I'm working on a custom board based on the K21F120M tower board, and I'm not seeing the expected activity on the SPI bus. I think it is related to the pin MUX selections for the SPI but I'm not sure where that's defined. I'm using SPI0 on pins 93-96 (100pin package), but I'm not sure if the MUX options are set correctly, or how you even define which pins to use.
From _bsp_dspi_io_init () in init_gpio.c, it seems that for SPI0 it is defining I/O pins D0-D3, which is the same ones used on the tower board and also the ones I'm using, but it doesn't seem to work right. Am I missing something?
I'm also not clear about whether I should have DSPI0_USE_DMA selected. Are BSPCFG_DPSI0_USE_DMA and BSPCFG_ENABLE_SPI0 mutually exclusive? When they refer to DSPI in the MCU reference manual, does this mean DMA SPI?