TIM_G etCapture2(TIM2)计算周期

定时器从0开始计数,计数到TIM_Period后,重新归零再计数。

捕获只是把发生捕获时刻的计数器当前值拷贝下来,你的IC2Value就是这个数值。

如果配置了 发生捕获时复位计数器,则计数器没有计数到TIM_Period时也被归零并重新计数。

如果你配置比较小的TIM_Period数值,则可能在还没有发生捕获时,计数器就被归零,所以你要在软件中记录下计数器被归零的次数。

当计数器的时钟频率为F时,计数器每计数一次表示1/F的时间,因此从捕获寄存器中读出的数值表示了一个时间。如果配置了发生捕获时复位计数器,则这个时间恰好就是要捕获信号的周期。

从上面原理可以看出,TIM_Period的数值与捕获的精度没有关系。
#include "stm32f10x.h" // Device header void PWM_Init(void) { RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE); RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE); // RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO, ENABLE); // GPIO_PinRemapConfig(GPIO_PartialRemap1_TIM2, ENABLE); // GPIO_PinRemapConfig(GPIO_Remap_SWJ_JTAGDisable, ENABLE); GPIO_InitTypeDef GPIO_InitStructure; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP; GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1|GPIO_Pin_2; GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; GPIO_Init(GPIOA, &GPIO_InitStructure); TIM_InternalClockConfig(TIM2); TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStructure; TIM_TimeBaseInitStructure.TIM_ClockDivision = TIM_CKD_DIV1; TIM_TimeBaseInitStructure.TIM_CounterMode = TIM_CounterMode_Up; TIM_TimeBaseInitStructure.TIM_Period = 20000 - 1; //ARR TIM_TimeBaseInitStructure.TIM_Prescaler = 72 - 1; //PSC TIM_TimeBaseInitStructure.TIM_RepetitionCounter = 0; TIM_TimeBaseInit(TIM2, &TIM_TimeBaseInitStructure); TIM_OCInitTypeDef TIM_OCInitStructure; TIM_OCStructInit(&TIM_OCInitStructure); TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1; TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; TIM_OCInitStructure.TIM_Pulse = 0; //CCR TIM_OC2Init(TIM2, &TIM_OCInitStructure); TIM_OC3Init(TIM2, &TIM_OCInitStructure); TIM_OC3PreloadConfig(TIM2, TIM_OCPreload_Enable); TIM_ARRPreloadConfig(TIM2, ENABLE); TIM_Cmd(TIM2, ENABLE); } void PWM_SetCompare2(uint16_t Compare) { TIM_SetCompare2(TIM2, Compare); } void PWM_SetCompare3(uint16_t Compare) { TIM_SetCompare3(TIM2, Compare); }
最新发布
07-15
#include "stm32f10x.h" // Device header void PWM_Init(void) { RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE); RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE); // RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO, ENABLE); // GPIO_PinRemapConfig(GPIO_PartialRemap1_TIM2, ENABLE); // GPIO_PinRemapConfig(GPIO_Remap_SWJ_JTAGDisable, ENABLE); GPIO_InitTypeDef GPIO_InitStructure; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP; GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1|GPIO_Pin_2; GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; GPIO_Init(GPIOA, &GPIO_InitStructure); TIM_InternalClockConfig(TIM2); TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStructure; TIM_TimeBaseInitStructure.TIM_ClockDivision = TIM_CKD_DIV1; TIM_TimeBaseInitStructure.TIM_CounterMode = TIM_CounterMode_Up; TIM_TimeBaseInitStructure.TIM_Period = 20000 - 1; //ARR TIM_TimeBaseInitStructure.TIM_Prescaler = 72 - 1; //PSC TIM_TimeBaseInitStructure.TIM_RepetitionCounter = 0; TIM_TimeBaseInit(TIM2, &TIM_TimeBaseInitStructure); TIM_OCInitTypeDef TIM_OCInitStructure; TIM_OCStructInit(&TIM_OCInitStructure); TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1; TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; TIM_OCInitStructure.TIM_Pulse = 0; //CCR TIM_OC2Init(TIM2, &TIM_OCInitStructure); TIM_ARRPreloadConfig(TIM2, ENABLE); TIM_Cmd(TIM2, ENABLE); } void PWM_SetCompare2(uint16_t Compare) { TIM_SetCompare2(TIM2, Compare); } void PWM_SetCompare3(uint16_t Compare) { TIM_SetCompare3(TIM3, Compare); }
07-15
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