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SPI NSS configuration in STM32H753 custom board

hvs_learn
Associate II

I have the main MCU serving as the master in the spi communication whose primary job is to transmit data over SPI lines to two slaves. If I choose hardware NSS signal configuration the IOC file assigns a default pin as the NSS signal for that SPIx peripheral. I have a basic doubt as to whether it is better for me to do Software or Hardware NSS signal? If I choose hardware NSS signal the default pin can serve as CS for just one slave, how can I have multiple CS working with SPI bus, should I just GPIOs as the NSS signal lines? Or do it with Software NSS signals if so how is it done? I have not yet worked with SPI on STM32, only with Arduino so have no idea what is happening? The manual is a bit intimidating rn.

1 REPLY 1
JBias
Associate II

You are correct with using two separate signals for each CS and not using the hardware NSS line option (built into the SPI hardware)  So, you will be using a software command to turn on the CS  -- do the SPI transfer -- then a software command to turn off the CS. It would be something like this:

JBias_0-1737586445712.png