非常感谢回复，由CUBEMX 自动配置，DMA时钟在上电初始化就开启。 HAL_TIM_MspPostInit(&htim5); //配置管脚重定向 if (HAL_TIM_PWM_Init(&htim5) != HAL_OK) //DMA初始化 { Error_Handler(); } sConfigOC.OCMode = TIM_OCMODE_PWM1; sConfigOC.Pulse = 400; sConfigOC.OCPolarity = TIM_OCPOLARITY_LOW; sConfigOC.OCFastMode = TIM_OCFAST_ENABLE; HAL_TIM_OC_ConfigChannel(&htim5,&sConfigOC,TIM_CHANNEL_3); TIM5->CR1|= ((uint16_t)0x0081); TIM5->DIER &= ~TIM_DMA_UPDATE; HAL_DMA_Start_IT(&hdma_tim5_ch3_up, (uint32_t)SLOWRUN, (uint32_t)TIM5->ARR,100); DMA1->HIFCR |= (1<< 21); //清中断 //uint16_t SLOWRUN[100],值已初始化 TIM5->CCER |= 0X100; //TIM5->DIER |= TIM_DMA_UPDATE; // UDE：更新 DMA 请求使能 TIM5->DIER |= 0X101; //对着手册开启 DMA_UPDA 和TIM_UPDA 上电后直接输出PWM波形，和DMA似乎没任何关系，SLOWRUN的值似乎传不到ARR
