battery fault events which can force the system shutdown to prevent data lose .
1.2.5.1 Battery capacity low
While battery capacity below 3.4V , the hardware comparator will assert signal BAT_FAULT_IRQ# to interrupt
CPU to save data to SDRAM and execute SDRAM self-refresh command , then assert BAT_FAULT_EN to enable
Hardware Battery Fault mechanism (SA1110 ) which force system shutdown .
1.2.5.2 Battery cover lose
Since Capricorn battery is swappable , user has the way to access battery . The battery mechanical cover must be
monitored to ensure Capricorn battery is connected well without battery dropout problem . while battery cover be
removed , that will release one switch button and cause the signal BAT_FAULT_IRQ# be active , then the routine
will be the same as battery capacity low event .
Barracuda PDA Maintenance
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