nrf91-series

Activation of reset loop restriction

The modem counts all resets where the modem is not gracefully deinitialized with +CFUN=0. If modem deinitialization with +CFUN=0 is triggered before the predefined limit is reached, the reset counter is set to zero and the counting starts from the beginning. In modem firmware version 1.3.0, the limit is 5. In modem firmware version 1.3.1 and later, the limit is 7.

CAUTION:
CFUN=0 causes writing to Non-volatile Memory (NVM). When using CFUN=0, take NVM wear into account.

The counter is reset after modem initialization when a reset has not occurred in 60 s. This indicates that the device does not constantly reset after initialization and the counting can start from the beginning.

If the modem is activated after initialization and registration to network succeeds before 60 s has passed, the 60 s validation timer is restarted. When the timer expires, the counter is reset.

The activation of the reset loop restriction is notified with the %MDMEV: RESET LOOP AT notification after the modem's activation when the blocking starts or is still ongoing. A modem reset and deinitialization with +CFUN=0 removes the notification subscription and a new subscription is required after the modem is initialized.

Modem domain event notifications, including notifications of the modem reset loop restriction's activation, can be subscribed with the following %MDMEV AT command:

AT%MDMEV=1

For more information on the %MDMEV AT command, see Modem domain event notification %MDMEV in nRF9160 AT Commands or nRF91x1 Cellular AT Commands.