setclock.c

STM32 USART1 2 3三串口收发

#include <stm32f10x_lib.h>              /* STM32F10x Library Definitions      */
void SetupClock (void)	;
void  SysTick_Configuration(void);
 


 void SetupClock (void){

 ErrorStatus HSEStartUpStatus;
   /* RCC system reset(for debug purpose) */
  RCC_DeInit();

  /* Enable HSE */
  RCC_HSEConfig(RCC_HSE_ON);

  /* Wait till HSE is ready */
  HSEStartUpStatus = RCC_WaitForHSEStartUp();

  if (HSEStartUpStatus == SUCCESS)
  {
    /* Enable Prefetch Buffer */
    FLASH_PrefetchBufferCmd(FLASH_PrefetchBuffer_Enable);

    /* Flash 2 wait state */
    FLASH_SetLatency(FLASH_Latency_2);

    /* HCLK = SYSCLK */
    RCC_HCLKConfig(RCC_SYSCLK_Div1);

    /* PCLK2 = HCLK */
    RCC_PCLK2Config(RCC_HCLK_Div1);

    /* PCLK1 = HCLK/4 */
    RCC_PCLK1Config(RCC_HCLK_Div2);
    /* ADCCLK = PCLK2/4  */
    RCC_ADCCLKConfig (RCC_PCLK2_Div4);   

    /* PLLCLK = 8MHz * 9 = 72 MHz */
    RCC_PLLConfig(RCC_PLLSource_HSE_Div1, RCC_PLLMul_9);

    /* Enable PLL */
    RCC_PLLCmd(ENABLE);

    /* Wait till PLL is ready */
    while (RCC_GetFlagStatus(RCC_FLAG_PLLRDY) == RESET)
    {}

    /* Select PLL as system clock source */
    RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK);

    /* Wait till PLL is used as system clock source */
    while (RCC_GetSYSCLKSource() != 0x08)
    {}
  }



  /* GPIOC clock enable */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1|RCC_APB2Periph_GPIOF, ENABLE);
 
  
}	//

/*******************************************************************************
* Function Name  : SysTick_Configuration
* Description    : Configures SysTick to generate an interrupt each 250ms.
* Input          : None
* Output         : None
* Return         : None
*******************************************************************************/
void SysTick_Configuration(void)
{
  /* Select HCLK/8 as SysTick clock source */
 SysTick_CLKSourceConfig(SysTick_CLKSource_HCLK_Div8);
  
  /* SysTick interrupt each 9M(90000Hz)/45000=0.2Hz=5ms with counter clock equal to 200Hz=100Hz 翻转 frequency */
  SysTick_SetReload(90000);

  /* Enable the SysTick Counter */
  SysTick_CounterCmd(SysTick_Counter_Enable);

  /* Enable the SysTick Interrupt */
  SysTick_ITConfig(ENABLE); 
}