For a special usage, I need to disable both LO synthesizer and clock synthesizer to provide 18MHz source to them directly, the IF is 15.75MHz. I planned to take the following actions on AD9864/AD9874 evaluation board:
1. Install R14, R16, remove R19, R20, R22
2. Install R21, remove R17, R18, C34
3. Remove R28, C34, C35, connect pin 35 to ground directly
4. Set SPI register 0x00 bit[7:4] to 1.
Before I power on the board, I was wondering are the steps correct? Do I miss anything?
By the way, regarding the ad9874 SPI GUI, can I modify the parameters on GUI? I modified the parameters and click "write", when I read back the registers it seems it doesn't work, all the values are still from the configuration file.
Thank you very much.
The EVAL Board SCH:
The EVAL Board User Guide:
The SPI GUI: