DS90UH949/DS90UH940 SPI communications clock frequency

Hi teams :

When we debug DS90UH949/DS90UH940 SPI communications, the specification wrote that SPI CLK is a high-speed mode when SPI is written. When SPI reads mode, SPI CLK is a low speed mode. However, neither high speed nor low speed mode is shown on the specification, and what is the SPI clock frequency.

Thanks & Regard