Description:
MAX7219 is an integrated serial input / output common-cathode display drivers, which connects the microprocessor and 8 bit 7-segment digital LED display, you can also connect a bar graph display or 64 separate LED. Includes an on-chip type B BCD encoders, multi-channel scanning loop, segment word driver, but also a 8x8 static RAM that stores each data. Only one external register is used to set the current of each LED segment.
A convenient four-wire serial interface can connect all common microprocessor. Each data can be addressed in the update without rewriting all displays. MAX7219 also allows the user to select each data encoding or no coding.
The entire device includes a 150μA low-power shutdown mode, analog and digital brightness control, a scan-limit register allows the user to display 1-8 bit data, there is an all LED light detection mode.

Feature:
Digital tube is 0.36 inch 4-bit integrated cathode digital tube
Common cathode
Only need three IO ports can drive 8 bit digital tube
The module compatible of 5V / 3.3V microcontroller (51 / AVR / STM32...)
PCV board four corners of the fixed copper stud, which can effectively precent short circuit accidents happen
Wiring instructions (a program, for example, you can pick any IO port definition can be modified in the program): VCC to 5V, GND to GND, DIN to P00, CLK to P02, CS to P01

Note:
VCC and GND do not reversed, it would burn the chip.
51 MCU P0 port requires pull-up resistor, if your device does not have a pull-up resistor can be connected to other ports data lines.

Packing List:

4 * MAX7219 8 bit digital display module