We are developing a very low power product. In some cases like not getting registered, PSM not being available, ... we want to drop the connection and go to a sleep state with a few uA energy consumption.
The problems we are facing:
- We are using AT+CFUN=0. The problem is that it can take very long. Does the nRF91 have a timeout to this?
Because at some point, we want to just give up deregistering nicely and shut down the modem to save on energy used. - Currently we're doing this "giving up on CFUN=0" after two full minutes. We then call nrf_modem_shutdown(). It appears that this call can also take more than a few seconds. Our devices reboot because that function took too long to return (watchdog).
So our questions are:
- How long can a AT+CFUN=0 at maximum take?
- Say we want to give up deregistering because AT+CFUN=0 is taking too long, can we do that and what is the best way?
- Say we don't want to use the modem for quite some time. Does it make sense to shut down the modem, or is CFUN=0 enough to be at the lowest possible power consumption?
Thank you.