I want to use XADC to sample 3 external analog inputs but the problem is that it can only sample internal signals like temperature or VCCs. When an external signal (of about 800 mV) is fed to VN/VP pins or auxiliary channel 0 or 8 at the XADC header, no data is captured by XADC. By the way, what is the correct way to connect an analog input to VN/VP or to any of the auxiliary channels.
FYI, I use AXI XADC 1.00a IP following the PlanAhead flow and XADC API driver in SDK to access XADC in simultaneous sampling mode (I have to remove MUXADDR, CONVST, and ALARM signals of the IP because PlanAhead won't generate bit stream with these signals hanging around).
