Package com.diozero.devices

Class HD44780Lcd.GpioLcdConnection

java.lang.Object

com.diozero.devices.HD44780Lcd.GpioLcdConnection

All Implemented Interfaces:

HD44780Lcd.LcdConnection, AutoCloseable

Enclosing class:

HD44780Lcd

public static class HD44780Lcd.GpioLcdConnection
extends Object
implements HD44780Lcd.LcdConnection

Connect via individual GPIO pins, uses 4-bit mode (data pins D4-D7). Wiring (from left-to-right):

 Vss: GND
 Vdd: 5v
 V0: Contrast adjustment (connect to Vdd for full brightness)
 RS: Register Select - GPIO
 RW: Data read/write (not required, read mode not used - can connect to GND)
 E: Enable - GPIO
 D0-D3: Don't connect (currently only 4-bit mode is supported)
 D4-D7: Data pins - GPIO
 A: Backlight LED Cathode (+) - GPIO (need to check 3v3/5v) or Vdd (always on)
 K: Backlight LED Anode (-) - GND
 

Constructor Summary

Constructors

Constructor	Description
GpioLcdConnection(int d4, int d5, int d6, int d7, int enableGpio, int registerSelectGpio)	Use the default device factory and specify GPIO numbers.
GpioLcdConnection(int d4, int d5, int d6, int d7, int backlightGpio, int enableGpio, int registerSelectGpio)	Use the default device factory and specify GPIO numbers.
GpioLcdConnection(int d4, int d5, int d6, int d7, int backlightGpio, int enableGpio, int dataRwGpio, int registerSelectGpio)	Use the default device factory and specify GPIO numbers.
GpioLcdConnection(DigitalOutputDevice d4, DigitalOutputDevice d5, DigitalOutputDevice d6, DigitalOutputDevice d7, DigitalOutputDevice backlightPin, DigitalOutputDevice enablePin, DigitalOutputDevice dataRwPin, DigitalOutputDevice registerSelectPin)	Use the specified digital output devices.
GpioLcdConnection(GpioDeviceFactoryInterface deviceFactory, int d4, int d5, int d6, int d7, int backlightGpio, int enableGpio, int dataRwGpio, int registerSelectGpio)	Use the specified device factory and specify GPIO numbers.

Method Summary

Modifier and Type	Method	Description
void	close()
int	getBacklightBit()	Identify the bit in the byte payload that refers to the backlight control flag 1=on, 0=off.
int	getDataReadWriteBit()	Identify the bit in the byte payload that refers to the read/write flag.
int	getEnableBit()	Identify the bit in the byte payload that refers to the enable flag to start read/write.
int	getRegisterSelectBit()	Identify the bit in the byte payload that refers to the register select flag.
boolean	isDataInHighNibble()	Control whether the data bits in the first or last 4-bits
void	write(byte values)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

GpioLcdConnection

public GpioLcdConnection(int d4,
                         int d5,
                         int d6,
                         int d7,
                         int enableGpio,
                         int registerSelectGpio)

Use the default device factory and specify GPIO numbers. Assumes the RW pin is pulled low and the backlight pin pulled high.

Parameters:

d4 - GPIO number for d4 pin

d5 - GPIO number for d5 pin

d6 - GPIO number for d6 pin

d7 - GPIO number for d7 pin

enableGpio - enable GPIO number

registerSelectGpio - register select GPIO number

GpioLcdConnection

public GpioLcdConnection(int d4,
                         int d5,
                         int d6,
                         int d7,
                         int backlightGpio,
                         int enableGpio,
                         int registerSelectGpio)

Use the default device factory and specify GPIO numbers. Assumes the RW pin is pulled low.

Parameters:

d4 - GPIO number for d4 pin

d5 - GPIO number for d5 pin

d6 - GPIO number for d6 pin

d7 - GPIO number for d7 pin

backlightGpio - backlight control GPIO number (set to -1 if not connected)

enableGpio - enable GPIO number

registerSelectGpio - register select GPIO number

GpioLcdConnection

public GpioLcdConnection(int d4,
                         int d5,
                         int d6,
                         int d7,
                         int backlightGpio,
                         int enableGpio,
                         int dataRwGpio,
                         int registerSelectGpio)

Use the default device factory and specify GPIO numbers.

