How to interface GPS with PIC18F4550 Microcontroller

[sdfsdfsf]

I follow the below website to do.

 

 

But, the program did not work.

The following problem will appear.

Have anyone can help me to fix these problem???

 

[sdfsdfsf]

The code.

 

// Program to Interface GPS with PIC18F4550 Microcontroller
#define FREQ 12000000
#define baud 4800
#define spbrg_value (((FREQ/64)/baud)-1)
#define rs LATA.F0
#define rw LATA.F1
#define en LATA.F2
#define lcdport LATB

unsigned char rx_data();
void lcd_ini();
void lcdcmd(unsigned char);
void lcddata(unsigned char);

unsigned char longi_data[12];
unsigned char lati_data[12];
unsigned char data,value=0;
unsigned int i=0,pos;

void main()
{
        TRISB=0;                  // Set Port B as output port
        LATB=0;
        TRISA=0;
        LATA=0;
        SPBRG=spbrg_value;               // Fill SPBRG register to set the baud rate
        RCSTA.SPEN=1;                        // To activate serial port (Tx and Rx pins)                                   
        RCSTA.CREN=1;                       // To enable continuous reception
        lcd_ini();
        while(1)
        {
                data=rx_data();                     // Check the string ‘$GPGGA,’
                if(data==’$’)
                {
                        data=rx_data();
                        if(data==’G’)
                        {
                                data=rx_data();
                                if(data==’P’);
                                {
                                        data=rx_data();
                                        if(data==’G’);
                                        {
                                                data=rx_data();
                                                if(data==’G’)
                                                {
                                                data=rx_data();
                                                if(data==’A’)
                                                {
                                                data=rx_data();
                                                if(data==’,’)
                                                {
                                                data=rx_data();
                                                while(data!=’,’)
                                                data=rx_data();
                                                for(i=0;data!=’N’;i++)
                                                data=rx_data();
                                                lati_data=data;  // Store the Latitude data
                                                }
                                                data=rx_data();
                                                if(data==’,’)
                                                {
                                                for(i=0;data!=’E’;i++)
                                                {
                                                data=rx_data();
                                                longi_data=data;  // Store the Longitude data
                                                }
                                                }
                                                i=0;
                                                lcdcmd(0x80);
                                                while(i<11)
                                                {
                                                lcddata(lati_data);       // Print the Latitude data
                                                i++;
                                                }
                                                i=0;
                                                lcdcmd(0xC0);
                                                while(i<12)
                                                {
                                                lcddata(longi_data);      // Print the Longitude data
                                                i++;
                                                }
                                                }
                                                }
                                                }
                                        }
                                }
                        }
                }
                Delay_ms(1000);
                for(i=0;i<12;i++)
                {
                        data=0;
                        lati_data=0;
                        longi_data=0;
                }
        }
}

unsigned char rx_data(void)
{
        while(PIR1.RCIF==0);              // Wait until RCIF gets low
        return RCREG;                 // Store data in Reception register
}

void lcd_ini()
{
        lcdcmd(0x38);         // Configure the LCD in 8-bit mode, 2 line and 5×7 font
        lcdcmd(0x0C);         // Display On and Cursor Off
        lcdcmd(0x01);         // Clear display screen
        lcdcmd(0x06);         // Increment cursor
        lcdcmd(0x80);         // Set cursor position to 1st line, 1st column
}

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;
}

 

[AJISH ALFRED]

 

Hi,

Both the images are not legible. Better you post the link and describe the problem which you face.

[sdfsdfsf]

The 1602LCD will show this.

wysiwyg_imageupload:5583:

[AJISH ALFRED]

 

LCD not initialized!

 

Check your circuit connections.

 

Still not working, then modify the lcdcmd() function as shown below.

 

void lcdcmd(unsigned char cmdout)
{
        lcdport=cmdout;             //Send command to lcdport=PORTB
        rs=0;                                               
        rw=0;

        Delay_ms(10);               //add a delay here also
        en=1;
        Delay_ms(10);
        en=0;
}

 

Also make sure that the PORTB, rs, rw, en are properly set as output, and the function Delay_ms() is generating millisecond delays as much as the parameter given in the function call.

[AJISH ALFRED]

 

Still not working, then modify the lcdcmd() function again as shown below.

 

void lcdcmd(unsigned char cmdout)
{
        lcdport=cmdout;             //Send command to lcdport=PORTB
        rs=0;                                               
        rw=0;

        Delay_ms(10);               //add a delay here also
        en=1;
        Delay_ms(10);
        en=0;

        Delay_ms(10);               //add a delay here also
}

 

Make sure that you are using the same kind of lcd module.

All you need is to get rid off that black boxes from lcd.

Still there is black boxes, then there is some mistake in your hardware.

[Author]

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