Using an USART in SPI master mode, which pin should be the NSS?

[FBIZA.1]

When using an STM32L0 USART in SPI master mode, if the Slave needs a low level at the beginning of the frame and a high after the data byte, can I use any GPIO as NSS master to output this levels?

[Imen.D]

Hello @FBIZA.1​ ,

I recommend you to review the pins assignment in the datasheet related to your product.

Best Regards,

Imen

[waclawek.jan · Accepted solution]

>  can I use any GPIO as NSS

Yes.

> USART in SPI master mode

I wonder, where this confusing terminology came from. It's *synchronous* mode of the USART, that's why the S in USART...

JW

[FBIZA.1]

I took this terminology from this ST presentation <USART used as SPI Master (page 14)>. But they don't specify anything about which pin should apply the NSS signs for the slave.

Thanks for your clarifying answer!