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本帖最后由 ZSR20181017 于 2019-9-26 15:21 编辑
问题是:PWM可以输出,频率和占空比都对,但是PWM方波的个数无法指定?
static void TIM_Channel_GPIO_Config(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB,ENABLE);
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOB, &GPIO_InitStructure);
}
static void BaseTime_Config(void)
{
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
//开启定时器时钟
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4,ENABLE);//RCC_APB1Periph_TIM4
// RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1,ENABLE);
TIM_DeInit(TIM4);
TIM_TimeBaseStructure.TIM_Period = (10-1);
TIM_TimeBaseStructure.TIM_Prescaler = 71;
TIM_TimeBaseStructure.TIM_ClockDivision=TIM_CKD_DIV1;
TIM_TimeBaseStructure.TIM_CounterMode=TIM_CounterMode_Up;
TIM_TimeBaseStructure.TIM_RepetitionCounter=0;
// TIM_TimeBaseStructure.TIM_RepetitionCounter=10;
//初始化基本定时器
TIM_TimeBaseInit(TIM4,&TIM_TimeBaseStructure);
//清除计数器中断标志
// TIM_ClearFlag(TIM4,TIM_FLAG_Update);
//开启计数器中断
// TIM_ITConfig(TIM4,TIM_IT_Update,ENABLE);
// TIM_SelectOutputTrigger(TIM4,TIM_TRGOSource_OC3Ref);//TIM4的OC3REF信号做为触发输出
TIM_OCInitTypeDef TIM_OCInitStructure;
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_OutputNState = TIM_OutputNState_Disable;
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
TIM_OCInitStructure.TIM_Pulse = 3;
TIM_OC3Init(TIM4, &TIM_OCInitStructure);
TIM_OC3PreloadConfig(TIM4, TIM_OCPreload_Enable);
// TIM_CtrlPWMOutputs(TIM4,ENABLE);
//
// TIM_ARRPreloadConfig(TIM4, ENABLE);
//使能定时器
TIM_Cmd(TIM4,ENABLE);
// TIM_Cmd(TIM4,DISABLE);
DMA_InitTypeDef DMA_InitStructure;
DMA_DeInit(DMA1_Channel5);
DMA_InitStructure.DMA_PeripheralBaseAddr = (u32)&TIM4->CCR1;//TIM4->CCR1
DMA_InitStructure.DMA_MemoryBaseAddr = (u32)buff;
DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;
DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord;
DMA_InitStructure.DMA_BufferSize = 10;
DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralDST;
DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;
DMA_InitStructure.DMA_Priority = DMA_Priority_High;
DMA_InitStructure.DMA_M2M = DMA_M2M_Enable;
DMA_Init(DMA1_Channel5,&DMA_InitStructure);//DMA1_Channel1
DMA_ITConfig(DMA1_Channel5,DMA_IT_TC,ENABLE);//DMA1_Channel1
DMA_ClearFlag( DMA1_FLAG_TC5 );//DMA1_FLAG_TC1
TIM_DMACmd(TIM4, TIM_DMA_Update, ENABLE);
DMA_Cmd(DMA1_Channel5,ENABLE);//DMA1_Channel1
}
/*中断服务函数*/
void DMA1_Channel5_IRQHandler(void)
{
if(DMA_GetITStatus(DMA1_IT_TC5) != RESET )
{
DMA_ClearITPendingBit(DMA1_IT_TC5);
DMA_Cmd(DMA1_Channel5,DISABLE);
TIM_Cmd(TIM4,DISABLE);
}
}
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