The MAX7219 is an integrated serial input / output common-cathode display driver,
it is connected to a microprocessor with 8digit 7segment digital LED display
can also be connected to the bar graph display or 64 separate LED.
On B BCD encoder including an on chip,multi channel scanning loop word drive,
but also an 8 x 8 static RAM is used to store each data.
Only one external register is used to set the current of each LED segment.
A convenient four wire serial interface can connect all general purpose microprocessor.
Each data can be addressed in the update does not need to rewrite all the display.
MAX7219 also allows the user to select on each data coding or non-coding.
The entire device contains a 150uA low-power shutdown mode,
analog and digital brightness control,
a scan-limit register allows the user to display the 1-8 bits of data,
as well as a let all LED light detection mode.
Only need three IO ports can drive a dot-matrix! Dot-matrix display,flicker-free! Supports cascading...

Description:

 1.A single module can drive an 8 * 8 common cathode lattice
2.Module Operating voltage: 5V.
3.Module size: 5 cm long X 3.2 cm wide X 1.5 cm high
4.With four screws hole, aperture 3mm, by using our M3 Tongzhu fixed
5.Module with input and output interfaces, supports multiple modules cascade

Wiring instructions:

1.The module left as an input port to the output port on the right.
2.The control of a single module, simply input port to the CPU
3.Multiple modules cascade input termination CPU, 2 output termination module,
a module of the input of the input terminal, the output terminal of the first two modules of the first three modules, and so on ...

51 MCU, for example:
VCC → 5V
GND → GND
DIN → P22
CS → P21
CLK → P20