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LCD Not working 18f4620 C18

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xabia

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hi all i am using c18 picdem z lcd18

i cant get my lcd working display out

i had do a online search but simply cant work


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#include <p8h> 
#include <portb.h>
#include <delays.h>
 
#pragma config OSC = XT
#pragma config WDT = OFF
#pragma config LVP = OFF
#pragma config DEBUG = ON
#pragma config PBADEN   =   OFF // PORTB<4:0> pins are configured as digital I/O on Reset)
 
#define TRIS_RW  TRISDbits.TRISD5       /* TRIS for RW */
#define TRIS_RS  TRISDbits.TRISD4       /* TRIS for RS */
#define TRIS_E   TRISDbits.TRISD6       /* TRIS for E  */
 
#define RW_PIN   LATDbits.LATD5         /* PORT for RW */
#define RS_PIN   LATDbits.LATD4         /* PORT for RS */
#define E_PIN    LATDbits.LATD6         /* PORT for E  */
 
#define DB7 LATDbits.LATD3
#define DB6 LATDbits.LATD2
#define DB5 LATDbits.LATD1
#define DB4 LATDbits.LATD0
 
// PORTD0 - DB4
// PORTD1 - DB5
// PORTD2 - DB6
// PORTD3 - DB7
// PORTD4 - RS
// PORTD5 - RW
// PORTD6 - EN
 
#define SWITCH PORTBbits.RB4 
#define SWITCH_1 PORTBbits.RB5
#define LED1 PORTAbits.RA0 
#define LED2 PORTAbits.RA1 
 
void lcd_send(far rom char *str);
void delay_20us(unsigned int);
void sendChar(unsigned char);
 
void clr_screen(void);
void clr_scr(unsigned char);
 
void send_cmd(unsigned char, unsigned char);
void welcome_title(void);
void send_lcd(unsigned char, unsigned char); 
void write_data(far rom char *str, unsigned char);  
void lcd_init(void);
void line_no(int);
void nop(void);
void clear_lcd(int);
void latch_E(void);
void delay_ms(unsigned int duration);
void display_lcd(void);
 
 /* global variables */ 
 
void main(void)
{
 
    INTCON2bits.RBPU=0; //Enable pull up for PB
    ADCON1=0x0f;            //Digital output
    LATB=0b00000000;        //Clear portb 
    LATA=0b00000000;        //Clear porta 
    TRISB=0b00110000;       //PORTB BIT4 and 5 AS INPUT, THE OTHERS ARE OUTPUT    
    TRISA=0b00000000;       //PORTA OUTPUT, LED
    TRISD=0x00;         //PORTD is output, LCD 
    TRISE=0x00;         //PORTE PSP not active 
    LATD=0x00;
    
    // initialisation start
    Delay10TCYx(200);
    lcd_init();
    delay_ms(15);
    //initialisation end
 
    welcome_title();
 
while(1)
  {
    if(SWITCH==0 & SWITCH_1==0)    
    { 
        //LED1=0, LED2=0;       //Clear both LED
        LATA = 0x00;
    } 
    else if(SWITCH==0) //RB4 button
    {
        //LED1=1, LED2=0;   //RA0 LED true
        LATA = 0x01;
        clr_scr(3);
    }
    else if(SWITCH_1==0) //RB5 button
    {
            //RA1 LED true
        LATA = 0x02;
        write_data("AA", 1);
        
    }
  }  
}
 
void lcd_init(void) // 4bit mode
{
    //function set
    LATD=0b00000000;
Delay10TCYx(500);
    send_cmd(0b00110000, 0);
Delay10TCYx(500);
    send_cmd(0b00110000, 0);
Delay10TCYx(500);
    send_cmd(0b00110000, 0); // 2 lines, 5x8 dots
Delay10TCYx(500);
send_cmd(0b00110000, 0); // 2 lines, 5x8 dots
send_cmd(0b00110000, 0); // 2 lines, 5x8 dots
    // display on/off control
    send_cmd(0x28, 0);
    //send_cmd(0b11100000, 0); // Display on, cursor on, blink off
    send_cmd(0x0F, 0); // Display on, cursor off, blink off
    // Entry mode
    send_cmd(0x01, 0); 
    send_cmd(0x0C, 0);// increment mode, shift off
}
 
