Touch screen can not work well when AD conveter works.

I am testing the Beaglebone black C and LCD displayer 4DCAPE-70T that is pruced by 4D-systems now. If ADconveter that is installed in the beaglebone black C works, the touch panel that is provided in 4DCAPE-70T works very slowly and sometimes CPU halts at all.

For example

root@beaglebone: ~# echo cape-bone iio>/sys/devices/bone_capemgr.*/slots

root@beaglecone:~# cat /sys/devices/ocp./helper./AIN4


root@beaglebone:~# cat /sys/bus/iio/devices/iio! :device*/in_voltage7_raw



I am eager to work out this problem. Please suggest.