Arduino++
Of all the many questions that have been asked about issues they face when using the MD_Parola and MD_MAX72xx libraries, there are a few themes that keep re-emerging. In this article I’ll cover the top eight questions, their most likely cause and solution.
A question that I am asked on a regular basis is why particular characters in messages are not displayed ‘as-expected’ by the Parola library. These characters, often typed in from the Serial monitor or embedded within strings, contain non-ASCII characters. Here’s what is happening.
A question that often arises is how to ‘save program memory’ when the MD_Parola and MD_MAX72xx libraries are used in an application. In this article we’ll cover how you can do this using the facilities already built into the library code.
A recent feature of the Parola library is sprite based text effects. This extends the functionality of the library to include fully customisable, user defined, animated bitmaps to wipe text on and off the LED matrix display.
Here’s how it works.
The key function of the Parola library is to display text using different animations. From version 2.7 onwards, Parola allows user code to manage mixing graphics with the text. The extensions to the library and what they do is the subject of this article.
The amount of RAM an application uses is printed out by the IDE at compile time. For applications that don’t allocate memory, this is a really good guide to how much spare RAM is available at run time.
However, if an application, like any using the Parola libraries, uses memory from the heap, you need to make sure that there is sufficient memory left for run-time memory allocation.
Vertical LED dot displays are not a common requirement, but they can be created using the standard library with a few tweaks to the software.
As I get questions about vertical displays from time to time, I will cover the basic process of how this is done in this short article.
A very powerful feature of the Parola library is the ability to separate a display into a number of zones. This allows the implementation of sophisticated animations schemes and is a key part of being able to create double height displays.
This post explains what they are, how they are set up, and how to manage them.
An ongoing question on many Arduino forums is how to modify software to suit the different types of matrix modules available. Usually the poster has tried some LED matrix software and the display is reversed or upside down, or animations are disjointed across the module boundaries.
There are clear reasons this happens, and the Parola library has software configuration parameters that allow you to adapt how the software operates to suit your hardware module.
Using the Parola library for double height displays is becoming increasingly popular with library users. Setting up the hardware and the library is not difficult, but it can cause problems if not done correctly. This article will explain the hardware and software setup considerations for trouble-free double height displays.
