Introduction - If you have any usage issues, please Google them yourself
-- Description : This core implements a SPI master interface.
-- Transfer size is 4, 8, 12 or 16 bits.
-- The SPI clock is 0 when idle, sampled on
-- the rising edge of the SPI clock.
-- The SPI clock is derived from the bus clock input
-- divided by 2, 4, 8 or 16.