[SOLVED] GSM module interfacing problem to AVR

[Briez]

Hello,


I want to interface GSM module with atmega32.

I have wrote a c code using avr studio 4 and compiler winavr using 16MHZ crystal.

But when i send sms sending AT command, GSM module doesnt send sms.

I have checked my gsm module in hyperterminal. It is an okay.

I am sending commands as follow,

AT\r 
delay(1000); //millisecond 
ATE0\r 
delay(1000); //millisecond 
AT+CMGF=1\r 
delay(1000); //millisecond 
AT+CMGS="xxxxxxxxxx"\r 
delay(100); //millisecond 
(Message) 
Ctrl+Z

when i transmit "AT" to GSM it responds me with "PU".

What will be the problem?

 

[jayanth.devarayanadurga]

Mention the functions used to send character and string to USART.

This code is for 8 MHz clock. delay is causing the problem. If you use 16 MHz clock then double the delays. The delays are not giving exact milliseconds.

---

Code C - [expand]
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send_string("AT+CMGF=1");
send_data(0x0D);
send_data(0x0A);
_delay_ms(2000);
send_string("AT+CMGS=");
send_data(0x22);
send_string("974245XXXX");
_delay_ms(200);
send_data(0x22);
send_data(0x0D);
send_data(0x0A);
_delay_ms(500);
send_string("Hello from Jayanth");
send_data(0x0D);
_delay_ms(5000);
send_data(26);
send_data(0x0D);
_delay_ms(8000);

---

 

[Briez]

if i send AT+CMGR=1 some garbage data display on LCD.

My code is,

#define F_CPU 16000000UL

#include<avr/io.h>
#include<avr/interrupt.h>
#include <util/delay.h>
#include"LCD.h"

#define BAUD 9600
#define MYUBRR ((( F_CPU / ( BAUD * 16UL))) - 1)

#define rx_on	UCSRB|=(1<<RXCIE);
#define rx_off	UCSRB&=~(1<<RXCIE);

void uart_init(unsigned int ubrr);
void send_string(unsigned char *str);
void send_data(unsigned char back);
void reset_flush(void);

unsigned char ReceivedByte[200];
unsigned char count,i=0,j,k,data,AT_ack=1;


int main(void)
{

DDRB=0xFF;
DDRA=0xFF;
DDRC=0xFF;
DDRD=0xFE;


PORTD=0x00;

MCUCSR|=(1<<JTD);
MCUCSR|=(1<<JTD);

lcd_init();	

uart_init(MYUBRR);

_delay_ms(500);

lcd_send_R1(0,"GSM_init");

sei();
_delay_ms(50);
rx_off;
_delay_ms(500);


while(1)

  {
/*******************************************************************************/
//								AT+CMGR=1									//
/*******************************************************************************/
	send_string("AT+CMGR=1");				//send "AT" to GSM
	send_data(0x0D);
	send_data(0x0A);
	rx_on;							// checking response from GSM
	_delay_ms(10000);
	rx_off;	

	for(k=0;k<16;k++)
	  {
	  	lcd_cmd(0x80+k);
		lcd_data1(ReceivedByte[k]);
		_delay_ms(500);
	  }

	for(k=16;k<32;k++)
	  {
	 	k=k-16;
		lcd_cmd(0xC0+k);
		lcd_data1(ReceivedByte[k]);
		_delay_ms(500);
	  }

	for(k=32;k<48;k++)
	  {
	 	k=k-32;
		lcd_cmd(0x80+k);
		lcd_data1(ReceivedByte[k]);
		_delay_ms(500);
	  }



	reset_flush();
	_delay_ms(5000);

/*******************************************************************************/


  }

return 0;

}

/*******************************************************************************/
//							UART Initialization									//
/*******************************************************************************/
void uart_init(unsigned int ubrr)
{

UBRRH = (uint16_t)(ubrr>>8);
UBRRL = (uint16_t)ubrr;

UCSRB = (1<<RXEN)|(1<<TXEN)|(1<<RXCIE);

UCSRC = (1<<URSEL)|(3<<UCSZ0);
}

/*******************************************************************************/
//									char send to UART							//
/*******************************************************************************/

void send_data(unsigned char back)
{
  
  while( !( UCSRA & (1<<UDRE)) ) ;

    UDR=back;
}

/*******************************************************************************/
//									String send to UART							//
/*******************************************************************************/

void send_string(unsigned char *str)
{

	while(*str)
	  {
         send_data(*str++);
	  }
}

/*******************************************************************************/
//									Reset Buffer								//
/*******************************************************************************/
void reset_flush(void)
{
  i=0;
  count=0;
  for(j=0;j<200;j++)
    {
		ReceivedByte[j]='\0';
    }
}

ISR ( USART_RXC_vect )
{

	count=UDR;

if(count!=0x0D && count!=0x0A && count!='>' && count!='"')					//Do not Print \r\n and ">"
  {
	ReceivedByte[i]=count;
	i++;
  }

if(i==200)
  {
   i=0;
  }
}

Where i am making mistake?