万利开发板STM3210B之GPIO

 GPIO.rar   

/******************** (C) COPYRIGHT 2008 STMicroelectronics ********************
* File Name          : main.c
* Author             : MCD Application Team
* Version            : V2.0.3
* Date               : 09/22/2008
* Description        : Main program body.
*******************************************************************************/
#include "stm32f10x_lib.h"


ErrorStatus HSEStartUpStatus;

void RCC_Configuration(void);
void GPIO_Configuration(void);
void Delay(vu32 nCount);

int main(void)
{

  /* System Clocks Configuration **********************************************/
  RCC_Configuration();

  /* Configure GPIOC PORT ***************************************************/
  GPIO_Configuration();

 while (1)
  {
    /* Turn on LED1 */
    GPIO_SetBits(GPIOC, GPIO_Pin_7);
    /* Insert delay */
    Delay(0xAFFFF);

    /* Turn on LED2 and LED3 */
    GPIO_SetBits(GPIOC, GPIO_Pin_6 | GPIO_Pin_5);
    /* Turn off LED1 */
    GPIO_ResetBits(GPIOC, GPIO_Pin_7);
    /* Insert delay */
    Delay(0xAFFFF);

    /* Turn on LED4 */
    GPIO_SetBits(GPIOC, GPIO_Pin_4);
    /* Turn off LED2 and LED3 */
   GPIO_ResetBits(GPIOC, GPIO_Pin_6| GPIO_Pin_5);
    /* Insert delay */
    Delay(0xAFFFF);

    /* Turn off LED4 */
    GPIO_ResetBits(GPIOC, GPIO_Pin_4);
  }
}

/*******************************************************************************
* Function Name  : RCC_Configuration
* Description    : Configures the different system clocks.
* Input          : None
* Output         : None
* Return         : None
*******************************************************************************/
void RCC_Configuration(void)
{
  /* 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/2 */
    RCC_PCLK1Config(RCC_HCLK_Div2);

    /* 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)
    {
    }
  }
}


/*******************************************************************************
* Function Name  : GPIO_Configuration
* Description    : Configures GPIOC PORT.
* Input          : None
* Output         : None
* Return         : None
*******************************************************************************/
 void GPIO_Configuration(void)
 {
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC, ENABLE);

  GPIO_InitTypeDef GPIO_InitStructure;

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_7 | GPIO_Pin_6 | GPIO_Pin_5 | GPIO_Pin_4;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_Init(GPIOC, &GPIO_InitStructure);
 }
/*******************************************************************************
* Function Name  : Delay
* Description    : Inserts a delay time.
* Input          : nCount: specifies the delay time length.
* Output         : None
* Return         : None
*******************************************************************************/
void Delay(vu32 nCount)
{
  for(; nCount != 0; nCount--);
}
/******************* (C) COPYRIGHT 2008 STMicroelectronics *****END OF FILE****/

   这个例程很简单，但是延时函数的延时不怎么精确，基本延时=1/72us，修正后将其精确基本延时1ms,用SysTick来实现。

/*******************************************************************************
* Function Name  : SysTick_Configuration
* Description    : Configures the SysTick to generate an interrupt each 1 millisecond.
* Input          : None
* Output         : None
* Return         : None
*******************************************************************************/
void SysTick_Configuration(void)
{
  /* Select AHB clock(HCLK) as SysTick clock source */
  SysTick_CLKSourceConfig(SysTick_CLKSource_HCLK);

  /* Set SysTick Priority to 3 */
  NVIC_SystemHandlerPriorityConfig(SystemHandler_SysTick, 3, 0);

  /* SysTick interrupt each 1ms with HCLK equal to 72MHz */
  SysTick_SetReload(72000);

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

/*******************************************************************************
* Function Name  : Delay
* Description    : Inserts a delay time.
* Input          : nTime: specifies the delay time length, in milliseconds.
* Output         : None
* Return         : None
*******************************************************************************/
void Delay(u32 nTime)
{
/* Enable the SysTick Counter */
SysTick_CounterCmd(SysTick_Counter_Enable);

TimingDelay = nTime;

while(TimingDelay != 0);

/* Disable the SysTick Counter 经测试可以不要*/
SysTick_CounterCmd(SysTick_Counter_Disable);
/* Clear the SysTick Counter 经测试可以不要*/
SysTick_CounterCmd(SysTick_Counter_Clear);
}

中断处理程序

/*******************************************************************************
* Function Name  : SysTickHandler
* Description    : This function handles SysTick Handler.
* Input          : None
* Output         : None
* Return         : None
*******************************************************************************/
void SysTickHandler(void)
{
TimingDelay--;
}

 GPIO_SysTick.rar   

系统时钟定时器的周期与驱动的时钟频率和Reload值相关。

RCC通过AHB时钟(HCLK)8分频后作为Cortex系统定时器(SysTick)的外部时钟(这是默认的)。

驱动系统时钟定时器的时钟源有两个：HCLK或(HCLK/8默认)，通过调用SysTick_CLKSourceConfig(SysTick_CLKSource_HCLK)或SysTick_CLKSourceConfig(SysTick_CLKSource_HCLK_Div8)选择。再用HCLK的时候需要写调用函数SysTick_CLKSourceConfig(SysTick_CLKSource_HCLK)，而(HCLK/8默认)不用。

/* SysTick end of count event each 1ms with input clock equal to 9MHz (HCLK/8, default) */
SysTick_SetReload(9000);

/* Enable SysTick interrupt */
SysTick_ITConfig(ENABLE);