Specifications:

• MAX7219 digital display control module 7 Segment Digital Tube
  
• This module is compatible with 5V and 3.3V microcontrollers.
  
• You you can use it for Arduino
  
• MAX7219 is an integrated serial input / output common-cathode display driver,
  
• which connects your microprocessor to a 7-segment digital LED display with 8 digits.
  
• Only three IO ports are used to drive the eight digit display.
  
• MAX7219 supports flicker free displays as well as cascading displays.

Wiring instructions(for example, it can connect any IO port,modified the Port Definition in the program):

• VCC: 5V
  
• GND: GND
  
• DIN: P00
  
• CS: P01
  
• CLK: P02