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lcd.c
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lcd.c
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/****************************************************************************
Title : HD44780U LCD library
Author: Peter Fleury <[email protected]> http://jump.to/fleury
File: $Id: lcd.c,v 1.14.2.1 2006/01/29 12:16:41 peter Exp $
Software: AVR-GCC 3.3
Target: any AVR device, memory mapped mode only for AT90S4414/8515/Mega
DESCRIPTION
Basic routines for interfacing a HD44780U-based text lcd display
Originally based on Volker Oth's lcd library,
changed lcd_init(), added additional constants for lcd_command(),
added 4-bit I/O mode, improved and optimized code.
Library can be operated in memory mapped mode (LCD_IO_MODE=0) or in
4-bit IO port mode (LCD_IO_MODE=1). 8-bit IO port mode not supported.
Memory mapped mode compatible with Kanda STK200, but supports also
generation of R/W signal through A8 address line.
USAGE
See the C include lcd.h file for a description of each function
*****************************************************************************/
#include <inttypes.h>
#include <avr/io.h>
#include <avr/pgmspace.h>
#include "lcd.h"
//////////////////////////////////////// Present in Peter Fleury code, modified as per the requirements //////////////////////////////////
//
/*
** constants/macros
*/
// #define DDR(x) (*(&x - 1)) /* address of data direction register of port x */
// #if defined(__AVR_ATmega64__) || defined(__AVR_ATmega128__)
// /* on ATmega64/128 PINF is on port 0x00 and not 0x60 */
// #define PIN(x) ( &PORTF==&(x) ? _SFR_IO8(0x00) : (*(&x - 2)) )
// #else
// #define PIN(x) (*(&x - 2)) /* address of input register of port x */
// #endif
//
//#if LCD_IO_MODE
//////////////////////////////////////// Present in Peter Fleury code, modified as per the requirements //////////////////////////////////
/*
** constants/macros
*/
#define lcd_e_delay() __asm__ __volatile__( " rjmp 1f \n 1: " );
#define lcd_e_high() LCD_E_PORT |= _BV(LCD_E_PIN);
#define lcd_e_low() LCD_E_PORT &= ~_BV(LCD_E_PIN);
#define lcd_e_toggle() toggle_e()
#define lcd_rs_high() LCD_RS_PORT |= _BV(LCD_RS_PIN)
#define lcd_rs_low() LCD_RS_PORT &= ~_BV(LCD_RS_PIN)
//////////////////////////////////////// Present in Peter Fleury code, modified as per the requirements //////////////////////////////////
//
//#define lcd_rw_high() LCD_RW_PORT |= _BV(LCD_RW_PIN)
//#define lcd_rw_low() LCD_RW_PORT &= ~_BV(LCD_RW_PIN)
//
// #define lcd_rs_high() LCD_RS_PORT |= _BV(LCD_RS_PIN)
// #define lcd_rs_low() LCD_RS_PORT &= ~_BV(LCD_RS_PIN)
// #endif
// #if LCD_IO_MODE
// #if LCD_LINES==1
// #define LCD_FUNCTION_DEFAULT LCD_FUNCTION_4BIT_1LINE
// #else
// #define LCD_FUNCTION_DEFAULT LCD_FUNCTION_4BIT_2LINES
// #endif
// #else
// #if LCD_LINES==1
// #define LCD_FUNCTION_DEFAULT LCD_FUNCTION_8BIT_1LINE
// #else
// #define LCD_FUNCTION_DEFAULT LCD_FUNCTION_8BIT_2LINES
// #endif
// #endif
// #if LCD_CONTROLLER_KS0073
// #if LCD_LINES==4
// #define KS0073_EXTENDED_FUNCTION_REGISTER_ON 0x24 /* |0|010|0100 4-bit mode extension-bit RE = 1 */
// #define KS0073_EXTENDED_FUNCTION_REGISTER_OFF 0x20 /* |0|000|1001 4 lines mode */
// #define KS0073_4LINES_MODE 0x09 /* |0|001|0000 4-bit mode, extension-bit RE = 0 */
// #endif
// #endif
//////////////////////////////////////// Present in Peter Fleury code, modified as per the requirements //////////////////////////////////
