Software Nss and Hardware Nss in SPI

Muzahir Hussain · ‎2018-02-11

Posted on February 11, 2018 at 19:03

What is Software NSS and Hardware NSS in SPI? Which Nss mode should we select?

Do we need to connect the NSS pin (between master and slave) in Software mode?

I read the NSS pin management in Reference manual, but I couldn't understand it.

Thanks!

#spi #stm-32

Bogdan Golab · ‎2018-02-11

Posted on February 11, 2018 at 20:22

Yestarday wanted to connect SPI based sensor to the STM32L152RE using HAL drivers (latest CubeMX, etc) and failed to use hardware NSS (the MCU was a MAster). Have no time to investigate it deeply and switched to Software NSS (activate / deactivate NSS through HAL_GPIO_WritePin(). So I am not the only one who has problem with using this feature;)