hdc

Documentation

Overview

Package hdc implements driver for popular Hitachi HD44780 LCD controller.

Index

• type Display
  • func (d *Display) ClearAUX() error
  • func (d *Display) ClearDisplay() error
  • func (d *Display) Init() error
  • func (d *Display) MoveCursor(col, row int) error
  • func (d *Display) ReturnHome() error
  • func (d *Display) SetAUX() error
  • func (d *Display) SetAddrCGRAM(addr int) error
  • func (d *Display) SetAddrDDRAM(addr int) error
  • func (d *Display) SetDisplayMode(f DisplayMode) error
  • func (d *Display) SetEntryMode(f EntryMode) error
  • func (d *Display) SetFunction(f Function) error
  • func (d *Display) Shift(f Shift) error
  • func (d *Display) Write(data []byte) (int, error)
  • func (d *Display) WriteByte(b byte) error
  • func (d *Display) WriteString(s string) (int, error)
• type DisplayMode
• type EntryMode
• type Function
• type Shift

Types

type Display

type Display struct {
	ReadWriter io.ReadWriter
	Cols       byte
	Rows       byte
	DS         byte // Data shift: 4-bit nible uses bit numbers from DS to DS+3.
	E          byte // E line.
	RW         byte // R/W line.
	RS         byte // RS line.
	AUX        byte // AUX line (typically used for control backlight).
	// contains filtered or unexported fields
}

Display allows to send commands and data to HD44780 LCD controller in 4-bit mode.

Every byte is sent as two 4-bit nibbles. One nibble is sent by writing three bytes to provided ReadWriter:

• first: with E bit unset, need >= 40 ns
• second: with E bit set, need >= 230 ns
• thrid: with E bit unset, need >= 10 ns

Full E cycle needs >= 500 ns. Display doesn't control proper nible timings, instead ReadWriter implementation must do it.

Display reads busy flag before executing a command. Read command is written with all data bits set to 1.

func (*Display) ClearAUX

func (d *Display) ClearAUX() error

func (*Display) ClearDisplay

func (d *Display) ClearDisplay() error

func (*Display) Init

func (d *Display) Init() error

Init initializes the display to the following state: - 4-bit mode, - one line display if Rows == 1, two line display otherwise, - 5x8 font, - display off, cursor off, blink off, - increment mode, - display cleared and cursor at home position.

func (*Display) MoveCursor

func (d *Display) MoveCursor(col, row int) error

Flush calls bufio.Writer.Flush if bufio.Writer was used as io.Write

func (*Display) ReturnHome

func (d *Display) ReturnHome() error

func (*Display) SetAUX

func (d *Display) SetAUX() error

func (*Display) SetAddrCGRAM

func (d *Display) SetAddrCGRAM(addr int) error

func (*Display) SetAddrDDRAM

func (d *Display) SetAddrDDRAM(addr int) error

func (*Display) SetDisplayMode

func (d *Display) SetDisplayMode(f DisplayMode) error

func (*Display) SetEntryMode

func (d *Display) SetEntryMode(f EntryMode) error

func (*Display) SetFunction

func (d *Display) SetFunction(f Function) error

func (*Display) Shift

func (d *Display) Shift(f Shift) error

func (*Display) Write

func (d *Display) Write(data []byte) (int, error)

func (*Display) WriteByte

func (d *Display) WriteByte(b byte) error

func (*Display) WriteString

func (d *Display) WriteString(s string) (int, error)

type DisplayMode

type DisplayMode byte

const (
	DisplayOff DisplayMode = 0
	DisplayOn  DisplayMode = 1 << 2
	CursorOff  DisplayMode = 0
	CursorOn   DisplayMode = 1 << 1
	BlinkOff   DisplayMode = 0
	BlinkOn    DisplayMode = 1
)

type EntryMode

type EntryMode byte

const (
	ShiftOff EntryMode = 0
	ShiftOn  EntryMode = 1 << 0
	Decr     EntryMode = 0
	Incr     EntryMode = 1 << 1
)

type Function

type Function byte

const (
	OneLine  Function = 0
	TwoLines Function = 1 << 3
	Font5x8  Function = 0
	Font5x10 Function = 1 << 2
)

type Shift

type Shift byte

const (
	Cursor Shift = 0
	Screen Shift = 1 << 3
	Left   Shift = 0
	Right  Shift = 1 << 2
)