void enable(void)
{
  E_PIN = 1;
  Delay10TCYx(1);
  E_PIN = 0;
}
 
void send_cmd(unsigned char b, unsigned char c) 
{
    unsigned int tempdata=b;
    RS_PIN = c; //Command mode = 0
                //To write address = 1
    LATD = ((LATD & 0xF0) | ((b >> 4) & 0x0F)) ;
    latch_E();
    delay_ms(10);
}
 
 
void lcd_send(far rom char *str)
{
  int index = 0;
  while (str[index] != '\0')
  {
     sendChar(str[index]);
     index++;
  }
}
 
void clr_screen(void)
{
  int index = 0;
    //for (index=0; index<16; index++)
    while (index != 16)
     {
        sendChar(' '); // write blank
        index++;
     }
}
 
void clr_scr(unsigned char b)
{
    unsigned char index =0;
 
    //send_lcd (0x80,0); 
    if ((b == 1) || (b == 3))
    {
        line_no(1);
        while (index != 16)
        {
            sendChar(' '); // write blank
            index++;
        }
    }
    if ((b == 2) || (b ==3) )
    {
        //send_lcd (0xC0,0); 
        line_no(2);
        index=0;
        while (index != 16)
        {
            sendChar(' '); // write blank
            index++;
        }
    }
}
 
 
void sendChar(unsigned char b)
{
     RS_PIN = 1;
     DB7 = (b >> 7) & 1;
     DB6 = (b >> 6) & 1;
     DB5 = (b >> 5) & 1;
     DB4 = (b >> 4) & 1;
     latch_E();
     DB7 = (b >> 3) & 1;
     DB6 = (b >> 2) & 1;
     DB5 = (b >> 1) & 1;
     DB4 = (b & 1);
     latch_E();
     Delay10TCYx(80);
}
 
void line_no(int b) 
{
    if (b == 2)
    {
      send_lcd(0b11000000,0); //1100 0000 - move cursor to 2nd line
    }
    else
    {
      send_lcd(0b10000000,0); //1000 0000 - move cursor to 1st line
    }
}
 
void latch_E(void)
{
    E_PIN=1;
    Delay10TCYx(1); 
    E_PIN=0;
}
 
 /* write data on lcd */ 
void send_lcd(unsigned char b,unsigned char rs_con)  
{   
    unsigned int tempdata = b; 
    RS_PIN = rs_con;   // set RS 
                        //0 = set address
                        //1 = write data  
    RW_PIN = 0;    // clear RW - write mode 
    LATD = ((LATD & 0xF0) | ((b >> 4) & 0x0F)) ;
    //DelayFor18TCY(); 
    latch_E();
    LATD  = (LATD & 0xF0) | (tempdata & 0x0F); 
    Delay100TCYx(2); 
    latch_E();
    Delay1KTCYx(2);      // alternate to check busy flag.. if lcd doesnt work properly, inc/dec this delay 
} 
 
/* Welcome*/ 
void welcome_title(void)  
{   
    unsigned char index; 
    unsigned char a[16] = "Hello"; 
    unsigned char b[16] = "123";   
    index=0;
    //send_lcd (0x80,0); 
    line_no(1);
    while (a[index] != '\0')
    {
       send_lcd (a[index],1); 
       index++;
    }
    //send_lcd (0xC0,0); 
    line_no(2);
    index=0;
    while (b[index] != '\0')
    {
        send_lcd (b[index],1); 
       index++;
    }
} 
 
void write_data(far rom char *str, unsigned char c)  
{   
    unsigned char index;
    index =0;
    //send_lcd (0x80,0); 
    if (c == 2) 
    {
        clr_scr(2);
        line_no(2);
    }
    else
    {
        clr_scr(1);
        line_no(1);
    }
    while (str[index] != '\0')
    {
       send_lcd (str[index],1); 
       index++;
    }
} 
 
 
void delay_ms(unsigned int duration) // delay in miliseconds for 4.0MHZ crystal
{
    unsigned int i;
    for(;duration!=0;duration--)
    {
        for(i=0;i<=50;i++)
        {
            _asm
                nop
                nop
                nop
            _endasm
        }
        _asm
            nop
            nop
        _endasm
    }
}
 
void nop(void)
{
        _asm
            nop
        _endasm
}
 
void delay_20us(unsigned int duration) // delay in 20u for 4.0MHZ crystal
{
    unsigned int i;
    for(;duration!=0;duration--)
    {
        _asm
            nop
        _endasm 
    }
}



