要测一个输入方波的频率，但是时钟频率好像没有经过分频，测出的数据都是72M时钟的。
而且计数上限跟TIM_BaseInitStructure.TIM_Prescaler 设置的值有关。
具体程序如下，望高手帮忙看看。
/*******************************************************************************
* File Name : main.c
* Author : Wuhan R&D Center, Embest
* Date First Issued : 08/08/2008
* Description : Main program body
********************************************************************************/
/* Includes ------------------------------------------------------------------*/
#include "stm32f10x_lib.h"
/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
/* Private macro -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
#define ADC1_DR_Address ((u32)0x4001244C)
unsigned short int ADC_ConvertedValue;
GPIO_InitTypeDef GPIO_InitStructure;
ADC_InitTypeDef ADC_InitStructure;
DMA_InitTypeDef DMA_InitStructure;
EXTI_InitTypeDef EXTI_InitStructure;
ErrorStatus HSEStartUpStatus;
extern vu32 TimingDelay;
int aa=0;
u16 IC2Value[10] = {0};
/* Private function prototypes -----------------------------------------------*/
void RCC_Configuration(void);
void NVIC_Configuration(void);
void tim2_config(void); //定义TIM初始化函数
void GPIO_Configuration(void);
void Delay(vu32 nTime);
void SysTick_Configuration(void);
void SetupLED (void) ;
void TIM2_IRQHandler(void);
extern void SetupADC (void);
/* Private functions ---------------------------------------------------------*/
/*******************************************************************************
* Function Name : main
* Description : Main program.
* Input : None
* Output : None
* Return : None
*******************************************************************************/
int main(void)
{
#ifdef DEBUG
debug();
#endif
/* Configure the system clocks */
RCC_Configuration();
SysTick_Configuration();
/* NVIC Configuration */
tim2_config(); //定时器2配置
NVIC_Configuration();
/* Configure the GPIO ports */
GPIO_Configuration();
/* Connect EXTI Line9 to PB.9 */
//GPIO_EXTILineConfig(GPIO_PortSourceGPIOB, GPIO_PinSource8);
/* Configure EXTI Line9 to generate an interrupt on falling edge */
//EXTI_InitStructure.EXTI_Line = EXTI_Line8;
//EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
//EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Falling;
//EXTI_InitStructure.EXTI_LineCmd = ENABLE;
//EXTI_Init(&EXTI_InitStructure);
for(;;)
{
//GPIOB->ODR = 0xfffffc4f;
GPIOB->BSRR = GPIO_Pin_9;
Delay(100);
GPIOB->BRR = GPIO_Pin_9;
Delay(100);
//aa++;
//GPIOB->ODR = 0xfffffc8f;
//Delay(800);
//GPIOB->ODR = 0xfffffd0f;
//Delay(800);
//GPIOB->ODR = 0xfffffe0f;
//Delay(800);
}
}
/*******************************************************************************
* 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 : 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)
{
/* HCLK = SYSCLK */
RCC_HCLKConfig(RCC_SYSCLK_Div1);
/* PCLK2 = HCLK */
RCC_PCLK2Config(RCC_HCLK_Div1);
/* PCLK1 = HCLK/2 */
RCC_PCLK1Config(RCC_HCLK_Div2);
/* Flash 2 wait state */
FLASH_SetLatency(FLASH_Latency_2);
/* Enable Prefetch Buffer */
FLASH_PrefetchBufferCmd(FLASH_PrefetchBuffer_Enable);
/* 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)
{
}
}
/* Enable GPIOB, GPIOC and AFIO clocks */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB | RCC_APB2Periph_GPIOC |
RCC_APB2Periph_AFIO, ENABLE);
}
void tim2_config(void)
{
TIM_TimeBaseInitTypeDef TIM_BaseInitStructure;//定时器初始化结构
TIM_ICInitTypeDef TIM_ICInitStructure;
TIM_DeInit(TIM2);
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2,ENABLE);
TIM_BaseInitStructure.TIM_Prescaler = 999; //分频系数
TIM_BaseInitStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_BaseInitStructure.TIM_Period = 0xFFFF; //计数频率
TIM_BaseInitStructure.TIM_ClockDivision = 0;
TIM_TimeBaseInit(TIM2, &TIM_BaseInitStructure); //时钟基本初始化
//TIM_PrescalerConfig(TIM2, 4, TIM_PSCReloadMode_Immediate);