/* function prototypes */
static void toggle_e( void );
/**
@brief Delay function
@param delay cycles
@return none
*/
/*
** local functions
*/
/*************************************************************************
delay loop for small accurate delays: 16-bit counter, 4 cycles/loop
*************************************************************************/
static inline void _delayFourCycles(unsigned int __count)
{
if ( __count == 0 )
__asm__ __volatile__( "rjmp 1f\n 1:" ); // 2 cycles
else
__asm__ __volatile__ (
"1: sbiw %0,1" "\n\t"
"brne 1b" // 4 cycles/loop
: "=w" (__count)
: "0" (__count)
);
}
/*************************************************************************
delay for a minimum of <us> microseconds
the number of loops is calculated at compile-time from MCU clock frequency
*************************************************************************/
#define delay(us) _delayFourCycles( ( ( 1 *(XTAL/ 4000 ) )*us)/ 1000 )
/**
@brief toggle Enable Pin to initiate write
@param none
@return none
*/
static void toggle_e( void )
{
lcd_e_high();
lcd_e_delay();
delay( 1 );
lcd_e_low();
} /* toggle_e */
/**
@brief toggle Enable Pin to initiate write
@param data info to be wirtten
rs write data / write command
@return none
*/
/**
@brief toggle Enable Pin to initiate write
@param data info to be wirtten
rs write data / write command
@return none
*/
// #endif
/*************************************************************************
Low-level function to write byte to LCD controller
Input: data byte to write to LCD
rs 1: write data
0: write instruction
Returns: none
*************************************************************************/
/////////////////////////// We are not using user input as a criteria for setting up the LCD, only output mode is used ///////////////////////////////
// #if LCD_IO_MODE
static void lcd_write(uint8_t data,uint8_t rs)
{
unsigned char dataBits ;
if (rs) { /* write data (RS=1) */
lcd_rs_high();
}
else { /* write instruction (RS=0) */
lcd_rs_low();
}
/* output high nibble first */
dataBits = LCD_DATA0_PORT & 0x0F;
LCD_DATA0_PORT = dataBits |(data & 0xF0 );
lcd_e_toggle();
delay(5000);
/* output low nibble */
LCD_DATA0_PORT = dataBits | ((data << 4 ) & 0xF0 );
lcd_e_toggle();
delay(5000);
/* all data pins high (inactive) */
LCD_DATA0_PORT = dataBits | 0xF0 ;
} /* lcd_write */
/**
@brief Send LCD controller instruction command
@param cmd instruction to send to LCD controller, see HD44780 data sheet
@return none
*/
/*************************************************************************
Send LCD controller instruction command
Input: instruction to send to LCD controller, see HD44780 data sheet
Returns: none
*************************************************************************/
void lcd_command(uint8_t cmd)
{
lcd_write(cmd, 0 );
} /* lcd_command */
static inline void lcd_newline(uint8_t pos)
{
register uint8_t addressCounter;
if ( pos < (LCD_START_LINE2) )
addressCounter = LCD_START_LINE2;
else
addressCounter = LCD_START_LINE1;
lcd_command(( 1 <<LCD_DDRAM)+addressCounter);
} /* lcd_newline */
/**
@brief Send data byte to LCD controller
Similar to lcd_putc(), but without interpreting LF
@param data byte to send to LCD controller, see HD44780 data sheet
@return none
*/
/*************************************************************************
Send data byte to LCD controller
