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Strange behaviour with USART interrupt - STM32F3discovery

Question asked by spiezia.andrea on Jan 16, 2014
Latest reply on Jan 16, 2014 by spiezia.andrea
Hi all,
the following code works fine if I comment the line 131: OutString("In full\n");
But it doesn't give the echo character if a don't comment the line.
I don't understand why.
Your help is much appreciate.
<code>
/* Includes ------------------------------------------------------------------*/
#include "main.h"
#include <string.h> // memcpy()
  /*!< At this stage the microcontroller clock setting is already configured, 
       this is done through SystemInit() function which is called from startup
       file (startup_stm32f30x.s) before to branch to application main.
       To reconfigure the default setting of SystemInit() function, refer to
       system_stm32f30x.c file
     */ 


  
// STM32 USART2 LOOP (Tx PA.2, Rx PA.3) STM32F3xx - sourcer32@gmail.com
 
#include "stm32f30x.h"


volatile char StringLoop[] = "Conta\r\n";
volatile int full = 0;
volatile uint16_t ch;
 
/**************************************************************************************/
 
void RCC_Configuration(void)
{
  /* Enable GPIO clock */
  RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA, ENABLE);
 
  /* Enable USART clock */
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE);
}
 
/**************************************************************************************/
 
void GPIO_Configuration(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
/*-------------------------- GPIO Configuration ----------------------------*/
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2 | GPIO_Pin_3;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOA, &GPIO_InitStructure);




/* Connect USART pins to AF */
  
/* Configure Alternate Function pin muxing fabric to escape USART2 Rx and Tx */
GPIO_PinAFConfig(GPIOA, GPIO_PinSource2, GPIO_AF_7); //USART2_TX
GPIO_PinAFConfig(GPIOA, GPIO_PinSource3, GPIO_AF_7); //USART2_RX
}
 
/**************************************************************************************/
 
void USART2_Configuration(void)
{
USART_InitTypeDef USART_InitStructure;
/* USARTx configuration ------------------------------------------------------*/
/* USARTx configured as follow:
        - BaudRate = 4800 baud
        - Word Length = 8 Bits
        - One Stop Bit
        - No parity
        - Hardware flow control disabled (RTS and CTS signals)
        - Receive and transmit enabled
  */
USART_InitStructure.USART_BaudRate = 4800;
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(USART2, &USART_InitStructure);
USART_Cmd(USART2, ENABLE);
USART_ITConfig(USART2, USART_IT_RXNE, ENABLE); // Enable USART2 Receive Interrupt
     
}
 
/**************************************************************************************/
  
void NVIC_Configuration(void)
{
  NVIC_InitTypeDef NVIC_InitStructure;
  
  /* Configure the NVIC Preemption Priority Bits */
  NVIC_PriorityGroupConfig(NVIC_PriorityGroup_0);
  
  /* Enable the USART3 Interrupt */
  NVIC_InitStructure.NVIC_IRQChannel = USART2_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);
}
  
/**************************************************************************************/
 void OutString(char *s)
{
    while(*s)
    {
      while(USART_GetFlagStatus(USART2, USART_FLAG_TXE) == RESET); // Wait for Empty
 
    USART_SendData(USART2, *s++);
    }
}


/**************************************************************************************/
  
void USART2_IRQHandler(void)
{
     
    while(USART_GetFlagStatus(USART2, USART_FLAG_RXNE) == RESET); // Wait for Char
    ch  = USART_ReceiveData(USART2); // Collect Char7
          full = 1;
     
}
 
/**************************************************************************************/


int main(void)
{
     RCC_Configuration();
  GPIO_Configuration();
  NVIC_Configuration();
  USART2_Configuration();
     OutString("This is an echo test for USART interrupt\n");
     while(1)
     {
          
          if(full)
          {
          OutString("In full\n");
          while(USART_GetFlagStatus(USART2, USART_FLAG_TXE) == RESET); // Wait for Empty
          USART_SendData(USART2, ch); // Echo Char
          full = 0;
          }
     }
     
}
 
/**************************************************************************************/
 
#ifdef  USE_FULL_ASSERT
 
/**
  * @brief  Reports the name of the source file and the source line number
  *         where the assert_param error has occurred.
  * @param  file: pointer to the source file name
  * @param  line: assert_param error line source number
  * @retval None
  */
void assert_failed(uint8_t* file, uint32_t line)
{
  /* User can add his own implementation to report the file name and line number,
     ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
 
  /* Infinite loop */
  while (1)
  {
  }
}
#endif
<\code>



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