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jjacob
Joined: 08 Mar 2008
Posts: 54
Location: PORTUGAL (PORTO)
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| SMS send problems |
 Posted: Sat Aug 23, 2008 4:01 am |
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Hi,
i'm having a strange problem while sending SMS using PIC18F452.
I've searched in the FORUM but i couldn't find out my problem.
I know that for sending SMS it's just :
| Code: | printf("AT+CMGF=1); //text mode
printf("AT+CMGS="+yyyyy"); //where +yyyyy is the destination number
putc(13);
printf("SMS text message....");
putc(26); |
The strange thing is if i connect my circuit, with the above code, to Hyperterminal, i see all the text flowing.
If i connect to my modem (Siemmens TC35 or MC35i) nothing happens.
Not even the CMGF is changed. Before i connect the circuit, i force the value of CMGF to 0 (AT+CMGF=0) on the modem with Hyperterminal. In my code i force to 1, but nothing happens!!!
I also tested the connections, and i have PIN3(Tx) of DB9 to PIN8(R2in) of MAX232 and then to PIN26(Rx) of 18F452. For Rx i have PIN2(Rx) of DB9 to PIN7(T2out) of MAX232 and the to PIN25(Tx) of 18F452.
Is there any thing else that i must do ?? Or what am i doing wrong ?
Thank you...
Jacob |
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RayJones
Joined: 20 Aug 2008
Posts: 30
Location: Melbourne, Australia
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| Posted: Sat Aug 23, 2008 4:11 am |
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If you have done a copy paste onto the forum, you have several issues with quotes in your printf's.
First line is missing the closing quote, and will most likely include the printf as text to print.
The second line needs to have the number delimited using \"+yyyy\"
Finally, a \r or \n at the end of each string will make sure the modem accepts the AT command.
ie
| Code: | printf("AT+CMGF=1\r"); //text mode
printf("AT+CMGS=\"+yyyyy\"\r"); //where +yyyyy is the destination number
putc(13);
printf("SMS text message....\r");
putc(26); |
A disclaimer - I don't know the hayes commands you are using, but generally they would be the same rules on any modem.
Cheers, Ray |
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RayJones
Joined: 20 Aug 2008
Posts: 30
Location: Melbourne, Australia
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| Posted: Sat Aug 23, 2008 4:20 am |
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BTW, you can lose the puts(13).
That is identical to the printf("\r").
ie
\r is a Carriage Return = decimal 13 (^M)
\n is a Line Feed = decimal 10 (^J) |
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jjacob
Joined: 08 Mar 2008
Posts: 54
Location: PORTUGAL (PORTO)
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| Posted: Sat Aug 23, 2008 5:42 am |
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Thank you Ray for your quick answer...
The quotes, it was a BAD copy/paste SORRY...
I follow your advice about the printf.
I compiled the code and loaded to PIC.
Still don't' work 
I've reduced the code (main()) to :
| Code: | | printf("AT+CMGF=1\r"); |
I force 'AT+CMGF=0' in Hyperterminal.
I power on the PIC.
I connect the Modem to my PC and query the modem about CMGF (AT+CMGF?) and returns 0 !!!
With this 'complex' code, i think it should work...
Any suggestion ?? Anything ...
Thanks
Jacob |
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jjacob
Joined: 08 Mar 2008
Posts: 54
Location: PORTUGAL (PORTO)
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| Posted: Sat Aug 23, 2008 12:19 pm |
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My PIC is a 18F452, the clock is 20MHz and Baud Rate is 9600. Is this a problem ? Must i low the clock to 4MHz ? The PIC is to quick for the modem ?
But they are with the same baud rate ...
I really can't find out an explanation for this simple code don't work.
Thank you ...
Jacob |
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RayJones
Joined: 20 Aug 2008
Posts: 30
Location: Melbourne, Australia
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| Posted: Sat Aug 23, 2008 5:08 pm |
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Hello Jacob,
My next best suggestions are:
1/ connect your PIC project so it's serial port communicates with the PC running Hyperterminal (ugggh  ) via a NULL MODEM CONNECTION.
