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 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.
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.
As the main function of the Parola library is to enable text animations, it is important to understand how these are set up and managed to completion from user code.
From a user perspective, Parola animation consist of 3 parts – setting up, running and resetting the animation. The process is not complex and is illustrated in the numerous library examples. This article breaks these down and explains how the Parola class methods apply in each phase.
The key function of the Parola library is to display text using different animations. These animations are built around a core supporting framework and largely follow the same patterns. This article explores how Parola animations code is constructed so that advanced users of the library have enough information to be able to write (and contribute!) their own new animations.
Managing fonts in the is a key factor in the Parola/MD_MAX72xx libraries to being able to support multiple languages and diverse alphabets.
In the first part we looked at how fonts are defined and the tools used to create the bitmaps for each character. In this part we will look at the Parola and MD_MAX72xx library methods that access and manage font data in the library code.
The Parola library allows you to display text on MAX72xx controlled LED matrices using a wide range of text effects. One of the base components for this flexibility are the replaceable fonts and the utilities that allow new fonts to be designed and implemented in the library code.