Strange behaviour with USART interrupt - STM32F3discovery

[andreaspiezia9]

Posted on January 16, 2014 at 20:08

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_TXGPIO_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>

[andreaspiezia9]

Posted on January 16, 2014 at 20:11

Here below the output with line uncommented:

<code>This is an echo test for USART interruptp //character from keyboardIn fullu //character from keyboardIn fully //character from keyboardIn full </code>