hd44780

Documentation

Overview

Package hd44780 provides a driver for the HD44780 LCD controller.

Datasheet: https://www.sparkfun.com/datasheets/LCD/HD44780.pdf

Index

• Constants
• type Buser
• type Config
• type Device
  • func NewGPIO4Bit(dataPins []machine.Pin, e, rs, rw machine.Pin) (Device, error)
  • func NewGPIO8Bit(dataPins []machine.Pin, e, rs, rw machine.Pin) (Device, error)
  • func (d *Device) Busy() bool
  • func (d *Device) ClearBuffer()
  • func (d *Device) ClearDisplay()
  • func (d *Device) Configure(cfg Config) error
  • func (d *Device) CreateCharacter(cgramAddr uint8, data []byte)
  • func (d *Device) Display() error
  • func (d *Device) SendCommand(command byte)
  • func (d *Device) SetCursor(x, y uint8)
  • func (d *Device) Size() (w, h int16)
  • func (d *Device) Write(data []byte) (n int, err error)
• type GPIO
  • func (g *GPIO) Read(data []byte) (n int, err error)
  • func (g *GPIO) SetCommandMode(set bool)
  • func (g *GPIO) Write(data []byte) (n int, err error)
  • func (g *GPIO) WriteOnly() bool

Constants

const (
	// These are the default execution times for the Clear and
	// Home commands and everything else.
	//
	// These are used if RW is passed as machine.NoPin and ignored
	// otherwise.
	//
	// They are set conservatively here and can be tweaked in the
	// Config structure.
	DefaultClearHomeTime = 80 * time.Millisecond
	DefaultInstrExecTime = 80 * time.Microsecond
)

const (
	DISPLAY_CLEAR = 0x1
	CURSOR_HOME   = 0x2

	ENTRY_MODE       = 0x4
	CURSOR_DECREASE  = ENTRY_MODE | 0x0
	CURSOR_INCREASE  = ENTRY_MODE | 0x2
	DISPLAY_SHIFT    = ENTRY_MODE | 0x1
	DISPLAY_NO_SHIFT = ENTRY_MODE | 0x0

	DISPLAY_ON_OFF   = 0x8
	DISPLAY_ON       = DISPLAY_ON_OFF | 0x4
	DISPLAY_OFF      = DISPLAY_ON_OFF | 0x0
	CURSOR_ON        = DISPLAY_ON_OFF | 0x2
	CURSOR_OFF       = DISPLAY_ON_OFF | 0x0
	CURSOR_BLINK_ON  = DISPLAY_ON_OFF | 0x1
	CURSOR_BLINK_OFF = DISPLAY_ON_OFF | 0x0

	CURSOR_DISPLAY_SHIFT = 0x10
	CURSOR_SHIFT_RIGHT   = CURSOR_DISPLAY_SHIFT | 0x4
	CURSOR_SHIFT_LEFT    = CURSOR_DISPLAY_SHIFT | 0x0
	DISPLAY_SHIFT_RIGHT  = CURSOR_DISPLAY_SHIFT | 0xC
	DISPLAY_SHIFT_LEFT   = CURSOR_DISPLAY_SHIFT | 0x8

	FUNCTION_MODE    = 0x20
	DATA_LENGTH_8BIT = FUNCTION_MODE | 0x10
	DATA_LENGTH_4BIT = FUNCTION_MODE | 0x0
	TWO_LINE         = FUNCTION_MODE | 0x8
	ONE_LINE         = FUNCTION_MODE | 0x0
	FONT_5X10        = FUNCTION_MODE | 0x4
	FONT_5X8         = FUNCTION_MODE | 0x0

	BUSY      = 0x80
	CGRAM_SET = 0x40
	DDRAM_SET = 0x80
)

Types

type Buser

type Buser interface {
	io.ReadWriter
	SetCommandMode(set bool)
	WriteOnly() bool
}

type Config

type Config struct {
	Width         int16
	Height        int16
	CursorBlink   bool
	CursorOnOff   bool
	Font          uint8
	ClearHomeTime time.Duration // time clear/home instructions might take - use 0 for the default
	InstrExecTime time.Duration // time all other instructions might take - use 0 for the default
}

type Device

type Device struct {
	// contains filtered or unexported fields
}

func NewGPIO4Bit

func NewGPIO4Bit(dataPins []machine.Pin, e, rs, rw machine.Pin) (Device, error)

NewGPIO4Bit returns 4bit data length HD44780 driver. Datapins are LCD DB pins starting from DB4 to DB7

If your device has RW set permanently to ground then pass in rw as machine.NoPin

func NewGPIO8Bit

func NewGPIO8Bit(dataPins []machine.Pin, e, rs, rw machine.Pin) (Device, error)

NewGPIO8Bit returns 8bit data length HD44780 driver. Datapins are LCD DB pins starting from DB0 to DB7

If your device has RW set permanently to ground then pass in rw as machine.NoPin

func (*Device) Busy

func (d *Device) Busy() bool

Busy returns true when hd447890 is busy

func (*Device) ClearBuffer

func (d *Device) ClearBuffer()

ClearBuffer clears internal buffer

func (*Device) ClearDisplay

func (d *Device) ClearDisplay()

ClearDisplay clears displayed content and buffer

func (*Device) Configure

func (d *Device) Configure(cfg Config) error

Configure initializes device

func (*Device) CreateCharacter

func (d *Device) CreateCharacter(cgramAddr uint8, data []byte)

CreateCharacter crates characters using data and stores it under cgram Addr in CGRAM

func (*Device) Display

func (d *Device) Display() error

Display sends the whole buffer to the screen at cursor position

func (*Device) SendCommand

func (d *Device) SendCommand(command byte)

SendCommand sends commands to driver

func (*Device) SetCursor

func (d *Device) SetCursor(x, y uint8)

SetCursor moves cursor to position x,y, where (0,0) is top left corner and (width-1, height-1) bottom right

func (*Device) Size

func (d *Device) Size() (w, h int16)

Size returns the current size of the display.

func (*Device) Write

func (d *Device) Write(data []byte) (n int, err error)

Write writes data to internal buffer

type GPIO

type GPIO struct {
	// contains filtered or unexported fields
}

func (*GPIO) Read

func (g *GPIO) Read(data []byte) (n int, err error)

Read reads len(data) bytes from display RAM to data starting from RAM address counter position Ram address can be changed by writing address in command mode

func (*GPIO) SetCommandMode

func (g *GPIO) SetCommandMode(set bool)

SetCommandMode sets command/instruction mode

func (*GPIO) Write

func (g *GPIO) Write(data []byte) (n int, err error)

Write writes len(data) bytes from data to display driver

func (*GPIO) WriteOnly

func (g *GPIO) WriteOnly() bool

WriteOnly is true if you passed rw in as machine.NoPin