Problem in GSM modem response handling using interrupt method of LPC2148 UART0

You really do not like to use the proper tags for source code...

Notice the difference with source code posted using the intended tags?

#include <stdio>

int main(void) {
    printf("Hello World!\n");
    return 0;
}

By the way - you shouldn't read twice from U0IIR since reading from registers isn't identical to reading from normal RAM - that's why you have the "regVal" variable.

You really do not like to use the proper tags for source code...

Notice the difference with source code posted using the intended tags?

#include <stdio>

int main(void) {
    printf("Hello World!\n");
    return 0;
}

By the way - you shouldn't read twice from U0IIR since reading from registers isn't identical to reading from normal RAM - that's why you have the "regVal" variable.

Thanks for your reply sir,

Actually i seen in a tutorial in that code for timer0 before to check overflow in isr,they read the register by a variable.That's why i used that variable(regval).But sir,i removed that variable and checked ,i am getting the same problem.If you allow me i will update here my main() code.

Have you read the chapter about UART0 in the processor user manual? You don't seem to check if the least significant bit of U0IIR is zero. And it's good to care about both RDA and CTI since both are enabled by the same bit in U0IER.

And you should read U0IIR at the end of your initialization routine.

Sir, I read the processor manual for UART0,I didn't check the CTI as well the 0'th bit of U0IIR. When Gsm getting incoming message means with in that fraction it will send the full string in to Rx buffer as well i don't know where & how to check these things in the isr function and one more thing is that if i connecting lke RFID reader,gps modules means i can able to receive and read the full string without any problem.Then how it could be possible sir?

By the way - I think you should consider looking at the ring buffer implementation that Keil has available. It's way better than copying a full text line when you see a line break - you don't want big loops inside an ISR.

Sir, ring buffer..? i have no prevoius experiance with ring buffer.So i have to google about ring buffer and also why & where do you refer me this ring buffer to implent?

To check buffer register,

"if(dataa!=0x0A)"

or

for(i=0; s1[i]!='\0';i++)

{

s2[i]=s1[i];

}
Please clarify me also I am the new one to keil.So please guide me to do the ring buffer implementation

Sorry, can't afford the time to guide you. But Google is your friend. There is more than enough information available. Just make sure to read a bit more carefully than you read the posting instructions for source code - details tends to be important.

Sorry for the mistakes in last post.I try to re write the code using ring buffer sir.Could i able to use this ring buffer concept in to ISR.?Is that possible

Most definitely - as clearly described in quite a number of articles about the use of ring buffers. They are so popular just because they work well with interrupts or with multiple threads. So you haven't located the Keil LPC2100 UART sample code yet?