With the P2 - using a AB1805 watchdog/rtc - I see there is a deep power down method. Would you be able to expand/confirm the method description please?
/**
* @brief Enters deep power down reset mode, using the EN pin
*
* @param seconds number of seconds to power down. Must be 0 < seconds <= 255.
* The default is 30 seconds. If time-sensitive, 10 seconds is probably sufficient.
*
* @return true on success or false if an error occurs.
*
* This method powers down the MCU and cellular modem by using a combination
* of the EN and RST pins. This super-reset is similar to what would happen if
* you disconnected the battery.
*
* It assumes that EN is connected to /nIRQ2 (PSW) on the AB1805 using an
* N-channel MOSFET and RST is connected to /RESET on the AB1805.
*
* After the deep reset finishes, the device will reboot and go back through
* setup() again. Calling getWakeReset() will return the reason `DEEP_POWER_DOWN`.
*
* This works even if the RTC has not been set yet.
*/
bool deepPowerDown(int seconds = 30);
EN being on the 3V3 power supply to the P2? Presumably EN must be pulled high and is then pulled low by nIRQ2 via the n-channel MOSFET. Could you provide a schematic snippet?
I am asking this with the knowledge that it is stated elsewhere that this isn't recommended to be used frequently because of the ungraceful shutdown. My aim is a full-power down reset of a P2 in an enclosure without exposing a battery switch through the case where all else has failed to clear a problem.