The device is capable of hardware reset to completely powercycle the
system. This is partcularly useful when a soft reset on the MCU or host fails to
work. A hardware reset needs to be possible in all SYS MODES.
There are a few ways a hardware reset occurs. A hardware reset will occur when:
- The HW_RESET clock expires when
the WATCHDOG_SEL is set to 0b01 or 0b10
- No I2C transaction occurs when
VIN is plugged in when the WATCHDOG_15_SENABLE is set to 0b1 within 15s
- EN_RST_SHIP is set to 2b11
- PB_LPRESS_ACTION is set to 2b11
and the button has been pressed for a duration set by MR_LP_LPRESS
Below is a sequence of events during a hadware reset:
- Turn OFF (if adapter is present)
input FET
- Turn OFF battery FET
- Engage pulldown on SYS
- Start the Autowake timer
- Once the Autowake timer expires,
disconnect the pulldown on SYS
- Reset all registers to default
(as in new power up)
- Turn ON battery FET and input FET
(if applicable).
At a time tRESET_WARN before the reset pulldown on SYS occurs, an
interrupt occurs to signify a hardware reset is about to occur.