Parameters:

d4 - GPIO number for d4 pin

d5 - GPIO number for d5 pin

d6 - GPIO number for d6 pin

d7 - GPIO number for d7 pin

backlightGpio - backlight control GPIO number (set to -1 if not connected)

enableGpio - enable GPIO number

dataRwGpio - data read/write GPIO number (not used - connect to GND, set to -1 if not connected)

registerSelectGpio - register select GPIO number

GpioLcdConnection

public GpioLcdConnection(GpioDeviceFactoryInterface deviceFactory,
                         int d4,
                         int d5,
                         int d6,
                         int d7,
                         int backlightGpio,
                         int enableGpio,
                         int dataRwGpio,
                         int registerSelectGpio)

Use the specified device factory and specify GPIO numbers.

Parameters:

deviceFactory - the device factory to use for provisioning the GPIOs

d4 - GPIO number for d4 pin

d5 - GPIO number for d5 pin

d6 - GPIO number for d6 pin

d7 - GPIO number for d7 pin

backlightGpio - backlight control GPIO number (set to -1 if not connected)

enableGpio - enable GPIO number

dataRwGpio - data read/write GPIO number (not used - connect to GND, set to -1 if not connected)

registerSelectGpio - register select GPIO number

GpioLcdConnection

public GpioLcdConnection(DigitalOutputDevice d4,
                         DigitalOutputDevice d5,
                         DigitalOutputDevice d6,
                         DigitalOutputDevice d7,
                         DigitalOutputDevice backlightPin,
                         DigitalOutputDevice enablePin,
                         DigitalOutputDevice dataRwPin,
                         DigitalOutputDevice registerSelectPin)

Use the specified digital output devices.

Parameters:

d4 - Digital output device for d4 pin

d5 - Digital output device for d5 pin

d6 - Digital output device for d6 pin

d7 - Digital output device for d7 pin

backlightPin - backlight control digital output device (set to null if not connected)

enablePin - enable digital output device

dataRwPin - data read/write digital output device (not used - connect to GND, set to null if not connected)

registerSelectPin - register select digital output device

Method Detail

write

public void write(byte values)

Specified by:

write in interface HD44780Lcd.LcdConnection

isDataInHighNibble

public boolean isDataInHighNibble()

Description copied from interface: HD44780Lcd.LcdConnection

Control whether the data bits in the first or last 4-bits

Specified by:

isDataInHighNibble in interface HD44780Lcd.LcdConnection

Returns:

true if the data bits are in the high nibble (bits 4:7)

getBacklightBit

public int getBacklightBit()

Description copied from interface: HD44780Lcd.LcdConnection

Identify the bit in the byte payload that refers to the backlight control flag 1=on, 0=off.

Specified by:

getBacklightBit in interface HD44780Lcd.LcdConnection

Returns:

the backlight control bit number

getEnableBit

public int getEnableBit()

Description copied from interface: HD44780Lcd.LcdConnection

Identify the bit in the byte payload that refers to the enable flag to start read/write. Falling edge triggered

Specified by:

getEnableBit in interface HD44780Lcd.LcdConnection

Returns:

the enable flag bit number

getDataReadWriteBit

public int getDataReadWriteBit()

Description copied from interface: HD44780Lcd.LcdConnection

Identify the bit in the byte payload that refers to the read/write flag. Not implemented. R/W=0: Write, R/W=1: Read

Specified by:

getDataReadWriteBit in interface HD44780Lcd.LcdConnection

Returns:

the read/write flag bit number

getRegisterSelectBit

public int getRegisterSelectBit()

Description copied from interface: HD44780Lcd.LcdConnection

Identify the bit in the byte payload that refers to the register select flag. RS=0: Command, RS=1: Data

Specified by:

getRegisterSelectBit in interface HD44780Lcd.LcdConnection

Returns:

the register select flag bit number

close

public void close()
           throws RuntimeIOException

Specified by:

close in interface AutoCloseable

Specified by:

close in interface HD44780Lcd.LcdConnection

Throws:

RuntimeIOException