#include "stm32f10x.h"
#include "stm32f10x_tim.h"
#include "misc.h"
#include "stm32f10x_gpio.h" unsigned int CCR2_Val=;
extern void time_ini(void);
unsigned int capture1=;
TIM_TimeBaseInitTypeDef TIM3_TimeBaseStructure;
TIM_OCInitTypeDef TIM3_OCInitStructure;
TIM_BDTRInitTypeDef TIM3_BDTRInitStructure; void time_ini(void){
GPIO_InitTypeDef GPIO_InitStructure;
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE); //定时器3 时钟使能 GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5; //PB5复用为TIM3的通道2
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOB, &GPIO_InitStructure); /* TIM3局部复用功能开启 在TIM3的局部复用开启时，PB5会被复用为TIM3_CH2*/
GPIO_PinRemapConfig(GPIO_PartialRemap_TIM3 , ENABLE); /* Time Base configuration */
/*-------------------------------------------------------------------
TIM3CLK=72MHz 预分频系数Prescaler=63 经过分频 定时器时钟为1.125MHz
捕获/比较寄存器2 TIM3_CCR2= CCR2_Val
2通道产生的更新频率是=1.125MHz/CCR2_Val=25Hz -------------------------------------------------------------------*/
TIM3_TimeBaseStructure.TIM_Prescaler = ; //预分频器TIM3_PSC=630
TIM3_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; //计数器向上计数模式 TIM3_CR1[4]=0
TIM3_TimeBaseStructure.TIM_Period =0xffff; //自动重装载寄存器TIM3_APR
TIM3_TimeBaseStructure.TIM_ClockDivision = 0x0; //时钟分频因子 TIM3_CR1[9:8]=00 TIM_TimeBaseInit(TIM3,&TIM3_TimeBaseStructure); //写TIM3各寄存器参数 TIM3_OCInitStructure.TIM_OCMode = TIM_OCMode_Toggle ; //TIM3_CCMR1[14:12]=011 翻转 当TIM3_CCR2=TIM3_CNT时，翻转OC2REF的电平
TIM3_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //输入/捕获2输出允许 OC2信号输出到对应的输出引脚PB5
TIM3_OCInitStructure.TIM_Pulse =CCR2_Val; //若CC1通道配置为输出：CCR2是装入当前捕获/比较2 TIM3_CCR2寄存器的值（预装载值）。
//当前捕获/比较寄存器包含了与计数器TIM3_CNT比较的值，并且在OC端口上输出信号
TIM3_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low; //输出极性 低电平有效 TIM3_CCER[5]=1; TIM_OC2Init(TIM3, &TIM3_OCInitStructure);
TIM_OC2PreloadConfig(TIM3, TIM_OCPreload_Disable); //TIM3_CCMR1[1]=0 禁止TIM3_CCR2寄存器的预装载功能，可随时写入TIM3_CCR2
//且新值马上起作用 TIM_Cmd(TIM3,ENABLE); //启动定时器3 TIM3_CR1[0]=1;
TIM_ITConfig(TIM3,TIM_IT_CC2,ENABLE); //TIM3_DIER[2]=1 允许捕获/比较2中断
} void RCC_Configuration(void){ SystemInit();
RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO, ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOB | RCC_APB2Periph_GPIOC
| RCC_APB2Periph_GPIOD| RCC_APB2Periph_GPIOE , ENABLE);
} void NVIC_Configuration(void)
{
NVIC_InitTypeDef NVIC_InitStructure;
NVIC_PriorityGroupConfig(NVIC_PriorityGroup_0); NVIC_InitStructure.NVIC_IRQChannel =TIM3_IRQn ; //配置定时器中断
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = ;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = ;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
} int main(void)
{
RCC_Configuration(); //系统时钟设置及外设时钟使能
NVIC_Configuration(); //中断源配置
time_ini(); //定时器3的初始化
while();
} void TIM3_IRQHandler(void){ if (TIM_GetITStatus(TIM3, TIM_IT_CC2) != RESET) //判断状态寄存器 TIM3_SR[2] 是否发生了捕获/比较2 中断
{
TIM_ClearITPendingBit(TIM3, TIM_IT_CC2); //软件清除状态寄存器 TIM3_SR[2] 捕获/比较2 中断中断标志 capture1 = TIM_GetCapture2(TIM3); //获取TIM3_CCR2的预装值
TIM_SetCompare2(TIM3, capture1+ CCR2_Val); //和CCR2_Val累加后装入TIM3_CCR2 这是为了配合计数器值的递增。以在下一次作出比较。 } }