I received this customer question:
I have a question regarding the ADF9360-X series PLLs. In the datasheet for these devices It is stated that three bytes should be sent via SPI to configure the different registers on the device. When I send three bytes the PLL will not program properly. After using a logic analyzer on the demo board I discovered that the MCU that controls the PLL actually sends *four* bytes. After replicating this behavior I am able to successfully program the device. Any idea what is going on here?