使用TIM+DAC+DMA时同时打开TIM和DMA中断出现异常

ggcock · 发表于 2015-11-6 15:30:03

我使用TIM+DAC+DMA的配置生成正弦波。用TIM7作为触发源，DAC1转换，DMA2 CH3传输数据。

实测时，我希望同时代开TIM7和DMA2_CH3的中断，目的是检查每秒的转换次数和DMA搬运次数。

我设定的TIM7溢出频率是16000Hz，数据源的尺寸是32字节。

如果单独打开TIM7溢出中断，可以看到每秒钟转换次数是16000次。

如果单独打开DMA传输完成中断，可以看到每秒搬运了500组数据（16000/32=500)。

然后问题来了：如果同时打开TIM7的溢出中断和DMA传输完成中断，则DAC没有得到一次转换，DMA也没有进行任何一次搬运。但是可以看到TIM7每秒的溢出次数仍然是正确的16000。

是不是在这种配置下面TIM发出的Update事件被截获或者是被屏蔽了，导致DAC得不到触发？

以下附上代码

[mw_shl_code=c,true]void User_Init_DAC(uint32_t bOn) { GPIO_InitTypeDef GPIO_InitStructure; DAC_InitTypeDef DAC_InitStructure; DMA_InitTypeDef DMA_InitStructure; NVIC_InitTypeDef NVIC_InitStructure,NVIC_InitStructure1; uint16_t PrescalerValue = 0; if(bOn) { // Periph clock enable RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE); RCC_APB1PeriphClockCmd(RCC_APB1Periph_DAC, ENABLE); RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA2, ENABLE); RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM7, ENABLE); GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN; GPIO_Init(GPIOA, &GPIO_InitStructure); // Reset TIM7 TIM_DeInit(TIM7); // TIM6 Configuration TIM_PrescalerConfig(TIM7, 44, TIM_PSCReloadMode_Update); //分频系数为 PSC+1 =15 TIM_SetAutoreload(TIM7, 99); //计数系数为 ARR+1 =100 // TIM7 TRGO selection TIM_SelectOutputTrigger(TIM7, TIM_TRGOSource_Update); // TIM Interrupts enable NVIC_InitStructure1.NVIC_IRQChannel = TIM7_IRQn; NVIC_InitStructure1.NVIC_IRQChannelPreemptionPriority = 3; NVIC_InitStructure1.NVIC_IRQChannelSubPriority = 1; NVIC_InitStructure1.NVIC_IRQChannelCmd = ENABLE; NVIC_Init(&NVIC_InitStructure1); TIM_ITConfig(TIM7, TIM_IT_Update, ENABLE); /* DAC channel1 Configuration */ DAC_InitStructure.DAC_Trigger = DAC_Trigger_T7_TRGO; //DAC_InitStructure.DAC_Trigger = DAC_Trigger_Software; DAC_InitStructure.DAC_WaveGeneration = DAC_WaveGeneration_None; DAC_InitStructure.DAC_OutputBuffer = DAC_OutputBuffer_Disable; DAC_Init(DAC_Channel_1, &DAC_InitStructure); DMA_DeInit(DMA2_Channel3); DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)&DAC->DHR12R1; DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)&Sine12bit; //change DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralDST; DMA_InitStructure.DMA_BufferSize = 32; //32; DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable; DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable; DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Word; DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord; DMA_InitStructure.DMA_Mode = DMA_Mode_Circular; DMA_InitStructure.DMA_Priority = DMA_Priority_High; DMA_InitStructure.DMA_M2M = DMA_M2M_Disable; DMA_Init(DMA2_Channel3, &DMA_InitStructure); //DMA Interrupt enable NVIC_InitStructure.NVIC_IRQChannel = DMA2_Channel3_IRQn; NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 3; NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1; NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; NVIC_Init(&NVIC_InitStructure); DMA_ITConfig(DMA2_Channel3,DMA_IT_HT|DMA_IT_TC,ENABLE); // Enable DMA2 Channel3 DMA_Cmd(DMA2_Channel3, ENABLE); // Enable DAC DAC_Cmd(DAC_Channel_1, ENABLE); // Enable DMA for DAC Channel1 DAC_DMACmd(DAC_Channel_1, ENABLE); TIM_Cmd(TIM7, ENABLE); } else { TIM_DeInit(TIM7); } } [/mw_shl_code]