An integrated serial input/output common-cathode display driver that connects your microprocessor to an 8-digit 7-segment LED display. This digital display control module is compatible with Arduino. Operates with 5V or 3.3V microcontrollers. Uses only three IO ports to drive the eight-digit display. Supports flicker-free and cascading displays. PCB features fixed copper studs at the four corners to help prevent short circuits. Wiring instructions (programmable – IO ports can be redefined in code): VCC to 5V, GND to GND, DIN to P00, CLK to P02, /CS to P01. The display is a 0.36-inch 4-digit integrated common-cathode LED module. Note: Do not reverse VCC and GND, as this may damage the chip. The 8051 MCU P0 port requires a pull-up resistor; if your device lacks one, connect to another port. Material: PC + metal Color: Blue Package Contents: 4 x 8-digit digital display modules Note: The package includes only the items listed above. Other accessories are not included. Note: Lighting and display settings may cause slight color variations. Measurement error allowance: +/- 1-3 cm.