//TIM_ICInitStructure.TIM_ICMode = 2; //配置为输入捕获模式
TIM_ICInitStructure.TIM_Channel = TIM_Channel_2; //通道选择
TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising; //捕获上升沿
TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI;//管脚与寄存器对应关系
TIM_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1; //分频
TIM_ICInitStructure.TIM_ICFilter = 0x0; //滤波
TIM_ICInit(TIM2, &TIM_ICInitStructure); //捕获设置初始化
TIM_SelectInputTrigger(TIM2, TIM_TS_TI2FP2); /* Select the TIM2 Input Trigger: TI2FP2 */
TIM_SelectSlaveMode(TIM2, TIM_SlaveMode_Reset); //复位模式为从模式
TIM_SelectMasterSlaveMode(TIM2, TIM_MasterSlaveMode_Enable); //使能主从模式
TIM_ITConfig(TIM2, TIM_IT_CC2, ENABLE); //使能CC2中断请求
TIM_Cmd(TIM2, ENABLE); //使能TIM2计数器
}
/*******************************************************************************
* Function Name : NVIC_Configuration
* Description : Configures Vector Table base location.
* Input : None
* Output : None
* Return : None
*******************************************************************************/
void NVIC_Configuration(void)
{
NVIC_InitTypeDef NVIC_InitStructure;
#ifdef VECT_TAB_RAM
/* Set the Vector Table base location at 0x20000000 */
NVIC_SetVectorTable(NVIC_VectTab_RAM, 0x0);
#else /* VECT_TAB_FLASH */
/* Set the Vector Table base location at 0x08000000 */
NVIC_SetVectorTable(NVIC_VectTab_FLASH, 0x0);
#endif
/* Configure the NVIC Preemption Priority Bits */
NVIC_PriorityGroupConfig(NVIC_PriorityGroup_0);
/* Enable the USART1 Interrupt */
NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQChannel;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
}
/*******************************************************************************
* Function Name : GPIO_Configuration
* Description : Configures the different GPIO ports.
* Input : None
* Output : None
* Return : None
*******************************************************************************/
void GPIO_Configuration(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
/* Configure PC. as Output push-pull */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6|GPIO_Pin_7|GPIO_Pin_9;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
GPIO_Init(GPIOB, &GPIO_InitStructure);
/* Configure PB9 as input floating (EXTI Line9) */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
GPIO_Init(GPIOB, &GPIO_InitStructure);
/* Configure PA3 as input floating (EXTI Line9) */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
GPIO_Init(GPIOA, &GPIO_InitStructure);
}
/*******************************************************************************
* 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 */
SysTick_CounterCmd(SysTick_Counter_Disable);
/* Clear the SysTick Counter */
SysTick_CounterCmd(SysTick_Counter_Clear);
}
/*******************************************************************************
* 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--);
}
*/
void TIM2_IRQHandler(void)
{
/* Clear TIM2 Capture compare interrupt pending bit */
if(TIM_GetITStatus(TIM2,TIM_IT_CC2)!=RESET)
{
TIM_ClearITPendingBit(TIM2, TIM_IT_CC2);
/* Get the Input Capture value */
if(aa!=10)
{
IC2Value[aa] = TIM_GetCapture2(TIM2);
//IC2Value[aa] = TIM2->CCR2;
aa++;
}
else
{
aa=0;
}
}
}
#ifdef DEBUG
/*******************************************************************************
* Function Name : assert_failed
* Description : Reports the name of the source file and the source line number
* where the assert error has occurred.
* Input : - file: pointer to the source file name
* - line: assert error line source number
* Output : None
* Return : None
*******************************************************************************/
void assert_failed(u8* file, u32 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 2007 STMicroelectronics *****END OF FILE****/
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