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I am designing hardware using STM32H7. I would like to connect three power monitor devices to SPI4 of MCU as slave devices, but SPI4 has only one NSS(slave select) pin. How should I connect these multi slave devices to SPI4 of MCU?

EAbra.3
Associate II
 
4 REPLIES 4
LCE
Principal

Use other GPIOs for NSS, pull them low before each SPI transaction, back to high again when done.

EAbra.3
Associate II

Thank you very much for the prompt reply. Can I use any of the I/O pins for NSS or is there any particular GPIO pins for the same?

EAbra.3
Associate II

I have one more question that, once I connected the GPIO pins as NSS, later I should control these pins using software. Am I right or not?

Yes, you have to control these pins "manually":

GPIO LOW

do SPI stuff

GPIO HIGH