MAX7219 is an integrated serial input/output common cathode display driver that connects a microprocessor with an 8-bit 7-segment digital LED display, as well as a bar chart display or 64 independent LEDs. It includes an on-chip B-type BCD encoder, multi-channel scanning circuit, segment word driver, and an 8 * 8 static RAM for storing each data. There is only one external register used to set the segment current of each LED.
A convenient four wire serial interface can connect all general-purpose microprocessors. Each data can be addressed without rewriting all displays during updates. MAX7219 also allows users to choose whether to encode or not to encode each data.
The entire device includes a low-power shutdown mode of 150 μ A, analog and digital brightness control, a scan limit register that allows users to display 1-8 bit data, and a detection mode that causes all LEDs to light up.
Only 3 IO ports are needed to drive 1 dot matrix! No flicker during dot matrix display! Support cascading!

Product parameters
1. A single module can drive an 8 * 8 cathode dot matrix
2. Module operating voltage: 5V
3. Module size: Length 13cm X Width 6.4cm X Height 1.3cm
4. Equipped with 32 fixed screw holes, with a diameter of 3mm
5. The module comes with input/output interfaces and supports cascading multiple modules

Wiring instructions:
1. The left side of the module is the input port, and the right side is the output port.
When controlling a single module, simply 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