Support for the on-board display and buttons on Pimoroni Pirate Audio.
Pimoroni Pirate Audio is a family of small factor expansion boards for Raspberry Pi, especially suitable for Raspberry Pi Zero. While it supports MPD (Music Player Daemon) out of the box, I wanted a solution based on Kodi to offer a better experience to the family. We're already using Kore to access our home theater system and want to control all home players by a single app.
apt-get install python-rpi.gpio python-spidev python-pil fonts-symbola
To see what Kodi is displaying, long press (more than 1 sec) the B button. A portion of current Kodi screen will be shown. To show different part of the screen, press A or X button. The A button cycles between top left and bottom left part, the X button cycles between top right and bottom right. Note that what you see is a screenshot, not a live view. To refresh the screen, press the Y button.
Repeatedly pressing the B button switches among sets of keys. By pressing a button, the corresponding key is sent to Kodi (see the onscreen icons).
Long pressing the B button again returns to the player view.
Note that when Kodi is in a screen saver mode, screenshots may show garbage. Send any key to Kodi to dismiss the screen saver.
The heart of the addon is a piratedisplay Python module. It is a from scratch implemention of ST7789 display driver in Python. While there is an existing ST7789 PIP project, it is unsatisfactory: it initializes the display in a rather weird way (limits the number of colors that can be displayed, instructs the hardware to rotate the image by 90° and compensates for that by rotating by -90° in sofware, sets a custom hard coded gamma, etc). The piratedisplay module is much more performant. With the same image displayed in a loop:
| . | ST7789 PIP | piratedisplay |
|---|---|---|
| FPS | 3.7 | > 19 |
| CPU consumption | ~ 50% | ~ 15% |
| initialization | 2.5 sec | 1.5 sec |
In addition, the piratedisplay module handles the buttons including optional software repeat and user timers.
The module is designed to be usable on its own in other projects.