PCA9622Matrix8x8

Elixir/Nerves driver for the switch-science "I2C 8x8 LEDマトリックス基板" (I2C 8x8 LED matrix board) board, which drives an 8x8 LED matrix over I2C using the PCA9622 constant-current LED driver in a row/column multiplexed configuration.

Includes PCA9622Matrix8x8.CharGen, a small character generator that renders decimal digits (0-9) and, given a radix of 16, hexadecimal digits (A-F) as 8x8 bitmaps suitable for PCA9622Matrix8x8.set_matrix/1.

Installation

The package can be installed by adding pca9622matrix8x8 to your list of dependencies in mix.exs:

def deps do
  [
    {:pca9622matrix8x8, "~> 0.1.0"}
  ]
end

Not yet published to hex.pm; until then, depend on it via path: or git:.

Usage

# Start the matrix driver (a GenServer) under your supervision tree.
PCA9622Matrix8x8.start_link()

# Show a hexadecimal digit (e.g. "F").
PCA9622Matrix8x8.CharGen.digit_strlist(15, 16)
|> PCA9622Matrix8x8.CharGen.strlist_tuples()
|> PCA9622Matrix8x8.set_matrix()

start_link/1 takes an options keyword list, so multiple boards can be driven independently:

PCA9622Matrix8x8.start_link(
  bus_name: "i2c-1",
  i2c_address: 0x52,
  name: :second_matrix
)

PCA9622Matrix8x8.set_matrix(:second_matrix, mat)

Pass name: nil to start an unnamed process and address it by pid instead.

See PCA9622Matrix8x8.Demo for a complete example that counts up once a second and displays the current number.

Documentation can be generated with ExDoc and published on HexDocs. Once published, the docs can be found at https://hexdocs.pm/pca9622matrix8x8.