My AD9837 goes into an error state by doing frequency sweeps. The problem occurs at random frequencies and sometimes it passes more sweeps without interruption.
I am not doing the sweep like described in AN-1044.pdf but with setting each frequency individualy every 20ms. I am controlling the DDS with a PIC Microcintroller and the reference clock is 4Mhz.
When the DDS is in the error state i have to restart it completly by disconecting it off power and wait for some while and after that it works.again until the next error state.
I can't find out how to solve that problem or what could be the cause for it.
This is how the error state looks like: