When I use SPORT1 for SPI transmission, how can I generate clock only when I send data ?

Hi . 

I use SPORT1 of BF533 for SPI transmission. I find that when I enable data transmission by

*pSPORT1_TCR1 = (*pSPORT1_TCR1 | TSPEN); ,

the clock will continue to be provided. I hope that the clock will be generated only when I transmit data. Can this be realized?