Sport issue Between ADSP-SC587 and ADSP-BF561

Hello,

ADSP-SC587 interfaced with ADSP-BF561 through SPORT in our custom board, issue is when we set clock frequency 1 MHz communication between the processor is fine. But when we increase  the clock frequency, clock is getting deteriorated. Our requirement at least it should operate at 10 MHz speed. Please suggest, its urgent.

In one of our  custom board SPORT between ADSP-BF536 and BF561 operated at 10 MHz working properly.