> Master - configure SPI port with SAME clock phase, mode and clock rate as
> the Slave device. Load data register with byte to send to Slave on SPI bus.

Note that on the slave device you don't have to set the clock rate--that's
what the clock WIRE is for...

> Wiring is as follows:
>
> Master          Slave
> DO ---------------DI
> DI  ----------------DO
> CLK--------------CLK
>
> DO = data out
> DI = data in
> CLK =clock
>
> Note how DO and DI are cross-wired for Master and Slave.
> Data is exchanged simultaneously, bit for bit.

Note that on Motorola CPU's, the pins are labeled MISO ("master in slave out")
and MOSI ("master out slave in"); the MISO pins should be wired TOGETHER as
should the MOSI pins.