1. Device drivers for VS1053b
The VS1053b is an audio player capable of handling MP3 files. Development was done with this Adafruit breakout. This includes an SD card adaptor which may be used to store MP3 files. MP3 bit rates up to 256Kbps and VBR (variable bit rate) files are supported.
It should be noted that these drivers run the adaptor board's SD card at a higher clock rate than the official SD card driver. If this slot is used, good quality SD cards should be used.
The interface uses seven I/O pins. However the Adafruit card provides 8 GPIO pins which are supported by the driver. You gain a pin :).
There are two versions of the driver: synchronous and asynchronous. The
asynchronous version uses uasyncio to enable tasks (such as a GUI interface)
to run concurrently while playing audio files. Sadly the overhead of uasyncio
prevents audio playback on ESP8266 and ESP32.
Asynchronous driver docs
The synchronous driver has been tested on ESP8266 and ESP32. On Pyboards CD quality audio may be achieved using FLAC files.
Synchronous driver docs
Compatibility matrix:
| Platform | Synchronous | Asynchronous |
|---|---|---|
| Pyboard | FLAC | |
| (1.x and D) | VBR MP3 | VBR MP3 |
| MP3 <= 256Kbps | MP3 <= 256Kbps | |
| Pyboard Lite | Not yet tested | MP3 <= 128Kbps |
| ESP32 | MP3 <= 256Kbps | Unsupported |
| ESP8266 | MP3 <= 256Kbps | Unsupported |
The synchronous driver also supports recording audio to an IMA ADPCM wav file
which can be played by the VS1053b or by other applications.