lcd.h File Reference

LCD control, formatting, printout. More...

#include <inttypes.h>
#include <stdio.h>
#include <avr/pgmspace.h>


Functions
void	lcd_init (void)
void	lcd_set_custom_char (uint8_t chnum, uint8_t *data)
void	lcd_write_data (uint8_t data)
void	lcd_print (const char *string)
int	lcd_vprintf (const char *fmt, va_list ap)
int	lcd_printf (const char *fmt,...)
int	lcd_print_char (char ch, FILE *f)
void	lcd_clear (void)
uint8_t	lcd_get_pos (void)
void	lcd_set_pos (uint8_t p)

Detailed Description

The happyboard LCD is a 2x16 character device. The OS code treats the LCD as a single 1x32 line display. This means that printf("012345690123456789") will display:

         +----------------+
 line 1: |0123456789012345|
 line 2: |6789            |
         +----------------+

For general LCD printing, printf() is suggested. printf() is a wrapper around the functions documented below. As such these functions should only be used when printf() is insufficient.

Printing a newline character ("\n" in C) to the display clears it. Thus, printf("hello world\n"), will not display anything (the display is cleared after the text is displayed). Instead, you should use printf("\nhello world")

this will clear the display and then display the text.

The OS will occasionally use the bottom right character of the display for warning/information icons, which may obscure user printouts (if they use the full 32 characters of the display).

The LCD supports 8 user-defined characters. On startup these characters are set to a system defaults as follows:

 0: unsused
 1: smiley face
 2: alternate smiley face
 3: frowny face
 4: low battery indicator
 5: loading indicator
 6: bootloader indicator
 7: unused

These special characters can be reconfigured by the user with the lcd_set_custom_char() function, as long as you remember this will change the OS warning indicator icons.

Function Documentation

void lcd_clear ( void )

Clear the LCD Screen.

uint8_t lcd_get_pos ( void )

Return the current cursor position.

void lcd_init ( void )

Initialise the LCD driver

void lcd_print ( const char * string )

Display a string to the LCD.

Parameters:

string

string to display

int lcd_print_char	(	char	ch,
		FILE *	f
	)

Print a single character to the LCD.

Parameters:

	ch	character to display
	f	ignored

int lcd_printf	(	const char *	fmt,
			...
	)

Display a formated string to the LCD.

Parameters:

fmt

format to display

void lcd_set_custom_char	(	uint8_t	chnum,
		uint8_t *	data
	)

Sets a custom LCD character. The LCD has space for 8 custom characters (characters 0-7.) Note that the OS uses some of these charaters for the status indicator. The data is read from program (flash) memory and therefore should be defined as PROGMEM, eg:

 uint8_t my_custom_char[] PROGMEM = { 12, 23, 34, 45, 56, 67, 78, 89 };

Parameters:

	chnum	character to set
	data	8 byte array of pixel data

void lcd_set_pos ( uint8_t p )

Set the current cursor position.

Parameters:

position to move to [0..31]

int lcd_vprintf	(	const char *	fmt,
		va_list	ap
	)

Display a formated string to the LCD.

Parameters:

	fmt	format to display
	ap	virtual argument list

void lcd_write_data ( uint8_t data )

Write a data byte to the LCD. Should not normally be needed by user code.

Parameters:

data

byte to write.

lcd.h File Reference

Functions

Detailed Description

Function Documentation