DCM loses lock on Virtex-4: It’s all about auto calibration

The whole story began when I decided to be kind enough to tell the Xilinx tools (ISE 9.2 in my case) that the Virtex-4 I’m targeting is a grown-up. Stepping 2, to be precise. I added CONFIG STEPPING = “2″; to the UCF file. It must have been one of those moments where I believed [...]