I want modulate this code ( interfacing at89c51 with gsm )

[Mohammed_]

Hi

In my project will be there two switches. One for send AT to gsm to make sure the gsm is work and switch number two when it`s 1 will send AT commands to send a message to a specific number.

Now I`ll explain more.

see this link .. **broken link removed**

I`ll use this circuit, in P1.6 here will be switch if 1 it will send AT to gsm ounce after that I want the response show on LCD.
And in P1.7 another switch, if 1 send AT+CMGF=1 then show response on lcd , then send AT+CMGW="+*********", then send a written message example "Hi".
See this link .. HERE



Code is here .. **broken link removed**







// Program to Interface GSM Module with 8051 microcontroller (AT89C51) without using PC

#include<reg51.h>
#define port P1
#define dataport P2 // Data port for LCD
sbit rs = port^2;
sbit rw = port^3;
sbit en = port^4;
int count,i;
unsigned char check,str[15];
bit check_space;

void init_serial() // Initialize serial port
{
TMOD=0x20; // Mode2
TH1=0xfd; // 9600 baud
SCON=0x50; // Serial mode=1 ,8-Bit data,1 Stop bit ,1 Start bit, Receiving on
TR1=1; // Start timer
}
void delay(unsigned int msec) // Function for delay
{
int i,j;
for(i=0;i<msec;i++)
for(j=0; j<1275; j++);
}

void lcd_cmd(unsigned char item) // Function to send command on LCD
{
dataport = item;
rs= 0;
rw=0;
en=1;
delay(1);
en=0;
return;
}

void lcd_data(unsigned char item) // Function to display character on LCD
{
dataport = item;
rs= 1;
rw=0;
en=1;
delay(1);
en=0;
return;
}

void lcd_data_string(unsigned char *str) // Function to display string on LCD
{
int i=0;
while(str!='\0')
{
lcd_data(str);
i++;
delay(10);
}
return;
}
void lcd()
{
lcd_cmd(0x38); // For using 8-bit 2 row LCD
delay(5);
lcd_cmd(0x0F); // For display on cursor blinking
delay(5);
lcd_cmd(0x80); // Set the cursor on first position of LCD
delay(5);
}

void transmit_data(unsigned char str) // Function to transmit data through serial port
{
SBUF=str; //Store data in SBUF
while(TI==0); //Wait till data transmits
TI=0;
}

void receive_data() interrupt 4 // Function to recieve data serialy from RS232 into microcontroller
{
RI=0;
str[++count]=SBUF; //Read SBUF

}

unsigned char byte_check() // Function to check carraige return and new line character
{
switch(str[0])
{
case 0x0a:
{ // Return 0x00 for new line
return 0x00;
break ;
}
case 0x0d:
{ // Return 0x01 for carriage return
return 0x01;
break ;
}
default :return 0x02 ; // Return 0x02 for characters except new line and carriage return
}
}

void main()
{
lcd(); // Initialize LCD
init_serial(); // Initialize serial port
count=(-1);
delay(500);
lcd_data_string("Ready");
delay(10);
lcd_cmd(0x01);
IE=0x94;
transmit_data('A'); // Transmit 'A' to serial port
delay(1);
transmit_data('T'); // Transmit 'T' to serial port
delay(1);
transmit_data(0x0d); // Transmit carriage return to serial port
delay(50);
while(1)
{
if(count>=0)
{
check=byte_check(); // Check the character
if(check!=0x00)
{
if(check==0x01)
{
if(check_space==1) // Check previous character
{
lcd_data(0x20);
check_space=0;
}
}
else
{
lcd_data(str[0]);
check_space=1;
}
}
count--;
for(i=0;i<count;i++) // Shift the whole array to one left
{
str=str[i+1];
}
}
}
}

 

[jayanth.devarayanadurga]

To receive data (GSM response) you have to use Serial interrupt.

 

[Mohammed_]

Hi..
Can you help how to write it? because I don`t know Embedded C good.

thank you

 

[aameer]

Hi ..
just increase the buffer value and check
i mean.. make this
unsigned char check,str[15];
as
unsigned char check,str[65];

 

[Mohammed_]

^^^^
I`ll try. And I`ll search how include switch and make if statement. And how to define used ports?

 

[jayanth.devarayanadurga]

See 8051 UART examples at saeedsolution.blogspot.com for Serial Interrupt code. Also chexk 8051 GSM projects at engineersgarage.com

 

[Mohammed_]

O.K I`ll see then tell you what happen.