nPM1300: Hard Reset When Charger Inserted?

[Chendi]

I would like to trigger a hard reset when valid voltage is first detected on VBUS.
How could I do this with no or minimal external components and without a complementary MCU?

"When a GPIO is used to control a load switch or LDO, it uses edges. When the GPIO toggles from LOW to HIGH, the switch or LDO turns ON (switch conducting). When the GPIO toggles from HIGH to LOW, the switch or LDO turns OFF."
https://docs.nordicsemi.com/bundle/ps_npm1300/page/chapters/core_components/loadsw/doc/frontpage.html

LDSW1GPISEL:
- INVERTED 1

LDSWCONFIG
- ACTIVE 1 Active discharge enabled

Would something like this work?
1. Detect a rising edge on VBUS
2. Invert the logic level to an LOAD switch
3. which could be used to pull SHPHLD down, causing a hard reset?

Thanks

[Priyanka]

Hi Senthil,

I am checking this internally and will get back to you.

-Priyanka

[Priyanka]

HI,

Guess that you will configure EVENTVBUSDETECTED as interrupt that would trigger the GPIO state change, or what would actually trigger the GPIO state change without MCU intervention?

This could work, but it is best to test with your configuration to make sure.

Things to consider:

- The pull-up on SHPHLD is 50kohm, so it is not very strong.

- The reset delay for SHPHLD reset is 10s. So it takes quite long time for the reset. That has to be considered from the system point of view, whether it is ok.

-Priyanka

[JONATHAN LL]

A standalone alternative is not supported, something needs to control the nPM1300 over TWI to for charging as an example. 

nPM1100 might be a better fit for you have you looked at it as a possible option ? 

Regards,
Jonathan

[Chendi]

Sorry, I tried to be minimal with my context but this has backfired! ...

I want to use nPM1300 with a MCU as part of normal operation.
But to potentially save on a dedicated hard reset button, I want to explore triggering a hardware reset when the charging cable is inserted - say if the MCU has crashed.

Thanks

[JONATHAN LL]

Thanks for the extra info, this clears up the inquiry. 

So you want to trigger a reset every time the charging gable is inserted? 

Regards,
Jonathan

[Chendi]

Exactly : )

... to trigger the HARDEST possible reset every time the charging gable is inserted

[JONATHAN LL]

You could use the watchdog timer to achieve a reset if the CPU has crashed, see https://docs.nordicsemi.com/bundle/ps_npm1300/page/chapters/core_components/timer/doc/frontpage.html#ariaid-title3, does this cover the situations you are trying to safe guard against?

Or do you still want to have a hard reset of the CPU chip when the USB charging cable is connected?

Regards,
Jonathan