[SOLVED] Problem in reading string from UART

[Mrunal Ahirrao]

Hi everyone,
I am reading a string as response from SIM 300 GSM module. The string transmitted by GSM module is "RING" so I am using UART1_Read_text library function.I am using PIC16F628A and I am able to send SMS, dial calls etc,but as a beginner in serial communication I am unable to read/ detect the RING indicator from SIM300. Any help would be highly appreciated.I am using MikroC Pro for PIC and Here is my code:

/* Testing connection with SIM300*/

sbit LED at RB4_bit;
//char receive;
char RX[]=;
//char SR[];
//unsigned short i;



void main()
{
CMCON=0x07;
TRISA=0;
TRISB=0b00000010;
LED=0;
/*output[1]=' ';
output[2]=' ';
output[3]=' ';
output[4]=' ';*/

delay_ms(60000);//delay to let SIM300 ready
UART1_Init(9600);
UART1_Write_Text("AT\r");
Delay_ms(2000);
while(1)
{
if(UART1_Data_Ready() == 1)
{

UART1_Read_Text(&RX,"\r\n",6);
}
Delay_ms(2000);
if((RX[1]=='R')&&(RX[2]=='I')&&(RX[3]=='N')&&(RX[4]=='G'))
{
UART1_Write_Text("ATH\r");
LED=~LED;
RCREG=0;    //Set receive registry to zero
}
}
}

 

[rado]

what is the format of data send from GSM?.
You had given a delimitter \r\n. Is the message send from GSM ends with the same \r\n?
also u initialized RX, but why you store the received data to &RX?

UART1_Read_Text(&RX,"\r\n",6);
this instruction will check for a data that ends with \r\n and store it in &RX.
I think that you should check for the data format send from GSM ,or make it to end with \r\n.
Also store the received data to RX

 

[milan.rajik]

Check for delimiter "OK\r\n"

 

[Mrunal Ahirrao]

what is the format of data send from GSM?.
You had given a delimitter \r\n. Is the message send from GSM ends with the same \r\n?
also u initialized RX, but why you store the received data to &RX?

UART1_Read_Text(&RX,"\r\n",6);
this instruction will check for a data that ends with \r\n and store it in &RX.
I think that you should check for the data format send from GSM ,or make it to end with \r\n.
Also store the received data to RX

Actually I don't know the GSM format for data but with much try I have succeeded in comparing two strings for equality. And I have used RX array for storing the received string UART and then comparing it with predefined string. Here is my modified code:

/* Testing connection with SIM300*/

sbit LED at RB4_bit;
//char receive;
char RX[]=;
//char SR[];
//unsigned short i;



void main()
{
CMCON=0x07;
TRISA=0;
TRISB=0b00000010;
LED=0;
/*output[1]=' ';
output[2]=' ';
output[3]=' ';
output[4]=' ';*/

delay_ms(60000);//delay to let SIM300 ready
UART1_Init(9600);
UART1_Write_Text("AT\r");
Delay_ms(2000);
while(1)
{
if(UART1_Data_Ready() == 1)
{

UART1_Read_Text(&RX,"\r\n",6);
}
Delay_ms(2000);
for(i=0;i<5;i++)  //string length is 5
{
   if(SR[i]==RX[i])    //here a[] is the string which is received through uart and x[] is predefined string
   {
      b++;        //increment b value by one
   }
}
if(b==5)
{
 b=0;
UART1_Write_Text("ATH\r");
LED=~LED;//write your output
}

Now the LED which is LED=0 before turn to LED=1 when I call, but now problem is When I again called then now it is LED=1 and should be inverted i.e LED=0; but its not working...

- - - Updated - - -

Check for delimiter "OK\r\n"

Now I am able to work with it milan but now its not working by program as I have replied to rado...

 

[Mrunal Ahirrao]

can't anybody help?

 

[betwixt]

char RX[]=; looks very suspicious to me.

What is it supposed to be declaring, a single char or an array. If it's an array what size is it supposed to be?
Try 'char *RX[] = {0};' or 'char RX[size];'

It would still be useful to look for a line terminator such as CR than actual text. What happens for example if it returns 'Error' instead of 'Ring'?

Brian.