pic to gsm modem

[gorilla135]

iam having a problem communicating a PIC 16f877 with a gsm modem, the problem is that the modem only works with 115200 baud rate, the code works perfectly when i connect the modem via hyperterminal but when i connect it to the PIC which has a lower baud rate it wont work. can anyone help please. thanks

[ckielstra]

Have you tried setting the modem to a lower baud rate?

AT+IPR=9600
and then make this change permanent with:
AT&w

[Mark]

Post your PIC code. I find it hard to believe that the modem will not talk slower than that!

[gorilla135]

#include <16F877.h> /* Defines chip */
#include <stdio.h> /* this gets the printf() definition */
#use delay(clock=4000000)
#fuses hs, noprotect, nowdt, nolvp
#use rs232(baud=9600,xmit=PIN_C6, rcv=PIN_C7, stream=GSM, ERRORS)


const int CR=0x0d;

void main()

{
fprintf(GSM,"AT\r\n"); /* checks are they communicating */
fprintf(GSM,"AT+CMGF=1\r\n"); /* sends an at command reay to send */
fputc(CR,GSM);
delay_ms(1000); /*sends a carriage return */
fprintf(GSM,"AT+CMGS=\"07749960685\""); /* sents the following text to this number */
fprintf(GSM,"\r\n"); /* cariage */
fputc(CR,GSM);

delay_ms(1000);
fprintf(GSM,"Hi world\r\n"); /* the text that will actually be sent */

/* sends CTRL Z */
delay_ms(1000);
fprintf(GSM,"\r\n");
fputc(0x1A,GSM); /* sends carriage return */
}

[Mark]

You aren't waiting for the responses back from the modem.

[gorilla135]

do i just put in a few delays or what,

[Mark]

Do you read any other posts? Here's one that's current right now.

http://www.ccsinfo.com/forum/viewtopic.php?t=26427

[gorilla135]

been searching for a day or two now. i just want the pic to send a text message at the minute then when i get that to work i want it to read a text message in and using the string compare function carry out a few operations if the command is correct,