Input: data to send to LCD controller, see HD44780 data sheet
Returns: none
*************************************************************************/
void lcd_data(uint8_t data)
{
lcd_write(data, 1 );
} /* lcd_data */
/**
@brief Set cursor to specified position
@param x horizontal position\n (0: left most position)
@param y vertical position\n (0: first line)
@return none
*/
/*************************************************************************
Set cursor to specified position
Input: x horizontal position (0: left most position)
y vertical position (0: first line)
Returns: none
*************************************************************************/
void lcd_gotoxy(uint8_t x, uint8_t y)
{
if ( y== 0 )
lcd_command(( 1 <<LCD_DDRAM)+LCD_START_LINE1+x);
else
lcd_command(( 1 <<LCD_DDRAM)+LCD_START_LINE2+x);
} /* lcd_gotoxy */
/**
@brief Clear display and set cursor to home position
@param void
@return none
*/
/*************************************************************************
Clear display and set cursor to home position
*************************************************************************/
void lcd_clrscr( void )
{
lcd_command( 1 <<LCD_CLR);
} /* lcd_clrscr */
/**
@brief Set cursor to home position
@param void
@return none
*/
/*************************************************************************
Set cursor to home position
*************************************************************************/
void lcd_home( void )
{
lcd_command( 1 <<LCD_HOME);
} /* lcd_home */
/**
@brief Display character at current cursor position
@param c character to be displayed
@return none
*/
void lcd_putc( char c)
{
lcd_write(c, 1 );
} /* lcd_putc */
/**
@brief Display string without auto linefeed
@param s string to be displayed
@return none
*/
void lcd_puts( const char *s)
{
register char c;
while ( (c = *s++) )
{
lcd_putc(c);
}
} /* lcd_puts */
/**
@brief Display string from program memory without auto linefeed
@param s string from program memory be be displayed
@return none
@see lcd_puts_P
*/
void lcd_puts_p( const char *progmem_s)
{
register char c;
while ( (c = pgm_read_byte(progmem_s++)) )
{
lcd_putc(c);
}
} /* lcd_puts_p */
/**
@brief Initialize display and select type of cursor
@param dispAttr \b LCD_DISP_OFF display off\n
\b LCD_DISP_ON display on, cursor off\n
\b LCD_DISP_ON_CURSOR display on, cursor on\n
\b LCD_DISP_ON_CURSOR_BLINK display on, cursor on flashing
@return none
*/
void lcd_init(uint8_t dispAttr)
{
/////////////////////////// We are not using user input as a criteria for setting up the LCD, only output mode is used ///////////////////////////////
// #if LCD_IO_MODE
/*
* Initialize LCD to 4 bit I/O mode
*/
// if ( ( &LCD_DATA0_PORT == &LCD_DATA1_PORT) && ( &LCD_DATA1_PORT == &LCD_DATA2_PORT ) && ( &LCD_DATA2_PORT == &LCD_DATA3_PORT )
// && ( &LCD_RS_PORT == &LCD_DATA0_PORT) && ( &LCD_RW_PORT == &LCD_DATA0_PORT) && (&LCD_E_PORT == &LCD_DATA0_PORT)
// && (LCD_DATA0_PIN == 0 ) && (LCD_DATA1_PIN == 1) && (LCD_DATA2_PIN == 2) && (LCD_DATA3_PIN == 3)
// && (LCD_RS_PIN == 4 ) && (LCD_RW_PIN == 5) && (LCD_E_PIN == 6 ) )
// {
// /* configure all port bits as output (all LCD lines on same port) */
// DDR(LCD_DATA0_PORT) |= 0x7F;
// }
// else if ( ( &LCD_DATA0_PORT == &LCD_DATA1_PORT) && ( &LCD_DATA1_PORT == &LCD_DATA2_PORT ) && ( &LCD_DATA2_PORT == &LCD_DATA3_PORT )
// && (LCD_DATA0_PIN == 0 ) && (LCD_DATA1_PIN == 1) && (LCD_DATA2_PIN == 2) && (LCD_DATA3_PIN == 3) )
