1.The max7219 is an integrated serial input common cathode display driver that connects a microprocessor to an 8-digit 7-segment digital led display as well as to a separate bar chart display or 64 LEDS.

2.It includes a BCD encoder on the chip,a multi-path scanning loop,a segment driver and an 8 by 8 static ram to store each piece of data.

3.Only an external record is used to set the segment current of each led