MMCSD/SPI clocking signals on J15 expansion connector

Hi, I want to make a medium wave AM radio receiver. For AM demodulation I will use a waveform generator AD5932, that I want to programm with my C6748 LCDK (456MHz). I will connect it via expension connector J15. I need two clocking signals for SPI (up to 40 MHz) and for clocking of AD5932 (50 MHz ideally). I have two questions:

1) What is the value of  function clock frequency from equation: (spruh79a,page 1197)

memory clock frequency = function clock frequency/(2 × (CLKRT + 1))

2) May I use MMCSD_CLK for SPI "clocking" instead of SPI0_CLK?

Thanks for your answers.

Petr Duga