STM32WB55RGV6 Can pin PC15 be used as the NSS(software) for the SPI bus? Pin PC10 and PC6 are ok. But pin PC13,PC14,PC15 doesn't work.

[Lep]

My configuration is shown below:

 gpioinitstruct.Pin  = SD_CS_PIN;

 gpioinitstruct.Mode  = GPIO_MODE_OUTPUT_PP;

 gpioinitstruct.Pull  = GPIO_PULLUP;

 gpioinitstruct.Speed = GPIO_SPEED_FREQ_LOW;

 HAL_GPIO_Init(SD_CS_GPIO_PORT, &gpioinitstruct);

[TDK]

> Can pin PC15 be used as the NSS(software) for the SPI bus?

Yes, it's a GPIO pin and you can toggle it.

PC15 has limited current capability, but shouldn't be an issue for a CS pin.

See notes in datasheet on PC15. RTC settings will override GPIO settings.

Also ensure PC15 on your board is free and not acting as OSC32_OUT.

[Lep]

LSE is disable.My test includes P_Nucleo_WB55 and a TF card module.I use FATFS in spi mode.I use the example program which named FatFs_uSD_Standalone.I just changed the SD_CS_PIN and the gpio configuration. I don't kown why it doesn't work.

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When i use pin PC10 and PC6, it's work well.But when i use pin PC13, PC14, PC16, it's doesn't work in same gpio configuration:GPIO_MODE_OUTPUT_PP, GPIO_SPEED_FREQ_LOW,GPIO_SPEED_FREQ_LOW.

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I have see notes in datasheet: LSE is disable and the gpio's speed is low.`Is there anything else I need to do?

[Lep]

PC13 PC14 PC15(NOT PC16)

[TDK]

PC14 and PC15 aren't connected to an output on that board by default. Need to close some solder bridges and remove the LSE crystal.

 

 

PC13 should work as far as I can tell, if it's not being used by the RTC.

[Lep]

Thank you.This problem has been bothering me for several days:beaming_face_with_smiling_eyes: