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9 years, 3 months ago.
spi Nss
Hi I am newbie, I am using nulceo f401re but I am confused with NSS1 pin. I test it with multitester but both of NSS seems didnt have any connection. 
Can anybody tell me which one is the real NSS1 or both of NSS1 is true? thank you /media/uploads/younatan/xnucleo64_revc_f401re_mbed_pinout_v2_arduino.png.pagespeed.ic.x_9k38l1rt.webp
1 Answer
9 years, 3 months ago.
The NSSx pins are typically only used when the nucleo is an SPI slave. They become active when you select them in the SPI Slave constructor. Which of the possible pins it is depends on your selection in the constructor, but the NSSx must match the SPI engine x that used for the Slave function. So NSS1 for SPI1 SCLK, MISO and MOSI. In the SPI master mode any pin can become the CS output pin.