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Problem in receiving data from GSM

 
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pathmasugu



Joined: 21 Feb 2014
Posts: 25

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Problem in receiving data from GSM
PostPosted: Sun Mar 30, 2014 9:58 am     Reply with quote
Hi
I have problem in receiving data from gsm. I'm using sim 300 module.
I tested my gsm in hyperterminal, its working fine. But in project board i have received what command i send. Please someone help me.

Note,
before i referred gsm driver from Gabriel.

My hyperterminal output:
Code:

AT


OK

AT+CMGF=1


OK

AT+CNMI=2,1,0,0


OK



+CMTI: "SM",3

AT+CMGR=3


+CMGR: "REC UNREAD","+911111115343",,"14/03/30,21:08:18+22"

Dfbgbjf



OK

AT+CMGD=1


OK

AT+CMGD=

+CMTI: "SM",1

2


OK

AT+CMGD=3


OK

AT+CMGR=1


+CMGR: "REC UNREAD","+9111111343",,"14/03/30,21:09:15+22"

Hgththtg



OK



+CMTI: "SM",2

AT+CMGR=2


+CMGR: "REC UNREAD","+911111115343",,"14/03/30,21:10:13+22"

Fdhcvj



OK



+CMTI: "SM",3

My testing code:
Code:

#include <18F452.h>
#use delay(clock=20000000)
#Fuses HS
#use rs232(baud=9600,parity=N,xmit=PIN_C6,rcv=PIN_C7,bits=8,stream=GSM,errors)
#byte portb=0xf81
#byte trisb=0xf93
#byte porta=0xf80
#byte trisa=0xf92
#BYTE TRISC=0XF94
#include "flex_lcd.c"

#define buff 70
char gsm_rx[buff+1];
char count_wr=0;

#int_rda
void serial_rx_isr()
{
   gsm_rx[++count_wr]=getch(GSM);
}

void comm_check()
{ 
   lcd_gotoxy(1,1);
   lcd_putc("COMP CHECK");
   printf("AT");                //send command
   putchar(0x0D);
   delay_ms(2000);
}


void main()
{
   int i;
   trisb=0;
   trisa=0x01;
   TRISC=0x80;
   DELAY_MS(100);
   lcd_init();
 
   enable_interrupts(GLOBAL);
   enable_interrupts(INT_RDA);
   
   while(1)
   {
   comm_check();
   delay_ms(2000);
   
   if(count_wr>1)
   {
   lcd_gotoxy(1,2);
   for(i=0;i<8;i++)
      {   
       lcd_putc(gsm_rx[i]);
      }
   delay_ms(5000);   
   count_wr=0;
   lcd_init();
   }
   }
}

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ezflyr



Joined: 25 Oct 2010
Posts: 1019
Location: Tewksbury, MA

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PostPosted: Mon Mar 31, 2014 6:36 am     Reply with quote
Hi Pathmasugu,

I'm a bit reluctant to even get into this thread because your code has so many 'oddities', and 'inconsistencies' that it suggests you aren't studying the forum archives, or reading the documentation.....

Anyway..... First of all, are you sure, absolutely sure that your PIC is running, and running at the correct speed? Let's just say that a single Fuse (!) declaration is a bit 'suspicious'! To check, connect an LED to an unused I/O pin (with a suitable current limiting resistor), and add this code to the top of Main():

Code:

   // Here we blip the Power LED at power-up to show that the interface is working
   for ( iIndex = 0 ; iIndex < 3 ; iIndex++ )
   {
      output_high(PWR_LED);
      delay_ms(500);
      output_low(PWR_LED);
      delay_ms(500);
   }
      
   // Here we leave the Power LED ON
   output_high(PWR_LED);


Your 'PWR_LED' should turn On for 1/2 second, and Off for 1/2 second. Does it?

Why all the #byte definitions in your code? Get rid of them!

Why are you manually trying to manipulate the TRIS registers? Get rid of all that!

You are using 'getch(stream)' to fetch a character from the hardware UART. I don't use that function, so I don't know if it's OK or not, but the CCS manual defines 'fgetc(stream)' as the proper function to use. Use it!

Your buffer definition is a bit 'odd'. It will work, but it's non-standard. Also, your buffer has no 'overflow' protection, so if you exceed the allotted space then you'll start to overwrite other areas of memory. Here are some code snippets to help you with that...

Code:


#define RX_SIZE 10            // RS232 buffer for serial reception
char RxBuffer[RX_SIZE];       // RS232 serial RX buffer
int Index = 0;              // RS232 RX data IN index

   // Save the character to the receive buffer.
   RxBuffer[Index]=temp;

   // Check for buffer overflow.
   if ( Index >= (RX_SIZE - 1) )
      Index = 0;
   else
      Index++;


You should be using printf to send data to the LCD by re-directing using lcd_putc. This is a much more flexible and powerful method.

Code:

printf(lcd_putc, "COMP CHECK\n\r");


You've defined a stream, 'GSM', but you aren't using it consistently. Use this line instead:

Code:

fprintf(GSM, "AT\r");                //send command "AT" plus <CR>.


Likewise, in Main(), use printf to display received characters:

Code:

printf(lcd_putc, "Rcv. Char.: %c\n\r", gsm_rx[i]);


I haven't even addressed the design of your code, which is poor, or whether it might even work as intended, but this initial clean-up is necessary before anything else.....

John
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