I have got EVAL-AD7656-1SDZ and I am performing the data acquisition via the serial interface. I have changed the LK connections in order to use the serial interface. I am testing two test cases. In the first one, I shorten all V1…V6 so I do expect all data inputs to be zeros. But DATA_A … DATA_C are HIGH all the time, as you can see on Picture screen92.png. When I open jumpers for V4, V5 and V6, my DATA_A … DATA_C looks like the output on Picture screen91.png.
The strange behavior of data inputs could be caused by my misconnection of the evaluation board. Once, I have connected the serial interface cable, but I did not connect the power input. My colleague told me that this could lead to damage of the 7656 chip.