qmk_firmware/internals/hd44780.md

group hd44780

HD44780 Character LCD Driver

Summary

Members	Descriptions
define HD44780_CMD_CLEAR_DISPLAY
define HD44780_CMD_RETURN_HOME
define HD44780_CMD_ENTRY_MODE
define HD44780_ENTRY_MODE_INC
define HD44780_ENTRY_MODE_SHIFT
define HD44780_CMD_DISPLAY
define HD44780_DISPLAY_ON
define HD44780_DISPLAY_CURSOR
define HD44780_DISPLAY_BLINK
define HD44780_CMD_MOVE
define HD44780_MOVE_DISPLAY
define HD44780_MOVE_RIGHT
define HD44780_CMD_FUNCTION
define HD44780_FUNCTION_8_BIT
define HD44780_FUNCTION_2_LINES
define HD44780_FUNCTION_5X10_DOTS
define HD44780_CMD_SET_CGRAM_ADDRESS
define HD44780_CMD_SET_DDRAM_ADDRESS
define HD44780_BUSY_FLAG
public void hd44780_write(uint8_t data,bool isData)	Write a byte to the display.
public uint8_t hd44780_read(bool isData)	Read a byte from the display.
public bool hd44780_busy(void)	Indicates whether the display is currently processing, and cannot accept instructions.
public void hd44780_command(uint8_t command)	Send a command to the display. Refer to the datasheet for the valid commands.
public void hd44780_data(uint8_t data)	Send a byte of data to the display.
public void hd44780_clear(void)	Clear the display.
public void hd44780_home(void)	Move the cursor to the home position.
public void hd44780_on(bool cursor,bool blink)	Turn the display on, and/or set the cursor position.
public void hd44780_off(void)	Turn the display off.
public void hd44780_set_cgram_address(uint8_t address)	Set the CGRAM address.
public void hd44780_set_ddram_address(uint8_t address)	Set the DDRAM address.
public void hd44780_init(bool cursor,bool blink)	Initialize the display.
public void hd44780_set_cursor(uint8_t col,uint8_t line)	Move the cursor to the specified position on the display.
public void hd44780_define_char(uint8_t index,uint8_t * data)	Define a custom character.
public void hd44780_putc(char c)	Print a character to the display. The newline character will move the cursor to the start of the next line.
public void hd44780_puts(const char * s)	Print a string of characters to the display.
public void hd44780_define_char_P(uint8_t index,const uint8_t * data)	Define a custom character from PROGMEM.
public void hd44780_puts_P(const char * s)	Print a string of characters from PROGMEM to the display.

Members

define HD44780_CMD_CLEAR_DISPLAY

define HD44780_CMD_RETURN_HOME

define HD44780_CMD_ENTRY_MODE

define HD44780_ENTRY_MODE_INC

define HD44780_ENTRY_MODE_SHIFT

define HD44780_CMD_DISPLAY

define HD44780_DISPLAY_ON

define HD44780_DISPLAY_CURSOR

define HD44780_DISPLAY_BLINK

define HD44780_CMD_MOVE

define HD44780_MOVE_DISPLAY

define HD44780_MOVE_RIGHT

define HD44780_CMD_FUNCTION

define HD44780_FUNCTION_8_BIT

define HD44780_FUNCTION_2_LINES

define HD44780_FUNCTION_5X10_DOTS

define HD44780_CMD_SET_CGRAM_ADDRESS

define HD44780_CMD_SET_DDRAM_ADDRESS

define HD44780_BUSY_FLAG

public void hd44780_write(uint8_t data,bool isData)

Write a byte to the display.

Parameters

• data The byte to send to the display.

• isData Whether the byte is an instruction or character data.

public uint8_t hd44780_read(bool isData)

Read a byte from the display.

Parameters

• isData Whether to read the current cursor position, or the character at the cursor.

Returns

If isData is true, the returned byte will be the character at the current DDRAM address. Otherwise, it will be the current DDRAM address and the busy flag.

public bool hd44780_busy(void)

Indicates whether the display is currently processing, and cannot accept instructions.

Returns

true if the display is busy.

public void hd44780_command(uint8_t command)

Send a command to the display. Refer to the datasheet for the valid commands.

This function waits for the display to clear the busy flag before sending the command.

Parameters

• command The command to send.

public void hd44780_data(uint8_t data)

Send a byte of data to the display.

This function waits for the display to clear the busy flag before sending the data.

Parameters

• data The byte of data to send.

public void hd44780_clear(void)

Clear the display.

This function is called on init.

public void hd44780_home(void)

Move the cursor to the home position.

This function is called on init.

public void hd44780_on(bool cursor,bool blink)

Turn the display on, and/or set the cursor position.

This function is called on init.

Parameters

• cursor Whether to show the cursor.

• blink Whether to blink the cursor, if shown.

public void hd44780_off(void)

Turn the display off.

public void hd44780_set_cgram_address(uint8_t address)

Set the CGRAM address.

This function is used when defining custom characters.

Parameters

• address The CGRAM address to move to, from 0x00 to 0x3F.

public void hd44780_set_ddram_address(uint8_t address)

Set the DDRAM address.

This function is used when printing characters to the display, and setting the cursor.

Parameters

• address The DDRAM address to move to, from 0x00 to 0x7F.

public void hd44780_init(bool cursor,bool blink)

Initialize the display.

This function should be called only once, before any of the other functions can be called.

Parameters

• cursor Whether to show the cursor.

• blink Whether to blink the cursor, if shown.

public void hd44780_set_cursor(uint8_t col,uint8_t line)

Move the cursor to the specified position on the display.

Parameters

• col The column number to move to, from 0 to 15 on 16x2 displays.

• line The line number to move to, either 0 or 1 on 16x2 displays.

public void hd44780_define_char(uint8_t index,uint8_t * data)

Define a custom character.

Parameters

• index The index of the custom character to define, from 0 to 7.

• data An array of 8 bytes containing the 5-bit row data of the character, where the first byte is the topmost row, and the least significant bit of each byte is the rightmost column.

public void hd44780_putc(char c)

Print a character to the display. The newline character will move the cursor to the start of the next line.

The exact character shown may depend on the ROM code of your particular display - refer to the datasheet for the full character set.

Parameters

• c The character to print.

public void hd44780_puts(const char * s)

Print a string of characters to the display.

Parameters

• s The string to print.

public void hd44780_define_char_P(uint8_t index,const uint8_t * data)

Define a custom character from PROGMEM.

On ARM devices, this function is simply an alias of hd44780_define_char().

Parameters

• index The index of the custom character to define, from 0 to 7.

• data A PROGMEM array of 8 bytes containing the 5-bit row data of the character, where the first byte is the topmost row, and the least significant bit of each byte is the rightmost column.

public void hd44780_puts_P(const char * s)

Print a string of characters from PROGMEM to the display.

On ARM devices, this function is simply an alias of hd44780_puts().

Parameters

• s The PROGMEM string to print.