8.3.6.3 Interrupt to Host
In some applications, the host does not always monitor the charger operation. The INT pin notifies the system host on the device operation. By default, the following events will generate an active-low, 256-µs INT pulse.
- Good input source detected
- VVBUS < VVBUS_OV threshold
- VVBUS > VPOORSRC (typ. 3.7 V) when IPOORSRC (typ. 30 mA) current is applied (not a poor source)
- VBUS_STAT changes state (VBUS_STAT any bit change)
- Good input source removed
- Entering IINDPM regulation
- Entering VINDPM regulation
- Entering IC junction temperature regulation (TREG)
- I2C Watchdog timer expired
- At initial power up, this INT gets asserted to signal I2C is ready for communication
- Charger status changes state (CHRG_STAT value change), including Charge Complete
- TS_STAT changes state (TS_STAT any bit change)
- VBUS over-voltage detected (VBUS_OVP)
- Junction temperature shutdown (TSHUT)
- Cell over-voltage detected (CELLOVP)
- Cell over-voltage detected (HS_OV or LS_OV)
- Charge safety timer expired
- A rising edge on any of the *_STAT bits
Each one of these INT sources can be masked off to prevent INT pulses from being sent out when they occur. Three bits exist for each one of these events:
- The STAT bit holds the current status of each INT source
- The FLAG bit holds information on which source produced an INT, regardless of the current status
- The MASK bit is used to prevent the device from sending out INT for each particular event
When one of the above conditions occurs (a rising edge on any of the *_STAT bits), the device sends out an INT pulse and keeps track of which source generated the INT via the FLAG registers. The FLAG register bits are automatically reset to zero after the host reads them, and a new edge on STAT bit is required to re-assert the FLAG.