STM32 多通道ADC采样，采用Timer1进行采样率控制，利用DMA进行传输

STM32的里有利用Timer进行ADC采样频率控制例程，但是只有一个通道。下面是6个规则通道ADC采样，利用Timer1的第一通道进行控制，ADC采样完成后利用DMA将数据传输到SRAM里，传输完毕后产生中断，方便进行处理（本程序写于freeRTOS中，所以中断里有相关的函数）。程序经测试，运行正常。

但是对于该程序仍有一个不是很理解的地方：Timer1的第一通道进行采样控制，安装STM32手册为捕获比较，但是我不是很懂为什么要将第一通道设置成PWM1模式，而且PWM的脉宽究竟有何作用（因为我改这个参数，ADC采样频率没有改变）。

void ADC_Config(void){ ADC_InitTypeDef ADC_InitStructure;GPIO_InitTypeDef GPIO_InitStructure;NVIC_InitTypeDef NVIC_InitStructure;TIM_TimeBaseInitTypeDef   TIM_TimeBaseStructure;TIM_OCInitTypeDef         TIM_OCInitStructure;DMA_InitTypeDef DMA_InitStructure;/*******************DMA**************/ RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1,ENABLE);DMA_DeInit(DMA1_Channel1);DMA_InitStructure.DMA_PeripheralBaseAddr = ADC1_DR_Address;//外设地址DMA_InitStructure.DMA_MemoryBaseAddr = (u32)ADCdata;//内存地址DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;//dma传输方向单向DMA_InitStructure.DMA_BufferSize = 6;//设置DMA在传输时缓冲区的长度 wordDMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;//设置DMA的外设递增模式，一个外设DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;//设置DMA的内存递增模式，DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord;//外设数据字长DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;//内存数据字长DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;//设置DMA的传输模式：连续不断的循环模式 DMA_InitStructure.DMA_Priority = DMA_Priority_High;//设置DMA的优先级别DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;//设置DMA的2个memory中的变量互相访问DMA_Init(DMA1_Channel1, &DMA_InitStructure);DMA_ITConfig(DMA1_Channel1,DMA_IT_TC,ENABLE);/* Enable DMA1 channel1 */DMA_Cmd(DMA1_Channel1, ENABLE);NVIC_InitStructure.NVIC_IRQChannel=DMA1_Channel1_IRQn;NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=12;NVIC_InitStructure.NVIC_IRQChannelSubPriority=0;NVIC_InitStructure.NVIC_IRQChannelCmd=ENABLE;NVIC_Init(&NVIC_InitStructure);/*******************TIM**************/RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA|RCC_APB2Periph_GPIOC|RCC_APB2Periph_TIM1,ENABLE);  //GPIOAC时钟TIM_TimeBaseStructInit(&TIM_TimeBaseStructure); TIM_TimeBaseStructure.TIM_Period = 200;         //72M主频，每0.01s产生一次中断触发ADC。f=72M/3600/200 TIM_TimeBaseStructure.TIM_Prescaler = (3600 - 1);       TIM_TimeBaseStructure.TIM_ClockDivision = 0x0;    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;  TIM_TimeBaseInit(TIM1, &TIM_TimeBaseStructure);/* TIM1 channel1 configuration in PWM mode */TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1; TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;                TIM_OCInitStructure.TIM_Pulse = 0x7F; TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low;         TIM_OC1Init(TIM1, &TIM_OCInitStructure);/*******************ADC**************/RCC_ADCCLKConfig(RCC_CFGR_ADCPRE_DIV6);//ADC时钟PLCK2的6分频 12M。ADC最大时钟不能超过14M! RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1, ENABLE);//A口有两个通道GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4|GPIO_Pin_5;GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN;GPIO_Init(GPIOA,&GPIO_InitStructure);//C口有四个通道GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0|GPIO_Pin_1|GPIO_Pin_2|GPIO_Pin_3;GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN;GPIO_Init(GPIOC,&GPIO_InitStructure);ADC_InitStructure.ADC_Mode = ADC_Mode_Independent;       //ADC1工作在独立模式ADC_InitStructure.ADC_ScanConvMode = ENABLE;             //模数转换工作在扫描模式（多通道）ADC_InitStructure.ADC_ContinuousConvMode = DISABLE;       //模数转换工作在正常模式ADC_InitStructure.ADC_ExternalTrigConv = ADC_ExternalTrigConv_T1_CC1;    //转换外部触发启动ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;   //ADC数据右对齐ADC_InitStructure.ADC_NbrOfChannel = 6;                  //顺序进行规则转换的ADC通道的数目ADC_Init(ADC1, &ADC_InitStructure);                      //根据ADC_InitStructure中指定的参数初始化外设ADC1的寄存?//设置指定ADC的规则组通道，设置它们的转化顺序和采样时间（取最大值）ADC_RegularChannelConfig(ADC1, ADC_Channel_10 , 1, ADC_SampleTime_239Cycles5);ADC_RegularChannelConfig(ADC1, ADC_Channel_11 , 2, ADC_SampleTime_239Cycles5);ADC_RegularChannelConfig(ADC1, ADC_Channel_12, 3, ADC_SampleTime_239Cycles5);ADC_RegularChannelConfig(ADC1, ADC_Channel_13, 4, ADC_SampleTime_239Cycles5);  ADC_RegularChannelConfig(ADC1, ADC_Channel_4, 5, ADC_SampleTime_239Cycles5);ADC_RegularChannelConfig(ADC1, ADC_Channel_5, 6, ADC_SampleTime_239Cycles5);/* Enable ADC1 DMA*/ADC_DMACmd(ADC1, ENABLE);/* Enable ADC1 external trigger */ ADC_ExternalTrigConvCmd(ADC1, ENABLE);/* Enable ADC1 */ADC_Cmd(ADC1, ENABLE);/* Enable ADC1 reset calibaration register */   ADC_ResetCalibration(ADC1);/* Check the end of ADC1 reset calibration register */while(ADC_GetResetCalibrationStatus(ADC1));/* Start ADC1 calibaration */ADC_StartCalibration(ADC1);/* Check the end of ADC1 calibration */while(ADC_GetCalibrationStatus(ADC1));/* TIM1 counter enable */TIM_Cmd(TIM1, ENABLE);/* TIM1 main Output Enable */TIM_CtrlPWMOutputs(TIM1, ENABLE); }void DMA1_Channel1_IRQHandler(void){static portBASE_TYPE xHigherPriorityTaskWoken=pdFALSE;if(DMA_GetITStatus(DMA1_IT_TC1)){xSemaphoreGiveFromISR(xADCBinary,&xHigherPriorityTaskWoken);ADC_count++;DMA_ClearITPendingBit(DMA1_IT_GL1);portEND_SWITCHING_ISR( xHigherPriorityTaskWoken ); //立即切换上下文 }}

http://blog.csdn.net/jdzw_c/article/details/7315846