The MAX7219 is an integrated serial I/O common cathode display driver that connects a microprocessor with an 8-digit, 7-segment digital LED display, as well as a bar graph display or 64 independent LEDs. It includes an on-chip B-type BCD encoder, multiple scan loops, segment word drivers, and 8*8 static RAM to store each piece of data. There is only one external register used to set the segment current for each LED. A convenient four-wire serial interface connects all common microprocessors. Each data can be addressed during the update without overwriting all the displays. The MAX7219 also allows the user to choose whether or not to encode each piece of data. The entire device contains a 150 A low power shutdown mode, controls analog and digital brightness controls, a scan limit register that allows the user to view 1 to 8 bits of data, and a detection mode that turns on all LEDs. < p>Only 3 IO ports are needed to drive 1 dot matrix! Flicker-free dot matrix display! Cascading is supported! Module Parameters: 1. A single module can drive a common 8*8 2 cathode array. Module working voltage: 5V 3. Module size: length 12.8cm X width 3.2cm X height 1.3cm 4. With 64 mounting screw holes, the hole diameter is 3mm 5. The module has an input and output interface, supporting multiple modules in cascade Wiring instructions: 1. The left side of the module is the input port and the right side is the output port. 2. When controlling a single module, you only need to connect the input port to the CPU 3. When multiple modules are cascaded, the input terminal of each module is connected to the CPU, the output terminal is connected to the input terminal of the second module, the output terminal of the second module is connected to the terminal d input of the third module, and so on... Let's take the example of microcontroller 51: CCV5V < p>GNDGND DINP2.2 CSP2.1 CLKP2.0 Shipping List: 1. MAX7219 four-in-one matrix module (the finished product, with dot matrix, has been tested) 2.20CM DuPont Line 5P