Hi Guys today we will see GSM Interfacing with LPC2148.

Suggest To Read

• GSM Module Introduction
• Serial Communication

Components Required

• GSM SIM900A module
• LPC2148 Development Board

GSM Interfacing with LPC2148

Connection

Micro controller’s RX (P0.1) is connected into GSM module’s TX and Micro controller’s TX(P0.0) is Connected into GSM module’s RX pin.

Code

SMS Sending Code

This code is used to send the message to the particular number.

#include <lpc214x.h>

#define NUMBER "9876543210"          //Here insert your number where you want to send message

void ser_init(void);
void tx(unsigned char c);
unsigned char rx(void);
void tx_str(unsigned char *s);

void sms(unsigned char *num1,unsigned char *msg);
void gsm_delay(void);

unsigned int dell;

int main()
{
        ser_init();
        sms(NUMBER, "Welcome to the Embetronicx");
        while(1);
}

void sms(unsigned char *num1,unsigned char *msg)
{
    tx_str("AT");
    tx(0x0d);
    gsm_delay();

    tx_str("AT+CMGF=1");
    tx(0x0d);
    gsm_delay();

    tx_str("AT+CMGS=");
    tx('"');
    while(*num1)
        tx(*num1++);
    tx('"');
    tx(0x0d);
    gsm_delay();

    while(*msg)
        tx(*msg++);
    tx(0x1a);
    gsm_delay();
}

void gsm_delay()
{
    unsigned long int gsm_del,ff;
    for(gsm_del=0;gsm_del<=500000;gsm_del++)
         for(ff=0;ff<25;ff++);
}

void ser_init()
{
    VPBDIV=0x02;      //PCLK = 30MHz
    PINSEL0=0x5;
    U0LCR=0x83;
    U0DLL=195;
    U0DLM=0;
    U0LCR=0x03;
    U0TER=(1<<7);
}

void tx(unsigned char c)
{
    U0THR=c;
    while((U0LSR&(1<<5))==0);
}

void tx_str(unsigned char *s)
{
    while(*s) {
        tx(*s++);
    }
}

unsigned char rx()
{
    while((U0LSR&(1<<0))==0);
    return U0RBR;
}

Calling Code

This code is used to Call to the particular number.

#include <lpc214x.h>

#define NUMBER "9876543210"          //Here insert your number where you want to send message

void ser_init(void);
void tx(unsigned char c);
unsigned char rx(void);
void tx_str(unsigned char *s);

void call(unsigned char *num2);
void gsm_delay(void);

unsigned int dell;

int main()
{
        ser_init();
        call(NUMBER);
        while(1);
}

void call(unsigned char *num2)
{
    tx_str("AT");
    tx(0x0d);
    gsm_delay();

    tx_str("AT+CMGF=1");
    tx(0x0d);
    gsm_delay();

    tx_str("ATD");
    while(*num2)
        tx(*num2++);
    tx(';');
    tx(0x0d);
    for(dell=0;dell<=30;dell++)
        gsm_delay();

    tx_str("ATH");
    tx(0x0d);
    gsm_delay();
}

void gsm_delay()
{
    unsigned long int gsm_del,ff;
    for(gsm_del=0;gsm_del<=500000;gsm_del++)
         for(ff=0;ff<25;ff++);
}

void ser_init()
{
    VPBDIV=0x02;      //PCLK = 30MHz
    PINSEL0=0x5;
    U0LCR=0x83;
    U0DLL=195;
    U0DLM=0;
    U0LCR=0x03;
    U0TER=(1<<7);
}

void tx(unsigned char c)
{
    U0THR=c;
    while((U0LSR&(1<<5))==0);
}

void tx_str(unsigned char *s)
{
    while(*s) {
        tx(*s++);
    }
}

unsigned char rx()
{
    while((U0LSR&(1<<0))==0);
    return U0RBR;
}

That’s guys… You can use this code for send a message and call to particular number. If you have any doubt please comment below.