[AVR] sending and receiving sms with sim900 and avr

[mohammad.habibi]

hello all
I am new to this forum and this is my first post
I am using Sim900 for sending and receiving SMS with avr microcontroller atmega16
i programm this code thats write with codvision compilar
but this doesnt work :bang:
i dont know where is wrong,can u help me?
tnx all

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Code C - [expand]
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/*****************************************************
AVR Core Clock frequency: 11.059200 MHz
*****************************************************/
#include <mega16a.h>
#include <alcd.h>
#include <stdio.h>
#include <delay.h>
char at_cmgs[]={'A','T','+','C','M','G','S','=','"','0','9','1','1','8','5','3','0','9','6','1','"','\n'};
#define ctrl_z 0x1a
void main(void)
{
PORTC=0x00;
DDRC=0xFF;
PORTD=0x00;
DDRD=0x02;
// USART initialization
// Communication Parameters: 8 Data, 1 Stop, No Parity
// USART Receiver: On
// USART Transmitter: On
// USART Mode: Asynchronous
// USART Baud Rate: 9600
UCSRA=0x00;
UCSRB=0x18;
UCSRC=0x86;
UBRRH=0x00;
UBRRL=0x47;
// Alphanumeric LCD initialization
// Connections are specified in the
// Project|Configure|C Compiler|Libraries|Alphanumeric LCD menu:
// RS - PORTC Bit 0
// RD - PORTC Bit 1
// EN - PORTC Bit 2
// D4 - PORTC Bit 4
// D5 - PORTC Bit 5
// D6 - PORTC Bit 6
// D7 - PORTC Bit 7
lcd_init(16);
while (1)
      {
       delay_ms(2000);
       puts("AT");
       delay_ms(2000);
       puts("AT");
       delay_ms(2000);
       puts("AT");
       delay_ms(4000);
       puts("ATE0");
       delay_ms(4000);
       puts("AT+CMGF=1");
       delay_ms(4000);
       puts(at_cmgs);
       delay_ms(1000);
       puts("this is test");
       delay_ms(1000);
       putchar(ctrl_z);
       lcd_clear();
       lcd_gotoxy(0,0);
       lcd_puts("message sent");
       }
}

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[ud23]

what is your observation about output?.Do test gsm module with hyper terminal first and check the avr and GSM RX,TX connections.

 

[mohammad.habibi]

i see the output in lcd
i try to use hyper terminal with ft232rl but my ft232 dont work my schematic of ft is here
https://obrazki.elektroda.pl/8929117900_1428578608.png
and i change the ft and again doesnt worked

 

[ud23]

make sure your RX,TX are cross connected between AVR and ft232rl,I mean connect your AVR Tx--->ft232rlRx and AVR Rx--->ft232rl Tx.


https://electronics-diy.com/FT232RL_USB_to_Serial_Adapter_for_PIC_AVR_ATMEGA_ARDUINO_MCUs.php

 

[mohammad.habibi]

tnx for your helping
i connect the sim900 to pc with ft232 as you said and with hyper terminal first just i could get thise strings

RDY
CPUN: 1
CPIN: READY
CALL READY

but when in hyper terminal i want to send at command to sim900, doesnt sent any thing or sim900 doesnt sent anything...

 

[ud23]

make sure the baud rate setting are common for hyper terminal and gsm and one more thing don't forget to send '/r' for each AT commands.for example first send AT then press enter('/r') if gsm respond with OK then its working fine.

https://www.pololu.com/file/download/dronecell-getting-started.pdf?file_id=0J389

see above link for just your reference.

 

[milan.rajik]

You should send CRLF after each command like "AT\r\n" or you can also send "AT\r" a delay of 1 sec and next command.

 

[mohammad.habibi]

yes thats right
when i connect sim900 to atmega16 and sent CRLF(CRLF means enter) after each command,the sms sent
my code is here

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Code C - [expand]
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printf("AT");
      putchar(enter);
      delay_ms(1500);
      printf("AT");
      putchar(enter);
      delay_ms(1500);
      printf("AT");
      putchar(enter);
      delay_ms(1500);
      printf("AT+CMGF=1");
      putchar(enter);
      delay_ms(1500);
      printf("AT+CMGS=\"09118530961\"");
      putchar(enter);
      delay_ms(1500);
      printf ("SMS SEND TEST ");
      putchar(ctrl_z);

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enter is 0x0d and ctrl_z is 0x1a
now i want to try recieve the sms
tnx for your helping

 

[milan.rajik]

This is all you need.

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Code C - [expand]
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printf("AT\r\n");
      delay_ms(1000);
      printf("AT+CMGF=1\r\n");
      delay_ms(1000);
      printf("AT+CMGS=\"09118530961\"\r\n");
      delay_ms(2000);
      printf ("SMS SEND TEST ");
      putchar(ctrl_z);

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[mohammad.habibi]

tnx milan.rajik
my problem solved tnx