AD5686 problems with timing

Hello, I'm Nikolai Ehrhardt from Germany,

I got problems with the timing of the AD5686,

I'm giving a falling flank on the Sync line, then the ATmega168 starts to transmit the dataword via USART in MSPIM beginning with 0011 for LDAC independant commands. But the DAC does not receive or work with the data. The Outputs keep low.

Greets & Thanks