lcd.c

/******************************************************************************

                          eXtreme Electronics xAPI(TM)
                          ----------------------------
xAPI is a Powerful but easy to use C library to program the xBoard(TM)
series of AVR development board. The library has support for commonly use tasks
like:-

*LCD interfacing
*MUXED 7 segment displays.
*Remote Control
*Serial Communication
*DC Motor Controls with Speed Control
*Analog Measurement for Sensor Interface.
*Temperature Measurement.
*I2C Communication.
*EEPROM Interface
*Real Time Clock (RTC Interface)

The APIs are highly documented and easy to use even by a beginner.

For More Info Log On to 
www.eXtremeElectronics.co.in

Copyright 2008-2010 eXtreme Electronics India

                                    LCD Core
                                   ----------
This module is used for interfacing with Standard Alpha Numeric LCD Modules.
For More information please see supplied tutorials and videos.

                                     NOTICE
                                    --------
NO PART OF THIS WORK CAN BE COPIED, DISTRIBUTED OR PUBLISHED WITHOUT A
WRITTEN PERMISSION FROM EXTREME ELECTRONICS INDIA. THE LIBRARY, NOR ANY PART
OF IT CAN BE USED IN COMMERCIAL APPLICATIONS. IT IS INTENDED TO BE USED FOR
HOBBY, LEARNING AND EDUCATIONAL PURPOSE ONLY. IF YOU WANT TO USE THEM IN 
COMMERCIAL APPLICATION PLEASE WRITE TO THE AUTHOR.


WRITTEN BY:
AVINASH GUPTA
me@avinashgupta.com

*******************************************************************************/

#include <avr/io.h>
#include <inttypes.h>
#include <util/delay.h>

#include "lcd.h"

//Custom Charset support
#include "custom_char.h"

#define LCD_DATA_PORT   PORT(LCD_DATA)
#define LCD_E_PORT      PORT(LCD_E)
#define LCD_RS_PORT     PORT(LCD_RS)
#define LCD_RW_PORT     PORT(LCD_RW)

#define LCD_DATA_DDR    DDR(LCD_DATA)
#define LCD_E_DDR       DDR(LCD_E)
#define LCD_RS_DDR      DDR(LCD_RS)
#define LCD_RW_DDR      DDR(LCD_RW)

#define LCD_DATA_PIN    PIN(LCD_DATA)

#define SET_E() (LCD_E_PORT|=(1<<LCD_E_POS))
#define SET_RS() (LCD_RS_PORT|=(1<<LCD_RS_POS))
#define SET_RW() (LCD_RW_PORT|=(1<<LCD_RW_POS))

#define CLEAR_E() (LCD_E_PORT&=(~(1<<LCD_E_POS)))
#define CLEAR_RS() (LCD_RS_PORT&=(~(1<<LCD_RS_POS)))
#define CLEAR_RW() (LCD_RW_PORT&=(~(1<<LCD_RW_POS)))

#ifdef LCD_TYPE_162
    #define LCD_TYPE_204
#endif

#ifdef LCD_TYPE_202
    #define LCD_TYPE_204
#endif


void LCDByte(uint8_t c,uint8_t isdata)
{
//Sends a byte to the LCD in 4bit mode
//cmd=0 for data
//cmd=1 for command


//NOTE: THIS FUNCTION RETURS ONLY WHEN LCD HAS PROCESSED THE COMMAND

uint8_t hn,ln;          //Nibbles
uint8_t temp;

hn=c>>4;
ln=(c & 0x0F);

if(isdata==0)
    CLEAR_RS();
else
    SET_RS();

_delay_us(0.500);       //tAS

SET_E();

//Send high nibble

temp=(LCD_DATA_PORT & (~(0X0F<<LCD_DATA_POS)))|((hn<<LCD_DATA_POS));
LCD_DATA_PORT=temp;

_delay_us(1);           //tEH

//Now data lines are stable pull E low for transmission

CLEAR_E();

_delay_us(1);

//Send the lower nibble
SET_E();

temp=(LCD_DATA_PORT & (~(0X0F<<LCD_DATA_POS)))|((ln<<LCD_DATA_POS));

LCD_DATA_PORT=temp;

_delay_us(1);           //tEH

//SEND

CLEAR_E();

_delay_us(1);           //tEL

LCDBusyLoop();
}

void LCDBusyLoop()
{
    //This function waits till lcd is BUSY

    uint8_t busy,status=0x00,temp;

    //Change Port to input type because we are reading data
    LCD_DATA_DDR&=(~(0x0f<<LCD_DATA_POS));

    //change LCD mode
    SET_RW();       //Read mode
    CLEAR_RS();     //Read status

    //Let the RW/RS lines stabilize

    _delay_us(0.5);     //tAS

    
    do
    {

        SET_E();

        //Wait tDA for data to become available
        _delay_us(0.5);

        status=(LCD_DATA_PIN>>LCD_DATA_POS);
        status=status<<4;

