Playing audio files with the PCM library
Another way to play sounds is by reading already digitalized sounds.
Audio samples define digital content, often stored as files on filesystems that can be read and converted into audible sound.
Samples can be very heavy from the memory size point of view.
We are going to use the PCM library set up by David A. Mellis from MIT. Like other collaborators, he is happy to be a part of this book.
The reference page is http://hlt.media.mit.edu/?p=1963.
Download the library and install it.
Imagine that we have enough space in the Arduino memory spaces. How can we do the installation if we want to convert a sample on our disks as a C-compatible structure?
The PCM library
Check this code. It is also available in the Chapter09/PCMreader/ folder.
Our PCM reader
There is an array of unsigned char datatypes declared as const, and especially with the PROGMEM keyword named sample.
PROGMEM forces this constant to be put in the program space instead of RAM, because the latter...
