1.Should I connect all Analog Discovery 2's ground to my development board? or one ground to be connected is ok? 2.I already sperate all wires connection, but the spike still appears. 3.Twist the signal wires with a ground wire. Did you mean this one? If so, can I do it with dupont line or it has to use special wire? And which side should I use twist wire? The Master side or oscilloscope side or both? By the way, I observe chip select line from oscilloscope and there is the