// {
/* configure all port bits as output (all LCD data lines on same port, but control lines on different ports) */
// DDR(LCD_DATA0_PORT) |= 0x0F;
// DDR(LCD_RS_PORT) |= _BV(LCD_RS_PIN);
// DDR(LCD_RW_PORT) |= _BV(LCD_RW_PIN);
// DDR(LCD_E_PORT) |= _BV(LCD_E_PIN);
// }
// else
// {
/* configure all port bits as output (LCD data and control lines on different ports */
// DDR(LCD_RS_PORT) |= _BV(LCD_RS_PIN);
// DDR(LCD_RW_PORT) |= _BV(LCD_RW_PIN);
// DDR(LCD_E_PORT) |= _BV(LCD_E_PIN);
// DDR(LCD_DATA0_PORT) |= _BV(LCD_DATA0_PIN);
// DDR(LCD_DATA1_PORT) |= _BV(LCD_DATA1_PIN);
// DDR(LCD_DATA2_PORT) |= _BV(LCD_DATA2_PIN);
// DDR(LCD_DATA3_PORT) |= _BV(LCD_DATA3_PIN);
// }
/////////////////////////// We are not using user input as a criteria for setting up the LCD, only output mode is used ///////////////////////////////
/* wait 16ms or more after power-on */
delay( 16000 );
/* initial write to lcd is 8bit */
lcd_rs_low();
LCD_DATA3_PORT &= ~_BV(LCD_DATA3_PIN);
LCD_DATA2_PORT &= ~_BV(LCD_DATA2_PIN);
LCD_DATA1_PORT |= _BV(LCD_DATA1_PIN); // _BV(LCD_FUNCTION)>>4;
LCD_DATA0_PORT |= _BV(LCD_DATA0_PIN); // _BV(LCD_FUNCTION_8BIT)>>4;
/* repeat last command */
lcd_e_toggle();
delay( 5000 ); /* delay, busy flag can't be checked here */
/* repeat last command */
lcd_e_toggle();
delay( 200); /* delay, busy flag can't be checked here */
/* repeat last command a third time */
lcd_e_toggle();
delay( 200); /* delay, busy flag can't be checked here */
/////////////////////////// We are not using LCD in 8 bit mode, only 4 bit mode is used ////////////////////////////////////////
// #else
/*
* Initialize LCD to 8 bit memory mapped mode
*/
/* enable external SRAM (memory mapped lcd) and one wait state */
// MCUCR = _BV(SRE) | _BV(SRW);
/* reset LCD */
// delay(16000); /* wait 16ms after power-on */
// lcd_write(LCD_FUNCTION_8BIT_1LINE,0); /* function set: 8bit interface */
// delay(4992); /* wait 5ms */
// lcd_write(LCD_FUNCTION_8BIT_1LINE,0); /* function set: 8bit interface */
// delay(64); /* wait 64us */
// lcd_write(LCD_FUNCTION_8BIT_1LINE,0); /* function set: 8bit interface */
// delay(64); /* wait 64us */
// #endif
/////////////////////////// We are not using LCD in 8 bit mode, only 4 bit mode is used ////////////////////////////////////////
// #if KS0073_4LINES_MODE
/* Display with KS0073 controller requires special commands for enabling 4 line mode */
// lcd_command(KS0073_EXTENDED_FUNCTION_REGISTER_ON);
// lcd_command(KS0073_4LINES_MODE);
// lcd_command(KS0073_EXTENDED_FUNCTION_REGISTER_OFF);
// #else
// lcd_command(LCD_FUNCTION_DEFAULT); /* function set: display lines */
// #endif
/////////////////////////// We are not using LCD in 8 bit mode, only 4 bit mode is used ////////////////////////////////////////
/* now configure for 4bit mode */
LCD_DATA0_PORT &= ~_BV(LCD_DATA0_PIN); // LCD_FUNCTION_4BIT_1LINE>>4
lcd_e_toggle();
delay( 5000 ); /* some displays need this additional delay */
/* from now the LCD only accepts 4 bit I/O, we can use lcd_command() */
lcd_command(LCD_FUNCTION_4BIT_2LINES); /* function set: display lines */
delay( 64 ); /* wait 64us */
lcd_command(LCD_DISP_OFF); /* display on, cursor on */
delay( 64 ); /* wait 64us */
lcd_clrscr(); /* display clear */
delay( 64 ); /* wait 64us */
lcd_command(LCD_MODE_DEFAULT); /* set entry mode */
delay( 200 ); /* wait 200us */
lcd_command(dispAttr); /* display/cursor control */
} /* lcd_init */