Hi,
Can I make a connection between SSP0 and SSP1 interface of the same MCBSTR9 board?
I tried, but I have some problem with NSS signal of the slave interface.
Could you give me some advice?
Note that the master normally have a slave select output pin, which you connect to the slave select pin of the slave.
In some situation, you use any GPIO pin on the master side to drive the slave select line of the slave. After all, a master may have multiple slaves that may need to be controlled individually to address which slave you currently wants to talk with.
While many better SPI controllers supports other protocols too, I haven't looked closer at the TI protocol. But at least for traditional SPI, you need to let the slave see a transition on the slave select signal to make sure that the slave is correctly synchronized with the data. A spurious noise bit on the clock signal will make the slave lose the bit synchronization and to be continuously out-of-sync until you either reset the SPI controller or toggles the slave-select signal off/on.