Attached is my datasheet for the LCDView attachment LCD.pdf

Appreciate your help.
thx
 
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bigdogguru

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Does the LCD display anything at all, black boxes perhaps?

lcdblackboxes2.jpg

BigDog
 

xabia

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yes it is showing when i connected it to the Vo
 

bigdogguru

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Vo is the contrast control.

You should have Vo attached to the wiper arm of a 10KΩ pot with the other two leads of the pot attached to Vdd and Vss.

Is that the way it is configured?

The black boxes indicate the LCD was not properly initialized.

BigDog
 

xabia

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yes i have a trimmer from 10k to 20k
yeah i think i didn't initialize it
but i am struck on getting it work
 

bigdogguru

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I believe one issue is your sendchar() routine:

Code:
void sendChar(unsigned char b)
{
     RS_PIN = 1;
     DB7 = (b >> 7) & 1;
     DB6 = (b >> 6) & 1;
     DB5 = (b >> 5) & 1;
     DB4 = (b >> 4) & 1;
     latch_E();
     DB7 = (b >> 3) & 1;
     DB6 = (b >> 2) & 1;
     DB5 = (b >> 1) & 1;
     DB4 = (b & 1);
     latch_E();
     Delay10TCYx(80);
}

The most significant nybble (upper four bits) first, followed by the least significant nybble (lower four bits).

You might try something like the following routines:

Code:
//LCD Control pins
#define rs LATA.F0
#define rw LATA.F1
#define en LATA.F2

//LCD Data pins
#define lcdport LATB

void lcd_ini();
void dis_cmd(unsigned char);
void dis_data(unsigned char);
void lcdcmd(unsigned char);
void lcddata(unsigned char);

void main(void)
{
	unsigned char data0[]="EngineersGarage";
	unsigned int i=0;
	TRISB=0;			// Configure Port B as output port
	LATB=0;
	Delay_ms(100);
	lcd_ini();			// LCD initialization
	while(data0[i]!='\0')
	{
		dis_data(data0[i]);
		Delay_ms(200);
		i++;
	}
}
void lcd_ini()	                    
{
	dis_cmd(0x02);		// To initialize LCD in 4-bit mode.
	dis_cmd(0x28);		// To initialize LCD in 2 lines, 5x7 dots and 4bit mode.
	dis_cmd(0x0C);
	dis_cmd(0x06);
	dis_cmd(0x80);
}

void dis_cmd(unsigned char cmd_value)
{
	unsigned char cmd_value1;
	cmd_value1 = (cmd_value & 0xF0);	// Mask lower nibble because RB4-RB7 pins are being used
	lcdcmd(cmd_value1);			// Send to LCD
	cmd_value1 = ((cmd_value<<4) & 0xF0);	// Shift 4-bit and mask
	lcdcmd(cmd_value1);			// Send to LCD
}


void dis_data(unsigned char data_value)
{
	unsigned char data_value1;
	data_value1=(data_value&0xF0);
	lcddata(data_value1);
	data_value1=((data_value<<4)&0xF0);
	lcddata(data_value1);
}

void lcdcmd(unsigned char cmdout)
{
	lcdport=cmdout;		//Send command to lcdport=PORTB
	rs=0;						
	rw=0;
	en=1;
	Delay_ms(10);
	en=0;
}

void lcddata(unsigned char dataout)
{
	lcdport=dataout;	//Send data to lcdport=PORTB
	rs=1;
	rw=0;
	en=1;
	Delay_ms(10);
	en=0;
}

Personally I prefer to use the busy flag, but the appropriate delay will suffice.

BigDog
 

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