The constraint pin of the clock given in the reference manual is K4. But when I wrote a simple D flip flop code giving this constraint pin, the D Flip Flop didn’t function as expected. So is K4 the correct clock pin or not?
Are you using the Zynq PS or is this a PL only design?
If using PS, you could verify your design using a PS to PL clock.
The 125 MHz clock you are using is differential. K4 is only for the P side. Did you try to connect it using both P and N pins as a differential clock?
Cathal