SPI max. rate

The serial port max. rate for SPI operation mode is SYSCLK/8. Using the bit rate generator equation, FBRG = FXTAL/(2*(N+1)), i could only set the SPICLK to max. 1.8432MHz using an external 18.432MHz crystal. Is there any other registers that i should initialized in order for the SPICLK to operate at its max rate, i.e SYSCLK/8 = 5.53MHz ??

That’s all to be done.