This is a question about pin mux.
To use the SSI0 peripheral (for example) in 2-wire (legacy or advanced bi-spi), must the SSI configuration use the DAT0/DAT1 pins for MOSI/MISO, or can one use (for example) DAT1/DAT2.
As I read it, the datasheet is pretty clear about using DAT0/DAT1, and when I go to into the TI-RTOS code, the only use I see for the "portMOSI" pin in the SDSPI driver config (a layer on top of SSI) is for a specific SD-card init routine. There are no other uses for "portMOSI" in all of the RTOS, so I don't see how the peripheral would ever know that one intended DAT2 to be MISO.
The presence of that "portMOSI" item in the SDSPI driver config is the source of one engineer's belief that 2-wire SSI can be specified to use any of the 4 DAT0-3 pins for MOSI and MISO.
I'd appreciate any feedback on this. What's riding on this question is whether to put testing effort into a prototype board that is wired for DAT1/DAT2, and that at first crack doesn't function correctly. If the pin mux is simply wrong, we'll fix the board; if the pin mux is correct, then I'll keep troubleshooting.
Thanks,
Bob Cram
