no reloading context after power on

[davidBaselga]

I used LoraWan Basic on stm32Cube with STM32L082KZT6 and semtech SX1276IMLTRT.
Join, Uplink and downlink work correctly.

I would like the system not to make a "join" at each startup (power on).

I see backups in EEPROM, at startup during init I also see loading from the EEPROM but I cannot send any frame.
I don't understand why and I haven't found an example.

thanks a lot
David

[opeyrard]

Hi,

Only Devnonce and joinnonce are stored in non-volatile memory as requested by LoRaWAN standard.
The full LoRaWAN stack context is not stored in NVM.

[davidBaselga]

if I understand correctly, To not do a join after a restart I only need joinnonce and Devnonce, or do I need other data?

Thank you very much for your response

[opeyrard]

Hi,
In the current LBM implementation, you have to perform a new Join after a Reset.
The whole context of LoRaWAN is not saved.
We are studying the possibility to improve it (especially to support ABP) in the next release.
Many thanks,

[davidBaselga]

Thank you very much for these clarifications.

I succeeded in saving the context by making these modifications in the lower layers:

• I added the devAdr in the context (CONTEXT_LORAWAN_STACK)
• I added a function to write to fcnt_up: I have a special algorithm who save de fcnt_up only every 100 to limit writing in eprom
• on the SMTC_MODEM_EVENT_JOINED event, I added the key backup: smtc_secure_element_store_context(STACK_ID);

So on the reset event:

• I force the status to join: lorawan_api_set_join_status(STACK_ID, JOINED);
• I load the modem context: modem_load_modem_context();
• I load the keys: smtc_secure_element_restore_context(STACK_ID);
• and I load the new fcnt_up

[opeyrard]

Hi,
To be more LoRaWAN compliant, you could improve your code by saving the LoRaWAN/regional parameters (channel, Data rate, RX1 delay ...) sent by the network server.
Many thanks,