STM32F103單片機輸出1Mhz方波有過沖產生怎么解決附上程序和波形
單片機源程序如下:
- #include "timer.h"
- #include "led.h"
- #include "usart.h"
- #include "delay.h"
-
- //TIM3 PWM部分初始化
- //PWM輸出初始化
- //arr：自動重裝值
- //psc：時鐘預分頻數
- void TIM2_PWM_Init(u16 arr,u16 psc)
- {
- GPIO_InitTypeDef GPIO_InitStructure;
- TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
- TIM_OCInitTypeDef TIM_OCInitStructure;
-
- RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE); //使能定時器3時鐘
- RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_AFIO, ENABLE); //使能GPIO外設和AFIO復用功能模塊時鐘
-
- //GPIO_PinRemapConfig(GPIO_PartialRemap_TIM3, ENABLE); //Timer3部分重映射 TIM3_CH2->PB5
-
- //設置該引腳為復用輸出功能,輸出TIM3 CH2的PWM脈沖波形 GPIOA.1
- GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1; //TIM_CH2
- GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP; //復用推挽輸出
- GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
- GPIO_Init(GPIOA, &GPIO_InitStructure);//初始化GPIO
-
- //初始化TIM3
- TIM_TimeBaseStructure.TIM_Period = arr; //設置在下一個更新事件裝入活動的自動重裝載寄存器周期的值
- TIM_TimeBaseStructure.TIM_Prescaler =psc; //設置用來作為TIMx時鐘頻率除數的預分頻值
- TIM_TimeBaseStructure.TIM_ClockDivision = 0; //設置時鐘分割:TDTS = Tck_tim
- TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; //TIM向上計數模式
- TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure); //根據TIM_TimeBaseInitStruct中指定的參數初始化TIMx的時間基數單位
-
- //初始化TIM3 Channel2 PWM模式
- TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2; //選擇定時器模式:TIM脈沖寬度調制模式2
- TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //比較輸出使能
- TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low ; //輸出極性:TIM輸出比較極性高
- TIM_OC2Init(TIM2, &TIM_OCInitStructure); //根據T指定的參數初始化外設TIM3 OC2
- TIM_OC2PreloadConfig(TIM2, TIM_OCPreload_Enable); //使能TIM3在CCR2上的預裝載寄存器
-
- TIM_Cmd(TIM2, DISABLE);
-
- }
- void TIM4_Init(unsigned short int arr, unsigned short int psc)
- {
- TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStructure; /*定義一個設置定時器的變量*/
- NVIC_InitTypeDef NVIC_InitStructure; /*定義一個設置中斷的變量*/
-
- NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2); /*設置中斷向量分組：第2組 搶先優先級：0 1 2 3 子優先級：0 1 2 3*/
- RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4,ENABLE); /*使能TIM4時鐘*/
- TIM_TimeBaseInitStructure.TIM_Period = arr; /*設置自動重裝載值*/
- TIM_TimeBaseInitStructure.TIM_Prescaler=psc; /*設置定時器預分頻數*/
- TIM_TimeBaseInitStructure.TIM_CounterMode=TIM_CounterMode_Up; /*向上計數模式*/
- TIM_TimeBaseInitStructure.TIM_ClockDivision=TIM_CKD_DIV1; /*1分頻*/
- TIM_TimeBaseInit(TIM4,&TIM_TimeBaseInitStructure); /*設置TIM4*/
-
- TIM_ClearITPendingBit(TIM4,TIM_IT_Update); /*清除溢出中斷標志位*/
- TIM_ITConfig(TIM4,TIM_IT_Update,ENABLE); /*使能TIM4溢出中斷*/
-
-
- NVIC_InitStructure.NVIC_IRQChannel=TIM4_IRQn; /*設置TIM4中斷*/
- NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=1; /*搶占優先級1*/
- NVIC_InitStructure.NVIC_IRQChannelSubPriority=1; /*子優先級0*/
- NVIC_InitStructure.NVIC_IRQChannelCmd=ENABLE; /*中斷通道使能*/
- NVIC_Init(&NVIC_InitStructure); /*設置中斷*/
- TIM_Cmd(TIM4,ENABLE);
- }
- void TIM4_IRQHandler(void)
- {
- if(TIM_GetITStatus(TIM4, TIM_IT_Update) != RESET) /*如果TIM_IT_Update置位，表示TIM4溢出中斷，進入if*/
- {
- TIM_Cmd(TIM2, ENABLE);
- delay_us(8);
- TIM_Cmd(TIM2, DISABLE);
-
- TIM_ClearITPendingBit(TIM4, TIM_IT_Update); /*清除TIM4溢出中斷標志*/
- }
- }
所有資料51hei提供下載:
PWM輸出實驗.7z
(186.51 KB, 下載次數: 55)
2019-7-30 23:04 上傳
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