pic18+ds1307+lcd: I am facing a problem in my program.

[ARAVINDHANK]

The LCD is displaying time and date along with some symbols in between in a fluctuating manner. Please some one help me to solve the problem.

#include <p18f4520.h>
#include <delays.h>
#include <i2c.h> 
#include <stdio.h> 
//#define _XTAL_FREQ 4000000 // 4 MHz clock 

//__CONFIG(0X3F39);
#define LCD_EN PORTCbits.RC2
#define	LCD_RS PORTCbits.RC0
#define	LCD_RW PORTCbits.RC1
#define LCD_DATA LATD
#define	LCD_STROBE()	((LCD_EN = 1),(LCD_EN=0))
unsigned char date [5] = {"Date:"};
unsigned char time [5] = {"Time:"};

unsigned char I2CData[]= {0x00,0x01,0x40,0x03,0x04,0x05,0x06};
unsigned char I2CInitval[]= {0x00,0x00,0x12,0x01,0x23,0x01,0x13};
unsigned char tmp;
unsigned char i;
unsigned int j;
void MSDelay(unsigned int itime)
{
unsigned int i,j;

for(i=0;i<itime;i++)
for(j=0;j<135;j++);
}
void I2CWait(){
        while ( ( SSPCON2 & 0x1F ) || ( SSPSTAT & 0x04 ) );		/* wait for any pending transfer */

}

void I2CInit(void){
        TRISCbits.TRISC3 = 1;      	/* SDA and SCL as input pin */
        TRISCbits.TRISC4 = 1;      	/* these pins can be configured either i/p or o/p */
        SSPSTAT |= 0x80; 	/* Slew rate disabled */
        SSPCON1 = 0x28;   	/* SSPEN = 1, I2C Master mode, clock = FOSC/(4 * (SSPADD + 1)) */
        SSPADD = 0x28;    	/* 100Khz @ 4Mhz Fosc */
}

void I2CStart(){
		I2CWait(); 
        SSPCON2bits.SEN = 1;         	
        while(SSPCON2bits.SEN);    /*Start Condition Enable*/
                    	
}

void I2CStop(){
        SSPCON2bits.PEN = 1;         	/* Stop condition enabled */
        while(SSPCON2bits.PEN);      	/* Wait for stop condition to finish */
                     		/* PEN automatically cleared by hardware */
}

void I2CRestart(){
        SSPCON2bits.RSEN = 1;        	/* Repeated start enabled */
        while(SSPCON2bits.RSEN);     	/* wait for condition to finish */
}

void I2CAck(){
        SSPCON2bits.ACKDT = 0;       	/* Acknowledge data bit, 0 = ACK */
        SSPCON2bits.ACKEN = 1;       	/* Ack data enabled */
        while(SSPCON2bits.ACKEN);    	/* wait for ack data to send on bus */
}

void I2CNak(){
        SSPCON2bits.ACKDT = 1;       	/* Acknowledge data bit, 1 = NAK */
        SSPCON2bits.ACKEN = 1;       	/* Ack data enabled */
        while(SSPCON2bits.ACKEN);    	/* wait for ack data to send on bus */
}

void I2CSend(unsigned char dat){
	
        SSPBUF = dat;    		/* Move data to SSPBUF */
        while(SSPSTATbits.BF);       		/* wait till complete data is sent from buffer */
        I2CWait();       		/* wait for any pending transfer */
}

unsigned char I2CRead(void){
		I2CWait(); 						/* Reception works if transfer is initiated in read mode */
        SSPCON2bits.RCEN = 1;        		/* Enable data reception */
        while(!SSPSTATbits.BF);      		/* wait for buffer full */
        return SSPBUF;   		/* Read serial buffer and store in temp register */
        	     				/* wait to check any pending transfer */	     
}

void lcddata(unsigned char value)
	{

LCD_DATA = value;
LCD_RS = 1; 
LCD_RW = 0;
LCD_EN = 1;
MSDelay(1);
LCD_EN = 0;

	}

void lcdcmd(unsigned char value)
	{
LCD_DATA = value;
LCD_RS = 0;
LCD_RW = 0;
LCD_EN = 1;
MSDelay(1);
LCD_EN = 0;

	}

void bcdToascii(unsigned char value){

	tmp = value;
	tmp = tmp & 0xf0;
	tmp = tmp >> 4;
	tmp = tmp | 0x30;
	lcddata(tmp);
	tmp = value;
	tmp = tmp & 0x0f;
	tmp = tmp | 0x30;
	lcddata(tmp);

