1. MAX7219MAX7219 is an integrated serial input/output common cathode display driver. It is connected to a microprocessor and an 8 digit 7 segment LED display. It can also be connected to a bar graph display or 64 independent LEDs. It includes an on chip B type BCD encoder, multi channel scanning loop, segment word driver, and an 8*8 static RAM for storing each data. Only one external register is used to set the segment current of each LED. 2. Design compactA convenient four wire serial interface can be connected to all general purpose microprocessors. Each data can be addressed without updating all displays when updating. MAX7219 also allows users to choose to encode or not to encode each data.The entire device contains a 150A low power shutdown mode, analog and digital brightness control, a scan limit register allows the user to display 1 8 bits of data, and a detection mode that allows all LEDs to emit light. 3. SpecificationsA single module can drive an 8*8 common negative dot matrixModule working voltage: 5VModule size: length 12.8 cm X width 3.2 cm X height 1.3 cm With 64 fixing screw holes, hole diameter mm Module with input and output interface, support multiple modules cascadeOnly 3 IO ports are needed to drive 1 dot matrix! No flashing when dot matrix display! Support cascading. 4. Wiring InstructionsThe left side of the module is the input port, and the right side is the output port.When controlling a single module, only need to connect the input port to the CPU.When multiple modules are cascaded, the input of the first module is connected to the CPU, the output is connected to the input of the second module, the output of the second module is connected to the input of the third module, and so on.