I have an external 10 MHz signal from 0 to 1.2V (sinusoidal) as input. When the eval board is started it comes with message that Ref is absent. I have both 3.3V and 1.8V at the header for power. I also have the jumper set to select the external reference.
In the chip level window, I can set the reference clock to 10 MHz and load it. After a read, it still reads 10 MHz. I set a multiplier and load it. But upon a read it always comes up as disabled.