If your PIC talks to the PC without the NULL MODEM, that is the answer, you must cross the Tx/Rx lines from the PIC!
2/ if you can scrounge or borrow an oscilloscope and monitor the serial data lines you will see if the serial data is coming from the PIC to start with.
3/ Do you have a RS232 driver of some form between the PIC and modem, eg a MAX232 device?
The most important important thing this does is to invert the signals, the voltages are somewhat secondary, but ideally you do also want the bipolar signalling.
4/ try a delay between the AT commands, perhaps the modem is not happy if you slam commands in too quick before waiting for the OK's back....
I've done far too much serial traffic coding in the past, and it still can trap me these days. #1 problem always being the cross up of Tx/Rx data.
If you can find a better terminal program than Hyperterminal to run on the PC you will find life is much better. I've used ZOC for a long time, particualrly because it also lets you do telnet over sockets as well as the serial port business.
There are also others equally more useful than Hyperterminal, which is simply a terrible program to deal with, it tries too hard to hide the low level serial port setup. You want full control when developing. 
Cheers, Ray |
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jjacob
Joined: 08 Mar 2008
Posts: 54
Location: PORTUGAL (PORTO)
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| Posted: Sat Aug 23, 2008 7:03 pm |
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Thank you Ray ...
It's really strange this serial communication
I will follow your advices... and as soon as i have some news i will write to the forum.
Thank you once again again for your help.
Jacob |
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filjoa
Joined: 04 May 2008
Posts: 260
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| Posted: Sun Aug 24, 2008 7:44 pm |
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Hi
your mobile phone work at baud rate 9600?
in my case I use samsung sgh2400 and I use this code for send sms:
| Quote: |
#use rs232(baud=19200, parity=N, xmit=PIN_C4, rcv=PIN_C5, bits=8, stream=tlmport)
fprintf(tlmport,"at\r");
delay_ms(500);
fprintf(tlmport,"at+cmgf=1\r");
delay_ms(500);
fprintf(tlmport,"at+cmgs=\"yyyyyyyyy\"\r");
delay_ms(500);
fprintf(tlmport,"text for send");
delay_ms(500);
fprintf(tlmport,"%c",0x1A);
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and all work fine.
Attention I don't have max232, I only use one bc557 on TX line of mobile phone for up voltage for 5V TTL.
best regards |
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johanpret
Joined: 23 Oct 2006
Posts: 33
Location: South Africa
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| Posted: Mon Aug 25, 2008 1:21 am |
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When using a terminal there is a natural delay between the commands. If you issue the commands like u did then they fail. You need to wait for the response from the modem after the command was issued. You can either look at the received data from the modem and trigger the sending of the next command after receiving the response from the previous command or you can do it by using the delay between issueing commands like filjos indicated.
Hope it clear the issue.
Johan
_________________
Johan Pretorius |
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jjacob
Joined: 08 Mar 2008
Posts: 54
Location: PORTUGAL (PORTO)
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| Posted: Tue Aug 26, 2008 5:35 am |
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Hi,
thank you all for your attention
Ray, everything in your list was checked (even the new terminal... i'm using ZOC now!!).
filjoa, my modem is working 9600 and i've tested your code (changed to 9600) and didn't work.
Johan, i've tried to put delays ... but didn't work.
THIS IS VERY STRANGE.
MORE STRANGE is this :
| Code: | #use rs232(stream=tlm, baud=9600, xmit=PIN_C6, rcv=PIN_C7, parity=N, bits=8, stop=1)
fprintf(tlm,"AT+CMGF=1\r");
delay_ms(500);
fprintf(tlm,"xx");
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The above code, is as simple as it is. This is my main().
The output in 'ZOC' or in 'Hyperterminal' is :
But the cursor stands below the A. Where is the 'xxx' that i want to print ?
So i test this code :
| Code: |
#use rs232(stream=tlm, baud=9600, xmit=PIN_C6, rcv=PIN_C7, parity=N, bits=8, stop=1)
fprintf(tlm,"AT+CMGF=1\r");
delay_ms(500);
fprintf(tlm,"xx");
fprintf(tlm,"yy"); |
Now the output is :
So, my system prints the 'AT+CMGF=1' then execute the '\r' (CR) and then writes the 'xx' and leaves the cursor below '+'.
