new sketch using the Lowpower mode with LoraWan connection

[FRASTM]

This new sketch is configuring the stm32wl55 nucleo board to enter lowpoer (stop2) mode after a lorawan connection An Alarm (ALARM_A) is programmed to go to sleep mode for a period of time (atime value in milliseconds). On wakeup a packet is sent and goes to sleep again.

[FRASTM]

Once the connection is done (after the modem.joinOTAA), the AlarmMatch callback function is called

18:15:10.903 -> Start
18:15:31.902 -> Joined
18:15:31.902 ->   Alarm Match: 0 times.
18:15:46.187 -> Queued packet
18:15:46.187 -> Sent packet
18:15:46.187 ->   Alarm Match: 3 times.
18:15:56.584 -> Queued packet
18:15:56.616 -> Sent packet
18:15:56.616 ->   Alarm Match: 5 times.
18:16:04.584 -> Queued packet
18:16:04.584 -> Sent packet
18:16:04.584 ->   Alarm Match: 7 times....

[FRASTM]

After LoraWan joined, the nucleo_wl55 is entering low power deep sleep mode (STOP2) for 60 seconds (TX_INTERVAL) and send a packet with current RTC calendar.

13:56:16.927 -> Start
13:56:25.178 -> Joined
13:56:25.178 ->   Alarm Match: 0 times. deepSleeping now ! 
13:57:25.201 -> 09/04/2023 - 15:31:58
13:57:33.198 -> Sent packet
13:57:33.198 ->   Alarm Match: 1 times. deepSleeping now ! 
13:58:33.202 -> 09/04/2023 - 15:33:06
13:58:39.596 -> Sent packet
13:58:39.596 ->   Alarm Match: 2 times. deepSleeping now ! 
13:59:39.627 -> 09/04/2023 - 15:34:12
13:59:46.014 -> Sent packet
13:59:46.014 ->   Alarm Match: 3 times. deepSleeping now ! 
14:00:46.025 -> 09/04/2023 - 15:35:18
14:00:51.226 -> Sent packet
14:00:51.226 ->   Alarm Match: 4 times. deepSleeping now ! 
14:01:51.239 -> 09/04/2023 - 15:36:24
14:01:56.442 -> Sent packet
14:01:56.442 ->   Alarm Match: 5 times. deepSleeping now ! 

Measuring power consumption of the nucleo_wl55jc (on JP1 with STLInk USB plug) --> LED is blinking on one period