        _delay_us(0.5);

        //Pull E low
        CLEAR_E();
        _delay_us(1);   //tEL

        SET_E();
        _delay_us(0.5);

        temp=(LCD_DATA_PIN>>LCD_DATA_POS);
        temp&=0x0F;

        status=status|temp;

        busy=status & 0b10000000;

        _delay_us(0.5);
        CLEAR_E();
        _delay_us(1);   //tEL
    }while(busy);

    CLEAR_RW();     //write mode
    //Change Port to output
    LCD_DATA_DDR|=(0x0F<<LCD_DATA_POS);

}

void LCDInit(uint8_t style)
{
    /*****************************************************************
    
    This function Initializes the lcd module
    must be called before calling lcd related functions

    Arguments:
    style = LS_BLINK,LS_ULINE(can be "OR"ed for combination)
    LS_BLINK :The cursor is blinking type
    LS_ULINE :Cursor is "underline" type else "block" type

    *****************************************************************/
    
    //After power on Wait for LCD to Initialize
    _delay_ms(30);
    
    //Set IO Ports
    LCD_DATA_DDR|=(0x0F<<LCD_DATA_POS);
    LCD_E_DDR|=(1<<LCD_E_POS);
    LCD_RS_DDR|=(1<<LCD_RS_POS);
    LCD_RW_DDR|=(1<<LCD_RW_POS);

    LCD_DATA_PORT&=(~(0x0F<<LCD_DATA_POS));
    CLEAR_E();
    CLEAR_RW();
    CLEAR_RS();

    //Set 4-bit mode
    _delay_us(0.3); //tAS

    SET_E();
    LCD_DATA_PORT|=((0b00000010)<<LCD_DATA_POS); //[B] To transfer 0b00100000 i was using LCD_DATA_PORT|=0b00100000
    _delay_us(1);
    CLEAR_E();
    _delay_us(1);
    
    //Wait for LCD to execute the Functionset Command
    LCDBusyLoop();                                    //[B] Forgot this delay

    //Now the LCD is in 4-bit mode

    LCDCmd(0b00001100|style);   //Display On
    LCDCmd(0b00101000);         //function set 4-bit,2 line 5x7 dot format

    /* Custom Char */
    LCDCmd(0b01000000);

    uint8_t __i;
    for(__i=0;__i<sizeof(__cgram);__i++)
        LCDData(__cgram[__i]);
    
    LCDGotoXY(0,0);

}
void LCDWriteString(const char *msg)
{
    /*****************************************************************
    
    This function Writes a given string to lcd at the current cursor
    location.

    Arguments:
    msg: a null terminated string to print

    Their are 8 custom char in the LCD they can be defined using
    "LCD Custom Character Builder" PC Software. 

    You can print custom character using the % symbol. For example
    to print custom char number 0 (which is a degree symbol), you 
    need to write

        LCDWriteString("Temp is 30%0C");
                                  ^^
                                  |----> %0 will be replaced by
                                        custom char 0.

    So it will be printed like.
        
        Temp is 30°C
        
    In the same way you can insert any syblom numbered 0-7  


    *****************************************************************/
 while(*msg!='\0')
 {
    //Custom Char Support
    if(*msg=='%')
    {
        msg++;
        int8_t cc=*msg-'0';

        if(cc>=0 && cc<=7)
        {
            LCDData(cc);
        }
        else
        {
            LCDData('%');
            LCDData(*msg);
        }
    }
    else
    {
        LCDData(*msg);
    }
    msg++;
 }
}

void LCDWriteInt(int val,unsigned int field_length)
{
    /***************************************************************
    This function writes a integer type value to LCD module

    Arguments:
    1)int val   : Value to print

    2)unsigned int field_length :total length of field in which the value is printed
    must be between 1-5 if it is -1 the field length is no of digits in the val

    ****************************************************************/

    char str[5]={0,0,0,0,0};
    int i=4,j=0;
    while(val)
    {
    str[i]=val%10;
    val=val/10;
    i--;
    }
    if(field_length==-1)
        while(str[j]==0) j++;
    else
        j=5-field_length;

    if(val<0) LCDData('-');
    for(i=j;i<5;i++)
    {
    LCDData(48+str[i]);
    }
}
void LCDGotoXY(uint8_t x,uint8_t y)
{
    if(x>=20) return;

    #ifdef LCD_TYPE_204
    
    switch(y)
    {
        case 0:
            break;
        case 1:
            x|=0b01000000;
            break;
        case 2:
            x+=0x14;
            break;
        case 3:
            x+=0x54;
            break;
    }

    #endif

    #ifdef LCD_TYPE_164
    switch(y)
    {
        case 0:
            break;
        case 1:
            x|=0b01000000;
            break;
        case 2:
            x+=0x10;
            break;
        case 3:
            x+=0x50;
            break;
    }

    #endif

    x|=0b10000000;
    LCDCmd(x);
}