STM32F0xx_StdPeriph_Examples/SysTick/SysTick_Example/main.c

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/**
  ******************************************************************************
  * @file    SysTick/SysTick_Example/main.c 
  * @author  MCD Application Team
  * @version V1.4.0
  * @date    24-July-2014
  * @brief   Main program body
  ******************************************************************************
  * @attention
  *
  * <h2><center>&copy; COPYRIGHT 2014 STMicroelectronics</center></h2>
  *
  * Licensed under MCD-ST Liberty SW License Agreement V2, (the "License");
  * You may not use this file except in compliance with the License.
  * You may obtain a copy of the License at:
  *
  *        http://www.st.com/software_license_agreement_liberty_v2
  *
  * Unless required by applicable law or agreed to in writing, software 
  * distributed under the License is distributed on an "AS IS" BASIS, 
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  *
  ******************************************************************************
  */

/* Includes ------------------------------------------------------------------*/
#include "main.h"

/** @addtogroup STM32F0xx_StdPeriph_Examples
  * @{
  */

/** @addtogroup SysTick_Example
  * @{
  */ 

/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
/* Private macro -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
GPIO_InitTypeDef GPIO_InitStructure;
static __IO uint32_t TimingDelay;

/* Private function prototypes -----------------------------------------------*/
void Delay(__IO uint32_t nTime);

/* Private functions ---------------------------------------------------------*/

/**
  * @brief   Main program
  * @param  None
  * @retval None
  */
int main(void)
{
  /*!< At this stage the microcontroller clock setting is already configured, 
       this is done through SystemInit() function which is called from startup
       file (startup_stm32f0xx.s) before to branch to application main.
       To reconfigure the default setting of SystemInit() function, refer to
       system_stm32f0xx.c file
     */     
       
  /* Initialize Leds mounted on STM320518-EVAL board */
  STM_EVAL_LEDInit(LED1);
  STM_EVAL_LEDInit(LED2);
  STM_EVAL_LEDInit(LED3);
  STM_EVAL_LEDInit(LED4);

  /* Turn on LED1 and LED3 */
  STM_EVAL_LEDOn(LED1);
  STM_EVAL_LEDOn(LED3);

  /* Setup SysTick Timer for 1 msec interrupts.
     ------------------------------------------
    1. The SysTick_Config() function is a CMSIS function which configure:
       - The SysTick Reload register with value passed as function parameter.
       - Configure the SysTick IRQ priority to the lowest value (0x0F).
       - Reset the SysTick Counter register.
       - Configure the SysTick Counter clock source to be Core Clock Source (HCLK).
       - Enable the SysTick Interrupt.
       - Start the SysTick Counter.
    
    2. You can change the SysTick Clock source to be HCLK_Div8 by calling the
       SysTick_CLKSourceConfig(SysTick_CLKSource_HCLK_Div8) just after the
       SysTick_Config() function call. The SysTick_CLKSourceConfig() is defined
       inside the misc.c file.

    3. You can change the SysTick IRQ priority by calling the
       NVIC_SetPriority(SysTick_IRQn,...) just after the SysTick_Config() function 
       call. The NVIC_SetPriority() is defined inside the core_cm0.h file.

    4. To adjust the SysTick time base, use the following formula:
                            
         Reload Value = SysTick Counter Clock (Hz) x  Desired Time base (s)
    
       - Reload Value is the parameter to be passed for SysTick_Config() function
       - Reload Value should not exceed 0xFFFFFF
   */
  if (SysTick_Config(SystemCoreClock / 1000))
  { 
    /* Capture error */ 
    while (1);
  }

  while (1)
  {
    /* Toggle LED2 and LED4 */
    STM_EVAL_LEDToggle(LED2);
    STM_EVAL_LEDToggle(LED4);

    /* Insert 50 ms delay */
    Delay(50);

    /* Toggle LED1 and LED3 */
    STM_EVAL_LEDToggle(LED1);
    STM_EVAL_LEDToggle(LED3);

    /* Insert 100 ms delay */
    Delay(100);
  }
}

/**
  * @brief  Inserts a delay time.
  * @param  nTime: specifies the delay time length, in milliseconds.
  * @retval None
  */
void Delay(__IO uint32_t nTime)
{ 
  TimingDelay = nTime;

  while(TimingDelay != 0);
}

/**
  * @brief  Decrements the TimingDelay variable.
  * @param  None
  * @retval None
  */
void TimingDelay_Decrement(void)
{
  if (TimingDelay != 0x00)
  { 
    TimingDelay--;
  }
}

#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****/