Step2: 7 Segment Display Pinout. Each one of the seven LEDs in the display is given a positional segment with one of its connection pins being brought straight out of the rectangular plastic package. These individually LED pins are labelled from a through to g representing each individual LED. The other LED pins are connected together and Inthis video, I will show you how to use a 4-Digit 7--Segment Display and guide you step by step on how to write the code. I will also show you how to displ Touse this display, we must connect GROUND to pin 3 and pin 8, then connect +5V to the other pins and make each of the individual segments light up. The diagram below shows the internal structure of the common cathode seven-segment display: In contrast, the common anode display is the opposite. In a common anode display, the positive terminal zmOC.