Bug in Low-Level driver LL_SPI_ReceiveData8 for STM32L0, STM32L4, STM32L5 and possibly others

[SOfne.1]

Affected driver libraries: STM32Cube_FW_L5_V1.4.0, STM32Cube_FW_L4_V1.16.0, STM32Cube_FW_L0_V1.11.2 and possibly other device driver libraries based on the same SPI peripheral

File: stm32yyxx_ll_spi.h (Replace yy by L5, L4, F0, ...)

Functions affected: LL_SPI_ReceiveData8

Bug: Current implementation performs a 16bit read access to DR register and then casts the result to 8 bits. This leads to unexpected behavior. For example STM32L5 supports data packing, when SPI data frame size is less than or equal to 8 bits and 16 bits are read. In this case, the current implementation of LL_SPI_ReceiveData8 reads two (packed) bytes from DR register and discards the second one when casting the read result to 8 bits.

Correct implementation: Cast pointer to DR register to uint8_t before access.

__STATIC_INLINE uint8_t LL_SPI_ReceiveData8(SPI_TypeDef *SPIx)

{

  return *((__IO uint8_t *)&SPIx->DR)

}

[Imen.D]

Hello @SOfne.1​  and welcome to the STM32 Community :)

Thanks for pointing out this issue.

I am checking it internally and I will come back to you with details about corrective actions we will take, or explanation if needed.

Imen

[Imen.D]

​Hi @SOfne.1​ ,

This issue will be fixed in the coming release of STM32CubeL5 MCU package.

Thanks for your contribution.

Imen

[SOfne.1]

Hi @Imen DAHMEN​ 

Thanks for your fast response. Will this issue be fixed in the next releases of STM32CubeF0 and STM32CubeL4 MCU package, too?

Best regards,

Sebastian

[Imen.D]

Hi @SOfne.1​ ,

I think this is already fixed in the release of STM32CubeF0 V1.11.0.

I reported this issue internally to check and fix all impacted series.

Thanks for your feedback.

Imen

[SOfne.1 · Accepted solution]

Hi @Imen DAHMEN​ 

Thank you.

As you can see in the corresponding git repository for STM32CubeF0 firmware package this issue is still present in STM32CubeF0 V1.11.2.

Best regards,

Sebastian

[Imen.D]

Hi @SOfne.1​,

You are right, only LL_SPI_TransmitData8() is correct in the latest CubeF0. I've escalated this issue to correct LL_SPI_ReceiveData8() API.

The same correction will be performed for all impacted series.

Imen