Wiring instructions:

The left side of the module to the input port, the right to an output port
When the control of a single module, simply input port connected to CPU
When a plurality of cascaded modules, input and output termination CPU, an input terminal of the second output end of the first module a module, the first two modules of the input terminal of the three termination modules, and so on...
51 microcontrollers, for example:
VCC 5V
GND GND
DIN P2.2
CS P2.1
CLK P2.0
Size for manual measurement, there may be a 0 to 2 cm error, belongs to the normal phenomenon.
And due to the difference between different monitors, the picture may not reflect the actual color of the item.

Package list:
1x MAX7219 Dot Matrix Module 4-in-1
1x 20cm DuPont line 5pin