1.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 8×8 static RAM that stores each data. Only one external register is used to set the current of each LED segment.

2.A convenient four-wire serial interface can connect all common microprocessor. Each data can be addressed in the update without rewriting all displays. It also allows the user to select each data encoding or no coding.

3.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.