SPI_NSS_Hard or SPI_NSS_Soft for only one slave

[nemisha]

Posted on October 15, 2015 at 13:27

Hi ,

I have an SPI program running successfully between two stm32f4 discovery boards using SPI_NSS as SPI_NSS_Soft. Some discussions on Stm32f4 SPI say that SPI_NSS_Soft has to be used when only one slave. Does that mean that when only 1 slave , we are not allowed to use SPI_NSS_Hard ?

But if we can use SPI_NSS_Hard then , what would be the difference in the configuration of the pins for sck , miso , mosi and nss on the master and on the slave side?  

Thank you so much.

#stm32f4 #discovery #spi #device

[waclawek.jan]

Posted on October 15, 2015 at 14:08

NSS_Hard implies to use one extra pin on both mcu. Do you want to spend a pin unnecessarily?

JW

[nemisha]

Posted on October 15, 2015 at 14:21

Hi,

Thank you for replying . Yes you are right. It makes no sense to waste a pin. But was just curious to if with only one slave NSS_Hard could be used.

Thank you!