LcdDisplay.HD44780.Driver behaviour (lcd_display v0.2.0) View Source

command() ::
  :clear
  | :home
  | {:print, String.t() | byte()}
  | {:set_cursor, integer(), integer()}
  | {:cursor, boolean()}
  | {:blink, boolean()}
  | {:display, boolean()}
  | {:autoscroll, boolean()}
  | {:text_direction, :right_to_left}
  | {:text_direction, :left_to_right}
  | {:scroll, integer()}
  | {:left, integer()}
  | {:right, integer()}
  | {:backlight, boolean()}
  | {:red, boolean()}
  | {:green, boolean()}
  | {:blue, boolean()}

Type that represents a supported display command. Some driver modules do not support the backlight LED commands.

Supported Command	Description
`:clear`	Clear the display.
`:home`	Move the cursor home.
`:print`	Print a character or text at the current cursor.
`:set_cursor`	Set the cursor position (row and column).
`:cursor`	Switch on/off the underline cursor.
`:display`	Switch on/off the display without losing what is on it.
`:blink`	Switch on/off the block cursor.
`:autoscroll`	Make existing text shift when new text is printed.
`:text_direction`	Make text flow left/right from the cursor.
`:scroll`	Scroll text left and right.
`:left`	Move the cursor left.
`:right`	Move the cursor right.
`:backlight`	Switch on/off the backlight.
`:red`	Switch on/off the red LED.
`:green`	Switch on/off the green LED.
`:blue`	Switch on/off the blue LED.

config()

Specs

config() :: map()

feature()

Specs

feature() :: :entry_mode | :display_control

Type that represents an available display feature.

num_cols()

Specs

num_cols() :: 8..20

num_rows()

Specs

num_rows() :: 1..4

t()

Specs

t() :: %{
  :driver_module => atom(),
  :rows => num_rows(),
  :cols => num_cols(),
  :entry_mode => byte(),
  :display_control => byte(),
  :backlight => boolean(),
  required(atom()) => any()
}

Type that represents the display state.

Link to this section Functions

using(_)

(macro)

Injects the common logic for an LCD driver. For display flags, please refer to HD44780 data sheet.

Examples

use LcdDisplay.HD44780.Driver

Link to this section Callbacks

execute(t, command)

Specs

execute(t(), command()) :: {:ok, t()} | {:error, any()}

Executes the specified command and returns a new display state.

start(config)

Specs

start(config()) :: {:ok, t()} | {:error, any()}

Initializes the LCD driver and returns the initial display state.

write_data(t, byte)

Specs

write_data(t(), byte()) :: t()

Sends a data byte to the display.

write_instruction(t, byte)

Specs

write_instruction(t(), byte()) :: t()

Sends an instruction byte to the display.