Tool = ISE 8.2i Target = Spartan 3 xc3s400-4tq144
I'm using an external 50 MHz oscillator and a single DCM to generate clocks of 50, 100 and 200 MHz. I would like to change this to 50, 90 and 180 MHz from the same external oscillator. I tried this using two DCMs and the timing analysis report went crazy! I think this is because the clock edges from a single DCM are all synchronised, but now I have routing delays which cannot be cancelled by the DLL. How do I stop the tools from checking paths between different clock domains?