ST7789-Elixir

ST7789 driver for Elixir.

Tested on my 1.3" SPI Colour Square LCD (240x240) Breakout.

Example

PIN connection

Code

# init ST7789 screen
port = 0                        # spi bus 0
speed_hz = 80 * 1000 * 1000     # 80MHz
dc = 9                          # MISO PIN 9

# first display
cs1 = 0                         # BCM 8 / CE 0
backlight1 = 17                 # BCM 17
disp1 = ST7789.new(port, cs: cs1, backlight: backlight1, dc: dc, speed_hz: speed_hz)

# second display
cs2 = 1                         # BCM 7 / CE 1
backlight2 = 27                 # BCM 27
disp2 = ST7789.new(port, cs: cs2, backlight: backlight2, dc: dc, speed_hz: speed_hz)

# read image from file
{:ok, mat} = OpenCV.imread("/path/to/some/image")
# to binary
{:ok, image_data} = OpenCV.Mat.to_binary(mat)
# display it
ST7789.display(disp1, image_data, :bgr)
# (optional, for demo only) convert to rgb888 colorspace
{:ok, mat} = OpenCV.cvtcolor(mat, OpenCV.cv_color_bgr2rgb)
{:ok, image_data} = OpenCV.Mat.to_binary(mat)
ST7789.display(disp2, image_data, :rgb)

# open video stream
{:ok, cap} = OpenCV.VideoCapture.videocapture(0)
# read a frame
{:ok, mat} = OpenCV.VideoCapture.read(cap)
%{height: h, width: w} = ST7789.size(disp1)
# resize
{:ok, mat} = OpenCV.resize(mat, [h, w])
# to binary
{:ok, image_data} = OpenCV.Mat.to_binary(mat)
# display it
ST7789.display(disp1, image_data, :bgr)
ST7789.display(disp2, image_data, :bgr)

# turn off/on backlight
ST7789.set_backlight(disp1, :off)
ST7789.set_backlight(disp1, :on)
ST7789.set_backlight(disp2, :off)
ST7789.set_backlight(disp2, :on)

Installation

The package can be installed by adding st7789_elixir to your list of dependencies in mix.exs:

def deps do
  [
    {:st7789_elixir, "~> 0.1.5"}
  ]
end

Documentation can be generated with ExDoc and published on HexDocs. Once published, the docs can be found at https://hexdocs.pm/st7789_elixir.