SigFox stack for B-l072Z-LRWAN1 - warnings when compiling cubeMX examples

[Aurelian Lazarut]

I'm using the examples for SigFox stack for B-l072Z-LRWAN1 - with Atollic Studio as IDE

After converting the project from SW4STM32 to Atollic (there is a project import built in) - when compiling the code for the push_button application I'm getting a dozen warnings like

/../../../../../../../Drivers/STM32L0xx_HAL_Driver/Inc/stm32l0xx_ll_spi.h:1133:3: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]

  *((__IO uint16_t *)&SPIx->DR) = TxData;

Are these these warnings harmless? They look pretty serious to me.

Thanks,

Aurelian

PS- the board hangs when trying to transmit.

[Aurelian Lazarut]

Just to add more info

The examples for LoraWan are compiling and working out of the box (same IDE same procedure for importing the project from SW4STM32 int Atollic TrueStudio IDE) - the B-I0072Z-LRAN1 works no problem, hardware is ok, but the Sigfox examples are not. Maybe someone from ST/Murata wants to look into this one.

How to reproduce -

Download stock STM32CubeExpansion_SFOX_V1.1.0

Import the Sigfox_pushbutton example into Atollic TrueStudio for STM32 (V9.0)

Chose the STM32L072 as target

Compile

Aurelian

[Tesla DeLorean]

>>Are these these warnings harmless? They look pretty serious to me.

This one is just the stupid GNU/GCC compiler. The explicit casting is to force a 16-bit access to the register.

#FashionPolice​ 

[Aurelian Lazarut]

maybe you're right - but the examples are hanging when trying to transmit a Sigfox packet (and I'm not willing to touch /STM32L0xx_HAL_Driver/Inc/stm32l0xx_ll_spi.h just to keep GCC happy.

It could be unrelated and the Sigfox transmission is hanging for a different reason.

More info -

I switched the IDE to the SW4STM32 (the example provided is for this IDE) - and the warnings are still there.

The good news is the warnings are harmless.

The problem was hardware - the B-L072zlrwan1 has some hardware links to be soldered in order for the Sigfox example to work (it in the docs on the bottom)

these links are

SB26 (requires soldering)

SB13 (requires soldering)

Jumper J9 to be on 1-2 position closed

This is clarified on the following doc at page 26

https://my.st.com/content/ccc/resource/technical/document/user_manual/group0/d6/6e/d3/e4/72/90/49/bf/DM00406670/files/DM00406670.pdf/jcr:content/translations/en.DM00406670.pdf

Have Fun,

Aurelian