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MQX4.1 Kinetis K22 SPI MUX questions

Question asked by Angelo Quattrociocchi on Jul 24, 2014
Latest reply on Jul 28, 2014 by soledad

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?