Once again, where is the 'yy' that i send it to write ?
Why it doesn't write to serial port the last line ? Is because is the last line of code ? ??? My program is just the lines above and then ends...
Any sugestion ?
Thank you for your attention.
Jacob |
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filjoa
Joined: 04 May 2008
Posts: 260
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| Posted: Tue Aug 26, 2008 12:25 pm |
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Hi
you can write there what commands you write on terminal for send an SMS?
when I put "fprintf(tlm,"AT+CMGF=1\r");" is for mobile phone send sms in text mode.
regards |
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jjacob
Joined: 08 Mar 2008
Posts: 54
Location: PORTUGAL (PORTO)
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| Posted: Tue Aug 26, 2008 12:36 pm |
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OK.
That was just a test to the PIC.
But it didn'change the status of '+CMGF' (to send SMS in text mode) and my question is : Why the last line of my code wasn't executed ?
I would like to understand this...
Can anybody explain that ?
Thank you
Jacob |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Tue Aug 26, 2008 12:45 pm |
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| Quote: |
Why it doesn't write to serial port the last line ? Is because is the last line of code ? My program is just the lines above and then ends. |
You are only posting code fragments. If you posted a complete test
program, I suspect that it would look like this:
| Code: | #include <18F452.h>
#fuses XT,NOWDT,PUT,BROWNOUT,NOLVP
#use delay(clock=4000000)
#use rs232(stream=tlm, baud=9600, xmit=PIN_C6, rcv=PIN_C7, parity=N, bits=8, stop=1)
void main()
{
fprintf(tlm,"AT+CMGF=1\r");
delay_ms(500);
fprintf(tlm,"xx");
fprintf(tlm,"yy");
} |
The reason why this program fails to print the last two characters is
because you are letting it fall off the end of main().
Compile the program. Look at the .LST file. What do you see at the
end of the file?
| Quote: | .................... fprintf(tlm,"yy");
009C: MOVLW 79
009E: BTFSS PIR1.TXIF
00A0: BRA 009E
00A2: MOVWF TXREG
00A4: MOVLW 79
00A6: BTFSS PIR1.TXIF
00A8: BRA 00A6
00AA: MOVWF TXREG
....................
.................... }
00AC: SLEEP |
The compiler inserts a SLEEP instruction at the end of main().
The hardware UART will be in the process of sending the last two
characters when it hits the SLEEP instruction. At that point, the PIC's
oscillator is shut down. The UART doesn't have an internal clock
anymore. It can't send the last two characters.
The solution is to prevent it from hitting the SLEEP instruction by
putting a continuous loop at the end of main(), as shown below.
| Quote: | void main()
{
fprintf(tlm,"AT+CMGF=1\r");
delay_ms(500);
fprintf(tlm,"xx");
fprintf(tlm,"yy");
while(1);
} |
Do this in all your programs. |
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jjacob
Joined: 08 Mar 2008
Posts: 54
Location: PORTUGAL (PORTO)
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| Posted: Tue Aug 26, 2008 3:46 pm |
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Thank you PCM programmer.
My code was exactly as you suspected 
Your explanation was perfect. Now i understand why my code was not working.
Thank you and thank you for your advice about writing code.
Jacob |
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jjacob
Joined: 08 Mar 2008
Posts: 54
Location: PORTUGAL (PORTO)
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| Posted: Tue Aug 26, 2008 4:22 pm |
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Thank you all.
Now i can send SMS using PIC
After i few adjusts in software it's working.
The only thing that i really changed in the code was the last line for sending SMS :
| Code: | | printf("%04Ld%c", data[i+12], 0x1A); |
where 'data[i+12]' is an array with the data that i want to send. It's inside a 'for' cycle.
If i print like this :
| Code: | printf("%04Ld", data[i+12]);
printf("%c",0x1A);
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It wouldn't work.
I suspect that 'printf' sends some extra code. The last thing that can me send to the modem is ^Z. If a CR or any 'strange' ascii code is send before ^Z, the SMS will not be send.
Jacob |
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