Other Parts Discussed in Thread: CDCE62005
Hi:
I'm a using spartan6 to control cdce62005, I first tried with the default configuration in internal eeprom, I used a single ended aux_in 25Mhz clock ,and I can detect correct 125Mhz output ,then I tried with sec_ref, I used LVDS 25Mhz DC connection, I changed register 5 from 101C0BE to 101C8ff to suit my case, then I detected 109Mhz output at output4, and the pll_lock is always low.
I doubt it's because I didn't do vco calibration, so I write the new value of register 5 to eeprom, in this case the start up calibration will based on the LVDS input, but I still get 109Mhz output.
I also tried to directly output the sec_ref to output4, then I only get a high but not a clock.
It seems like my 25Mhz lvds clock is not recognized by cdce62005, could you please tell me how I can debug this ?
By the way, can I use LVCMOS in sec_ref without a 1K resistor connects to ground at the negative input pin ?
Thank you very much for your kindly help.
