send sms with sim900 on stm32f107

A slightly more clueful approach, but still ignoring the responses from the modem might look like this.

/* Includes */
#include ''stm32f10x.h''
#include ''stm32f10x_gpio.h''
#include ''misc.h''
#define CR 13
#define LF 10
void RCC_Configuration(void);
void GPIO_Configuration(void);
void sendMessage(*header, char *message);
void Delay(__IO uint32_t nCount);
int main(void)
{
USART_InitTypeDef USART_InitStructure;
char SendMessageTO[] = ''AT+CMGS=\''+3473802890\''''; // Not goofy angle quotes
char SendMessageMESSAGE[] = ''THIS IS A SAMPLE MESSAGE'';
/* System Clocks Configuration */
RCC_Configuration();
/* Configure the GPIO ports */
GPIO_Configuration();
/* USARTx configuration ------------------------------------------------------*/
/* USARTx configured as follow:
- BaudRate = 9600 baud
- Word Length = 8 Bits
- Two Stop Bit
- Odd parity
- Hardware flow control disabled (RTS and CTS signals)
- Receive and transmit enabled
*/
USART_InitStructure.USART_BaudRate = 9600;
USART_InitStructure.USART_WordLength = USART_WordLength_8b;
USART_InitStructure.USART_StopBits = USART_StopBits_1;
USART_InitStructure.USART_Parity = USART_Parity_No;
USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
USART_Init( USART1,&USART_InitStructure);
sendMessage(SendMessageTO, SendMessageMESSAGE);
while(1)
{
}
}
void RCC_Configuration(void)
{
/* Enable GPIO clock */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
/* Enable USART2 Clock */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE);
}
void GPIO_Configuration(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
/* Configure USART1 Rx as input floating */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
GPIO_Init(GPIOA,&GPIO_InitStructure);
/* Configure USART1 Tx as alternate function push-pull */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_Init(GPIOA,&GPIO_InitStructure);
} 
void USART1_OutChar(char ch)
{
while(USART_GetFlagStatus(USART1, USART_FLAG_TXE) == RESET); // Wait for the TX buffer to be EMPTY FFS
USART_SendData(USART1, ch);
}
void USART1_OutString(char *s)
{
while(*s)
USART1_OutChar(*s++);
}
void sendMessage(char *header, char *message)
{
USART1_OutString(header);
USART1_OutString(''

'');
Delay(1000); // Should really wait for '>' or ERROR response from modem
USART1_OutString(message);
USART1_OutString(''

'');
USART1_OutChar(0x1A); // ^Z Termination of SMS
}
void Delay(__IO uint32_t nCount) //in millisecond
{
nCount = nCount * 5940 *2;//381;
while(nCount--)
{
}
}

thank you for your support but there is something that is going wrong. When i run the program it stuscks somewhere and in the console I get this message looping forever: ''No trace recived from target''

Are you expecting everyone to know what a sim900 is?

The program sends the first A from the header ''AT+CMGS=\''+3473802890\'''' , than it stucks on this instruction when it has to send T

After

Thanks, the program executes all the instructions but the sms is still not send. How can I investigate on what is happening? When I use rfid I write a command and then I read the interface i2c to see if there is a problem. Here  can I do something similar?

You'd perhaps want to talk to the modem, check other aspects are working. It will respond to commands with OK/ERROR, etc. You'd want to read the AT command spec for the modem and understand it.

I think I am talking with the modem, but his response is not what I expect. Not OK or ERROR but some rubbish char. What's going wrong?

No idea, I don't have your board(s), schematics, or data sheets. Provide or cite if you expect to receive useful advice.

Hi