B-L072Z-LRWAN Discovery Kit - App using Standby mode, no RAM retention

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Hi all,

we are currently deciding on the right OS for a project we are working on and have come to some questions regarding the low power capabilities of RIOT.

Our Dev platform: -> STM32 LoRa and Sigfox Discovery kit (B-L072Z-LRWAN1, https://www.st.com/en/evaluation-tools/b-l072z-lrwan1.html)

Most of the time the MCU should be in standby mode to have achive the lowest current consumption possible. But in that mode everything in RAM is lost. That means we would have to save the LoRaWAN configuration and approx. 250 byte of our own data to flash.

Our question is: How does RIOT handle the standby mode?

  • Do we have to rewrite the LoRaWAN stack?
  • Will our application restart, when using standby or is program data, counter, etc. saved and our app will continiue where it left?
  • Might custom firmware be the better choice? There is no parallelism in our app and we won’t need the console.

Thank you and with best regards, Marcel Maas

Low power modes -> AN445 (https://www.st.com/content/st_com/en/products/microcontrollers-microprocessors/stm32-32-bit-arm-cortex-mcus/stm32-ultra-low-power-mcus/stm32l0-series/stm32l0x2/stm32l072cz.html#resource)

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Our question is: How does RIOT handle the standby mode?

There is support for multiple MCUs, but you will likely need to add extra some code to address your peripherals.

- Do we have to rewrite the LoRaWAN stack?

The Semtech stack is supported as a package, and a natve RIOT implementation is being worked on.

- Will our application restart, when using standby or is program data, counter, etc. saved and our app will continiue where it left?

You can achieve that with a really small patch to the Semtech wrapper. I have a working demo for an Atmel SAMR34 (which is a SAML21 MCU coupled with a Semtech 1276 radio module, on the same die):

   GitHub - ant9000/lora-leaf: SAMR34 LoRa sensor node firmware, made with RIOT

- Might custom firmware be the better choice? There is no parallelism in our app and we won't need the console.

In my experience, RIOT gives you a jump start and provides many useful tools - you won't lose anything by relying on it.

HTH, Antonio

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Hi,