Hi All,
The write to register 0x13 is deliberate. User Map register 0x13 contains a read only register (Status 3) and a write only register. The write only register controls whether voltage is output to the external crystal.
I explain this in the following post:
How Do I Use an External Oscillator to Clock the ADV728x ?
I will update the ADV728x hardware manual in order to avoid this confusion in future.
Regards,
Robert Hinchy
Senior Applications Engineer,
Analog Devices Inc.