LcdDisplay.HD44780.SN74HC595 (lcd_display v0.4.0)

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Knows how to commuticate with HD44780 type display through the 8-bit shift register SN74HC595. You can turn on/off the backlight.

Usage

iex> Circuits.SPI.bus_names()
["spidev0.0", "spidev0.1"]
config = %{
  spi_bus: "spidev0.0",      # SPI bus name
  rows: 2,                   # the number of display rows
  cols: 16,                  # the number of display columns
  font_size: "5x8"           # "5x10" or "5x8"
}

# Start the LCD driver and get the initial display state.
{:ok, display} = LcdDisplay.HD44780.SN74HC595.start(config)

# Run a command and the display state will be updated.
{:ok, display} = LcdDisplay.HD44780.SN74HC595.execute(display, {:print, "Hello world"})

Pin assignment

This module assumes the following pin assignment:

SN74HC595HD44780
QA-
QBRS (Register Select)
QCE (Enable)
QDDB7 (Data Bus 7)
QEDB6 (Data Bus 6)
QFDB5 (Data Bus 5)
QGDB4 (Data Bus 4)
QHLED

Summary

Types

config()

The configuration options.

display_driver()

Functions

execute(display, command)

Executes the specified command and returns a new display state.

start(config)

Initializes the LCD driver and returns the initial display state.

Types

config()

@type config() :: %{
  optional(:rows) => String.t(),
  optional(:cols) => pos_integer(),
  optional(:font_size) => pos_integer()
}

The configuration options.

display_driver()

@type display_driver() :: LcdDisplay.HD44780.Driver.t()

Functions

execute(display, command)

Executes the specified command and returns a new display state.

start(config)

@spec start(config()) :: {:ok, display_driver()} | {:error, any()}

Initializes the LCD driver and returns the initial display state.