I'm trying to figure out SPI operation in the Microchip C Compiler. As I
understand it, writing outgoing data to SSPBUF causes that data to be
loaded into  SSPSR, which then shifts it out. As data is being shifted
out, input data is being shifted in to SSPSR. On completion of the shift
in and out, the received data in SSPSR is put in SSPBUF so it can be
read. So far so good.
        Looking at the C compiler library documentation on the SPI library, it
LOOKS like BOTH WriteSPI and ReadSPI initiate an SPI bus cycle. It seems
to me that only WriteSPI should do that. ReadSPI would then pick up the
data received during the previous write. How does this actually work?
Actually, I could imagine a function called SPIrw that would have a
prototype of

unsigned char SPIrw (unsigned char DataToSend)

You'd pass it the data to send and it would return the received data.
But, that doesn't seem to be how it works.  So, how DOES it work?

Thanks!

Harold



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