DCM’s

Here is another great Xilinx App Note that sheds light on Digital Clock Managers available for Spartan 3 and 6 chips.

Digital Clock Managers (DCMs) provide advanced clocking capabilities to Spartan™-3 FPGA applications. DCMs optionally multiply or divide the incoming clock frequency to synthesize a new clock frequency. DCMs also eliminate clock skew, thereby improving system performance. Similarly, a DCM optionally phase shifts the clock output to delay the incoming clock by a fraction of the clock period. The DCMs integrate directly with the FPGA’s global low-skew clock distribution network.

via www.xilinx.com