STM32WB55 GPIO alternative SPI2(GPIO_AF3_SP2 vs GPIO_AF5_SPI2).

[Lep]

STM32WB55RGV6 connects ADS1299 by spi. And I choose spi2. There are three signas miso\ mosi and sck. SPI2 has two alternative: GPIO_AF3_SP2 and GPIO_AF5_SPI2.

① STM32CUBEMX automatically generated miso(GPIO_AF3_SP2), mosi and sck(GPIO_AF5_SPI2).Initialization is ok, but no data.

② All ​GPIO_AF3_SP2. Initialization is failed and application crash.

③​ All ​GPIO_AF5_SP2. Successfully.

Although the result is good, I do not understand why��

[waclawek.jan · Accepted solution]

Which pins?

Look at the Alternate functions table in the datasheet to determine, which AF number to use for each pin.

For example:

 

JW

[Lep]

Thank you,I found the error,SCK(PD1), GPIO_AF5_SPI2.