Moving message display using arduino

Matrix Display Interface with MAX7219

The MAX7219 LED driver saves microcontroller pins and processing time. It uses only three IO pins of an Arduino.  It is easy to connect multiple displays by connecting DIN and DOUT pins.

Using a single MAX7219 you can drive 64 LEDs while you only need 4 wires to interface it to a microcontroller. In addition you can daisy chain multiple MAX7219 chips for bigger displays.

There are 16 output lines from the MAX7219 driving 64 individual LEDs. LEDs are arranged as an 8×8 set of rows and columns. Each colum is pulsed for a short time while the row bits for that column are driven.

MAX7219 SPI Interface

The MAX7219 has a four wire SPI interface – clock, data, chip select and ground – making it very simple to connect to a microcontroller.

  1. Data – DIN – Data Input
  2. Chip select – Load (CSn) – active low Chip select.
  3. Clock – SCK
  4. GND – Ground.
  5. Data out – DOUT – Data Output is used for cascading of multiple MAX7219

Circuit Connections of Matrix Display

In this example we are using two matrix displays to make a Scrolling Display. For cascading of multiple displays connect DOUT of first display to DIN of second display in series. Keep CLK (clock) and Load (CS) pin common (parallel connection).

You can use readily available modules also for making your own scrolling display.

MAX7219 Matix Display

Circuit Connection for using readily Available Display Modules

Note: Here we have used different pins for CS, DATA and LOAD.

MAX7219 mateix led display interface

Arduino Code for MAX7219 interface with Arduino

Download Library from here maxmatrix

The above code displays scrolling text on the display.

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