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GSM Modem response


Moderators: Ajay, Junied , abbas1707, Arun Kumar V, pdi33, Shailesh NAYAK, ۞ TPS ۞, shyam, sashijoseph

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say2paul

Sat Aug 02 2008, 07:39AM

Registered Member #8461

Joined: Tue Jun 17 2008, 10:56AM

Posts: 123
Thanked 6 times in 6 posts

I am trying to send an SMS with Wavecom modem using the following code from 8051 uController:

CODE:

printf("AT+CMGS=\"98xxxxxxx8\"");

printf("%c", 13);

printf("This is a test msg");

printf("%c", 26);

delay();

scanf("%s", response);

delay();

LCD("Done: ");

delay();

LCD(response);

The SMS is sent successfully, but the response returned by modem is always displayed as AA on the LCD display. But the response should be OK instead as the modem returns the following response when the SMS is sent successfully:

CODE:

+CMGS: 132

OK

I tried sending the SMS from hyperterminal with modem using the same command i.e. AT+CMGS, after sending the SMS the modem returns

CODE:

+CMGS: 132

OK

Then why the same is not returned in case of 8051??

I also tried to debug by interfacing 8051 to the hyperterminal. The command sent by 8051 display successfully on hyperterminal, when I send something in response to the command from hyperterminal then the same is displayed properly on the LCD.

Then what is the problem with Wavecom modem and 8051, why the response sent by modem is not displayed properly on the LCD?

Can anyone please help me on this!

[ Edited Sat Aug 02 2008, 11:17AM ]

say2paul

Sat Aug 02 2008, 08:38AM

Registered Member #8461

Joined: Tue Jun 17 2008, 10:56AM

Posts: 123
Thanked 6 times in 6 posts

I added the following line to the code to stop echo:
printf("ATE0\r\n");

CODE:

printf("ATE0\r\n");

delay();

printf("AT+CMGS=\"98xxxxxxx8\"");

printf("%c", 13);

printf("This is a test msg");

printf("%c", 26);

delay();

scanf("%s", response);

delay();

LCD("Done: ");

delay();

LCD(response);

Now the LCD displays ">" instead of "AA"

[ Edited Sat Aug 02 2008, 11:18AM ]

say2paul

Sat Aug 02 2008, 11:25AM

Registered Member #8461

Joined: Tue Jun 17 2008, 10:56AM

Posts: 123
Thanked 6 times in 6 posts

This will eat my head for sure...

Now when I added one more scanf("%s", response); the following code is now displaying "+MSG" instead of ">"

CODE:

printf("ATE0");

printf("%c", 13);

delay();

printf("AT+CMGS=\"9872808428\"");

printf("%c", 13);

printf("This is a test msg");

printf("%c", 26);

printf("%c", 13);

scanf("%s", response);

scanf("%s", response);

delay();

LCD("Done ");

delay();

LCD(response);

But how..? I am so much confused....

Lets assume everything is going fine, but still it should return +CMGS instead of +MGS.

And in case of "EROR" is displayed instead of "ERROR".

The second character is never show and disarded...

What is happening.. can anyone help..!

sashijoseph

Sun Aug 03 2008, 08:03PM

Registered Member #5870

Joined: Mon Feb 04 2008, 06:26PM

Posts: 650
Thanked 141 times in 134 posts

Hi Paul,
I would suggest creating a custom function for serial RX/TX instead of printf/scanf.
Since printf is working OK(sms sent successfully) you could try writing a serial rx function for now.
Else try scanf with hyperterminal,just to confirm...

Let there be music........

Shailesh NAYAK

Mon Aug 04 2008, 03:31AM

Registered Member #2498

Joined: Mon Jul 23 2007, 01:20AM

Posts: 39
Thanked 9 times in 7 posts

Hi,
+GMGS: 132 is counting of messages sent from the modem, It will be last upto 255 and will start again from "0" as it complete 255. You can either ignore this and can only rely on OK.

Best Regards

Shailesh S. NAYAK

say2paul

Mon Aug 04 2008, 04:24AM

Registered Member #8461

Joined: Tue Jun 17 2008, 10:56AM

Posts: 123
Thanked 6 times in 6 posts

I understand your point but my point is that instead of +GMGS: the LCD is showing +MGS:

But if I watch output on Hyperterminal it is +GMGS:

Can anyone guide me through this!

shyam

Mon Aug 04 2008, 08:27AM

Registered Member #2984

Joined: Mon Aug 06 2007, 11:33AM

Posts: 725
Thanked 108 times in 104 posts

may be it is indeed +CMGS instead of +MGS

and may be it sends OK instead of AA

what i mean is I will prefer that portion os the code when u are displaying the scanned response!