If you observe, you can see an inscription on the side of each set of pins. In the picture you attached, you can see P2, P3 and P4. For example, looking at the description P2 on the board you will see that there is a number 6 on the side, this number corresponds to the pin that is on your side, therefore the pin side of the P2 registration will be number 5, this way you discover a pattern of group numbers pins. Easy is not it?
I hope it helps you. And feel free to ask again.
// this code is for sending and receiving a SMS + sending back (my code)
#include<p18f4550.h>
#include<delays.h>
#define FREQ 12000000
#define baud 9600
#define spbrg_value (((FREQ/64)/baud)-1)
#pragma config PLLDIV = 3
#pragma config CPUDIV = OSC1_PLL2
#pragma config FOSC = HS
#pragma config MCLRE = ON
#pragma config WDT = OFF, DEBUG = OFF
#pragma config LVP = OFF
#pragma config PWRT = OFF
#pragma config PBADEN = OFF
#pragma config ICPRT = OFF
// defining LCD PORT
//---------------------------------
#define ldata PORTD
#define rs PORTCbits.RC0
#define rw PORTCbits.RC1
#define en PORTCbits.RC2
#define send PORTBbits.RB1
#define rec PORTBbits.RB2
//Defining the LCD commands
//------------------------------------------
void lcdcmd(unsigned char value)
{
ldata = value;
rs = 0;
rw = 0;
en = 1;
Delay100TCYx( 30 );
en = 0;
}
//Defining the LCD display
//------------------------------------------
void lcddata(unsigned char value)
{
ldata = value;
rs = 1;
rw = 0;
en = 1;
Delay100TCYx( 30 );
en = 0;
}
// LCD initialization
// ------------------------------
void lcd_ini()
{
lcdcmd(0x38); //LCD matrix
Delay10KTCYx( 75 );
lcdcmd(0x0E); //Blink curser
Delay10KTCYx( 4 );
lcdcmd(0x01); //Clear LCD
Delay10KTCYx( 4 );
lcdcmd(0x06); //increment curser
Delay10KTCYx( 4 );
lcdcmd(0x80); //start at firs line, first position
Delay10KTCYx( 4 );
}
// define serial communication ( receiving data from GPS)
//---------------------------------------
unsigned char rx_data(void); //receiving data function
void tx_data(unsigned char serial_data); // Transmit data function
void display( unsigned char array[], int size); // to display any string on LCD
void transmit( unsigned char array2[], int size2); // to send any string to TX pin
unsigned char ch=0;
int i=0,j,k;
unsigned char welcome[]=" Welcome ";
unsigned char choice[]="Send or receive? ";
unsigned char sending[]=" Sending .. ";
unsigned char waiting[]=" Waiting for SMS";
unsigned char sms_received[]=" SMS Received ";
unsigned char sending_back[]=" Sending Back: Hello";
unsigned char double_qoutes[]="\""; // to print "
unsigned char sms_send[]="AT+CMGS=";
unsigned char sms_format[]="AT+CMGF=1\r"; // TEXT mode
unsigned char sms_write[]="AT+CMGS=\"xxxxxxxxxx\"\r"; // 10-Digit Mobile Number
unsigned char sms[]="Hello\r";
unsigned char sms_report[]="SMS Sent...";
unsigned char sms_indication[]="AT+CNMI=1,2,0,0,0\r";
unsigned char phone_number[10];
unsigned char stringArray[46]; //to store the received sms information
unsigned char text[2]; // to store the text message
unsigned char sms_terminate=0x1A;
unsigned char enter=0x0D;
void main()
{
TRISD = 0; //Set it output for the LCD
TRISCbits.RC0 = 0; //Set it output for RS
TRISCbits.RC1 = 0; //Set it output for RW
TRISCbits.RC2 = 0; //Set it output for en
TRISCbits.RC6 = 0; //TX pin set as output
TRISCbits.RC7 = 1; //RX pin set as input
TRISBbits.RB1 = 1; // To send an SMS
TRISBbits.RB2= 1; // To Receive an SMS
// serial communicatin configuration
SPBRG=spbrg_value; //Fill SPBRG register to set the baud rate
RCSTAbits.SPEN=1; // To activate serial port (Tx and Rx pins)
RCSTAbits.CREN=1; // to enable continous receiving
TXSTA=0x24; // To enable transmition & low baud rate + 8-bits
lcd_ini();
Delay10KTCYx( 250);
display( welcome, sizeof(welcome));
Delay10KTCYx( 250);
Delay10KTCYx( 250);
Delay10KTCYx( 250);
while(1)
{
lcdcmd(0x01);
lcdcmd(0x80);
Delay10KTCYx( 250);
display( choice, sizeof(choice));
Delay10KTCYx( 250);
if(send==1)
{
lcdcmd(0x01);
lcdcmd(0x80);
Delay10KTCYx( 250);
display(sending, sizeof(sending));
Delay10KTCYx( 250);
transmit(sms_format, sizeof(sms_format)); // to set the mode
Delay10KTCYx( 250);
transmit(sms_write, sizeof(sms_write));
Delay10KTCYx( 250);
transmit(sms, sizeof(sms));
tx_data(sms_terminate);
lcdcmd(0x01);
lcdcmd(0x80);
Delay10KTCYx( 250);
display(sms_report, sizeof(sms_report));
Delay10KTCYx( 250);
Delay10KTCYx( 250);
}
if(rec==1)
{
lcdcmd(0x01);
lcdcmd(0x80);
Delay10KTCYx( 250);
display(waiting, sizeof(waiting));
transmit(sms_format, sizeof(sms_format)); // to set the mode
transmit(sms_indication, sizeof(sms_indication));
ch = rx_data();
if(ch == '+')
{
do
{
ch = rx_data();
}while(ch != '\n');
i = 0;
do
{
text[i++] = rx_data();
}while(i < 2 );
}
lcdcmd(0x01);
lcdcmd(0x80);
Delay10KTCYx( 250);
display(text, sizeof(text));
Delay10KTCYx( 250);
Delay10KTCYx( 250);
}
} //end while1
}// end main function
//------ methods ---------
unsigned char rx_data(void)
{
while(PIR1bits.RCIF==0); // Wait until RCIF gets low
return RCREG; // Store data in Reception register
}
void tx_data(unsigned char serial_data) // Transmit data function
{
TXREG=serial_data;
while(PIR1bits.TXIF==0);
}
void display( unsigned char array[], int size)
{
for(i=0; i<size; i++)
{
lcddata(array[i]);
}
}
void transmit( unsigned char array2[], int size2)
{
for(i=0; i<size2; i++)
{
tx_data(array2[i]);
}
}