PLL Reconfiguration problem on Cyclone3

Hi Videoman,

It seems pretty clear that you are losing the clock you are using for reconfig, right when you reconfigure the PLL. There is no guarantee that you keep getting a valid output from a PLL when you reconfigure it -- clocks stop, it loses lock, you might get glitches or runts, you might not get enough clock pulses to completely shift the scan chain into the PLL and it will hang, etc.

Is there any way you can get an independent clock that is not from a quartz crystal ? For instance, maybe add a second PLL to the design that takes 125 MHz down to 72, which is never reconfigured. Some sort of system housekeeping clock that is unrelated to the video of the moment.