This PCB takes 8-bits of anode inputs (
dp) and 4-bits of cathode inputs (
C4) to display values on one of four 7-segment displays. The 7-segment displays are multiplexed: they share common anode pins and are individually selected through their cathode pins to display data. Current-limiting resistors are included on the board.
This PCB uses a multiplexed 7-segment display and 220 ohm current-limiting resistors.
Click for a larger version.