For the purposes of creating a simple advertisement, i.e. for a project in which an LED matrix will be used to display animated text, I used two additional libraries. I chose them because I think it was the simplest solution for working with the MAX7219 IC and animating the text. To begin with, a little about the libraries themselves, and the project will be described in the following text. The libraries in question are MAX72xx and Parola.
Arduino Parola library
The Parola library is implemented to work with the MD_MAX2XX library. It depends on the MD_MAX72xx library for hardware control and will run on all hardware supported by that library.
This software library implements functions to simplify the implementation of text special effects on the Parola display.
- Left, right or center text justification in the display field.
- Text scrolling, text entering and exit effects.
- Control display parameters and animation speed.
- Multiple virtual displays (zones) in each string of LED modules.
- User defined fonts and/or individual characters substitutions.
- Double height and vertical displays.
- Support for mixing text and graphics on the same display.
Arduino MAX72XX library
The MAX7219/MAX7221 are compact, serial input/output display drivers that interface microprocessors to 7-segment numeric LED displays of up to 8 digits, bar-graph displays, or 64 individual LEDs. Included on-chip are a BCD code-B decoder, multiplex scan circuitry, segment and digit drivers, and an 8×8 static RAM that stores each digit.
A 4-wire serial interface (SPI) allows the devices to be cascaded, with communications passed through the first device in the chain to all others. Individual elements may be addressed and updated without rewriting the entire display.
This library implements functions that allow the MAX72xx to be used for LED matrices (64 individual LEDs), allowing the programmer to use the LED matrix as a pixel device, displaying graphics elements much like any other pixel addressable display.
Text taken from the library’s official website.
Links to used libraries
1. MD_Parola.h
2. MD_MAX72xx.h