STM32F4 Timer interrupt and Sending data over Usart

[goktug]

I am using the STM32F407VET6 and SPL libraries. My goal is very straightforward, just send data over usart periodically.

But when I send data (buttoncheck function) inside the timer interrupt it stucks " while(USART_GetFlagStatus(USART3, USART_FLAG_TC) == RESET)" while loop

I checked data status register SR its always zero.

Do you have any ideas or suggestions what to check more ?

thanks.

#include "math.h"
#include "float.h"
#include "string.h"
#include "stdio.h"
#include "stdlib.h"
#include <misc.h>
#include <stm32f4xx_usart.h>
#include <stm32f4xx_gpio.h>
#include <stm32f4xx_rcc.h>
#include <stm32f4xx_can.h>
#include <stm32f4xx_tim.h>
#include <stm32f4xx_exti.h>
#include <stm32f4xx_syscfg.h>
 
 
GPIO_InitTypeDef  GPIO_InitStructure;
 
 
void buttonCheck();
void USARTSend(char *pucBuffer);
void TIM5_IRQHandler();
 
 
 
int test=0;
 
void USARTSend(char *pucBuffer)
{
 
    while (*pucBuffer)
    {
        USART_SendData(USART3, *pucBuffer++);
 
        USART_ClearITPendingBit(USART3,USART_IT_TC);
        while(USART_GetFlagStatus(USART3, USART_FLAG_TC) == RESET)
        {
        }
 
    }
}
 
 
void TIM5_IRQHandler()
	{
	    // Checks whether the TIM5 interrupt has occurred or not
 
	if (TIM_GetITStatus(TIM5, TIM_IT_Update) != RESET)
	        {
	TIM_ClearITPendingBit(TIM5, TIM_IT_Update);
 
	buttonCheck();
 
	    }
	}
 
 
void buttonCheck(){
 
	//sprintf(Buffer2, "pi = %d \n",a);
		 USARTSend("hello\n");
}
 
int main(void)
{
	SystemInit();
 
	  	  	/*******************TIMER**********************/
		    // Enable clock for TIM5
		    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM5, ENABLE);
		    TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStruct;
		    TIM_TimeBaseInitStruct.TIM_Prescaler = 4199;
		    TIM_TimeBaseInitStruct.TIM_Period = 9999;
		    TIM_TimeBaseInitStruct.TIM_ClockDivision = TIM_CKD_DIV1;
		    TIM_TimeBaseInitStruct.TIM_CounterMode = TIM_CounterMode_Up;
		    TIM_TimeBaseInit(TIM5, &TIM_TimeBaseInitStruct);
		    TIM_ITConfig(TIM5, TIM_IT_Update, ENABLE);
		    TIM_Cmd(TIM5, ENABLE);
 
		    NVIC_InitTypeDef NVIC_InitStruct;
		    NVIC_InitStruct.NVIC_IRQChannel = TIM5_IRQn;
		    NVIC_InitStruct.NVIC_IRQChannelPreemptionPriority = 5;
		    NVIC_InitStruct.NVIC_IRQChannelSubPriority = 5;
		    NVIC_InitStruct.NVIC_IRQChannelCmd = ENABLE;
		    NVIC_Init(&NVIC_InitStruct);
 
		   /*******************TIMER**********************/
 
	        /*******************USART3**********************/
 
 
		    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOD, ENABLE);
 
			GPIO_PinAFConfig(GPIOD, GPIO_PinSource8, GPIO_AF_USART3);
			GPIO_PinAFConfig(GPIOD, GPIO_PinSource9, GPIO_AF_USART3);
 
			NVIC_InitTypeDef NVIC_InitStructure5;
 
			NVIC_InitStructure5.NVIC_IRQChannel = USART3_IRQn;
			NVIC_InitStructure5.NVIC_IRQChannelPreemptionPriority = 0;
			NVIC_InitStructure5.NVIC_IRQChannelSubPriority = 0;
			NVIC_InitStructure5.NVIC_IRQChannelCmd = ENABLE;
			NVIC_Init(&NVIC_InitStructure5);
 
			GPIO_InitTypeDef GPIO_InitStructure3;
 
			GPIO_InitStructure3.GPIO_Pin = GPIO_Pin_8 | GPIO_Pin_9; // PC.6 USART6_TX, PC.7 USART6_RX
			GPIO_InitStructure3.GPIO_Mode = GPIO_Mode_AF;
			GPIO_InitStructure3.GPIO_OType = GPIO_OType_PP;
			GPIO_InitStructure3.GPIO_PuPd = GPIO_PuPd_NOPULL;
			GPIO_InitStructure3.GPIO_Speed = GPIO_Speed_50MHz;
			GPIO_Init(GPIOD, &GPIO_InitStructure3);
 
			USART_InitTypeDef USART_InitStructure;
			RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART3, ENABLE);
		    USART_InitStructure.USART_BaudRate = 115200;
			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(USART3, &USART_InitStructure);
			USART_ITConfig(USART3, USART_IT_RXNE, ENABLE);
			USART_Cmd(USART3, ENABLE);
 
			/*******************USART3**********************/
 
 
			/* GPIOG Peripheral clock enable */
			RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOE, ENABLE);
 
			/* Configure PG6 and PG8 in output pushpull mode */
			GPIO_InitStructure.GPIO_Pin = GPIO_Pin_13 | GPIO_Pin_9;
			GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;
			GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
			GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;
			GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
			GPIO_Init(GPIOE, &GPIO_InitStructure);
 
  while (1)
  {
	  GPIOE->BSRRH = GPIO_Pin_13;
	//USARTSend("USART3 is ready.\r\n");
 
  }
}
 
#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
 
/**
  * @}
  */
 
/**
  * @}
  */
 
/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/