}


void lcd_init(){

	TRISD	= 0;
	TRISB	= 0;
	TRISCbits.TRISC7  = 0;
	TRISCbits.TRISC6  = 0;
	LCD_EN =0;
	MSDelay(175);
	lcdcmd(0x38);
	lcdcmd(0x0c);
	lcdcmd(0x01);
	lcdcmd(0x80);
				}


void I2Cwrite(){
											/* Initialize I2C Port */
 		I2CStart();						/* Send Start condition */
        I2CSend(0xD0);					/* Send DS1307 slave address with write operation */
        I2CSend(0x00);						/* Send subaddress 0x00, we are writing to this location */
			for(i=0;i<8;i++) {			/* Loop to write 8 bytes */
            	I2CSend(I2CInitval[i]);							/* send I2C data one by one */			
        }
			I2CStop();							/* Send a stop condition - as transfer finishes */
}
void display (){
	unsigned int i,j;
	lcdcmd(0x80);
	for (i=0;i<5;i++)
			{
		lcddata(time[i]);
			}
	bcdToascii(I2CData[2]);
	lcddata(':');
	bcdToascii(I2CData[1]);
	lcddata(':');
	bcdToascii(I2CData[0]);
	
	lcdcmd(0xc0);
	for (j=0;j<5;j++)
			{
		lcddata(date[j]);
			}
	bcdToascii(I2CData[4]);
	lcddata('-');
	bcdToascii(I2CData[5]);
	lcddata('-');
		
	lcddata('2');lcddata('0');
//bcdToascii(I2CData[5]);
	bcdToascii(I2CData[6]);
}
void I2Cread(){
        I2CStart();
		I2CSend(0xD0);							/* Send slave address with write */ /* Send address for dummy write operation *//* this address is actually where we are going to read from */					       						       
        I2CSend(0x00);							/* Send a repeated start, after a dummy write to start reading */
        I2CRestart();
        I2CSend(0xD1);										/* send slave address with read bit set */
  
			for(i=0;i<7;i++) 
				{
      			I2CData[i] = I2CRead();			/* read a byte */								/* ACK if its not the last byte to read */             	 
				I2CAck();    
				}
			//I2CData[i] = I2CRead(); /*this line when enabled, makes the timer to reset after 2 minutes but LCD faces no fluctuation in displaying*/	
			I2CNak();
	 		I2CStop(); /* Send stop */								
}

void main(){ 
TRISCbits.TRISC0  = 0;
TRISCbits.TRISC1  = 0;
TRISCbits.TRISC2  = 0;
        I2CInit();
        lcd_init();       
		I2Cwrite();
display();
lcdcmd(0x94);
		lcddata('A');
while(1){

        I2Cread();
		display();
				
}
}

 

[jayanth.devarayanadurga]

Post the screenshot of the LCD Displying data.

 

[ARAVINDHANK]

This is the screen shot of the LCD.

 

[jjeevan007]

can u post the circuit........

 

[jayanth.devarayanadurga]

Have you connected pullup resistors to SCL and SDA lines? Have you written the time to ds1307? Are you using C18 compiler?

When you call i2c_write() it has i2c_stop() function inside. So the i2c is stopped. Then when you call i2c_read() it has i2c_start() inside and i2c is started. But that is not the way. You should not stop and start the i2c. remove the stop_i2c() from i2c_write() and remove i2c_start() from i2c_read()

 

[babar_ali]

In your Code I dont see you sending ACK and NACK command to the Slave (DS1307). After sending a byte to ds1307 send ACK command.
here is what you can do

void I2Cwrite()
{
						/* Initialize I2C Port */
I2CStart();						/* Send Start condition */
I2CSend(0xD0);					/* Send DS1307 slave address with write operation */
I2CSend(0x00);						/* Send subaddress 0x00, we are writing to this location */
for(i=0;i<8;i++) {			/* Loop to write 8 bytes */
            	I2CSend(I2CInitval[i]);
	I2CAck();				/* send I2C data one by one */			
        }

 

[zuisti]

The LCD is displaying time and date along with some symbols in between in a fluctuating manner.

Dear ARAVINDHANK;

You made ​​one(?) usual fatal error in your code:

.....
unsigned char I2CData[]   = {0x00,0x01,0x40,0x03,0x04,0x05,0x06};
unsigned char I2CInitval[]= {0x00,0x00,0x12,0x01,0x23,0x01,0x13};
       [COLOR="#0000FF"]The above arrays have[/COLOR] [COLOR="#FF0000"]7[/COLOR] [COLOR="#0000FF"]emements: name[0] to[/COLOR] [COLOR="#FF0000"]name[6] !!!!!!!!!![/COLOR]
.....
void I2Cwrite(){
.....
     for(i=0;i < [COLOR="#FF0000"]8[/COLOR] ;i++) { /* Loop to write [COLOR="#FF0000"]8[/COLOR] bytes */
        I2CSend(I2CInitval[i]); [COLOR="#FF0000"]//the last I2CInitval[7] is a garbage !!![/COLOR]
     }
...
}
.....
void I2Cread(){
.....
    for(i=0;i<7;i++) {
	
      I2CData[i] = I2CRead();	 [COLOR="#0000FF"]// OK, the last I2CData[6] is valid[/COLOR]
      I2CAck();    
    }

/*this line when enabled, makes the timer to reset after 2 minutes but LCD faces no fluctuation ..*/
    //I2CData[i] = I2CRead(); 
[COLOR="#FF0000"]//because now 'i' is equal to 7 and I2CData[7] is an invalid address, overwrite anything.[/COLOR]
....
}

Better to get any help: upload your DSN and also the source.
zuisti