1 #include "stm32f10x.h"
2 #include "stm32f10x_tim.h"
3 #include "misc.h"
4 #include "stm32f10x_gpio.h"
5
6 unsigned int CCR2_Val=45000;
7 extern void time_ini(void);
8 unsigned int capture1=0;
9 TIM_TimeBaseInitTypeDef TIM3_TimeBaseStructure;
10 TIM_OCInitTypeDef TIM3_OCInitStructure;
11 TIM_BDTRInitTypeDef TIM3_BDTRInitStructure;
12
13 void time_ini(void){
14 GPIO_InitTypeDef GPIO_InitStructure;
15 RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE); //定时器3 时钟使能
16
17 GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5; //PB5复用为TIM3的通道2
18 GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
19 GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
20 GPIO_Init(GPIOB, &GPIO_InitStructure);
21
22 /* 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*/
23 GPIO_PinRemapConfig(GPIO_PartialRemap_TIM3 , ENABLE);
24
25 /* Time Base configuration */
26 /*-------------------------------------------------------------------
27 TIM3CLK=72MHz 预分频系数Prescaler=63 经过分频 定时器时钟为1.125MHz
28 捕获/比较寄存器2 TIM3_CCR2= CCR2_Val
29 2通道产生的更新频率是=1.125MHz/CCR2_Val=25Hz
30
31 -------------------------------------------------------------------*/
32 TIM3_TimeBaseStructure.TIM_Prescaler = 630; //预分频器TIM3_PSC=630
33 TIM3_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; //计数器向上计数模式 TIM3_CR1[4]=0
34 TIM3_TimeBaseStructure.TIM_Period =0xffff; //自动重装载寄存器TIM3_APR
35 TIM3_TimeBaseStructure.TIM_ClockDivision = 0x0; //时钟分频因子 TIM3_CR1[9:8]=00
36
37 TIM_TimeBaseInit(TIM3,&TIM3_TimeBaseStructure); //写TIM3各寄存器参数
38
39 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
40 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
41 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）。
42 //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
43 TIM3_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low; //输出极性 低电平有效 TIM3_CCER[5]=1;
44
45 TIM_OC2Init(TIM3, &TIM3_OCInitStructure);
46 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
47 //且新值马上起作用
48
49 TIM_Cmd(TIM3,ENABLE); //启动定时器3 TIM3_CR1[0]=1;
50 TIM_ITConfig(TIM3,TIM_IT_CC2,ENABLE); //TIM3_DIER[2]=1 允许捕获/比较2中断
51 }
52
53 void RCC_Configuration(void){
54
55 SystemInit();
56 RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO, ENABLE);
57 RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOB | RCC_APB2Periph_GPIOC
58 | RCC_APB2Periph_GPIOD| RCC_APB2Periph_GPIOE , ENABLE);
59 }
60
61 void NVIC_Configuration(void)
62 {
63 NVIC_InitTypeDef NVIC_InitStructure;
64 NVIC_PriorityGroupConfig(NVIC_PriorityGroup_0);
65
66 NVIC_InitStructure.NVIC_IRQChannel =TIM3_IRQn ; //配置定时器中断
67 NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
68 NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
69 NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
70 NVIC_Init(&NVIC_InitStructure);
71 }
72
73 int main(void)
74 {
75 RCC_Configuration(); //系统时钟设置及外设时钟使能
76 NVIC_Configuration(); //中断源配置
77 time_ini(); //定时器3的初始化
78 while(1);
79 }
80
81 void TIM3_IRQHandler(void){
82
83 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
84 {
85 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
86
87 capture1 = TIM_GetCapture2(TIM3); //获取TIM3_CCR2的预装值
88 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。
89
90 }
91
92 }
