stm32f4三重交替采样具体代码

以下是一个基于STM32F4的DAC三重交替采样的示例代码：

#include "stm32f4xx.h"

#define DAC_DHR12R2_ADDRESS      0x40007414
#define DAC_DHR12R1_ADDRESS      0x40007408

void DAC_Config(void);
void TIM6_Config(void);

uint16_t DAC_Buffer[3] = {0x0000, 0x1000, 0x2000};
uint8_t DAC_Buffer_Index = 0;

int main(void)
{
    DAC_Config();
    TIM6_Config();

    while(1)
    {
    }
}

void DAC_Config(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;
    DAC_InitTypeDef DAC_InitStructure;

    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE); //Enable GPIOA clock
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_DAC, ENABLE); //Enable DAC clock

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4 | GPIO_Pin_5; //PA4 and PA5 for DAC1 and DAC2
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AN; //Analog mode
    GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL; //No pull-up/down
    GPIO_Init(GPIOA, &GPIO_InitStructure);

    DAC_InitStructure.DAC_Trigger = DAC_Trigger_T6_TRGO; //TIM6 TRGO as trigger
    DAC_InitStructure.DAC_WaveGeneration = DAC_WaveGeneration_None; //No wave generation
    DAC_InitStructure.DAC_OutputBuffer = DAC_OutputBuffer_Enable; //Output buffer enabled
    DAC_Init(DAC_Channel_1, &DAC_InitStructure); //Configure DAC1
    DAC_Init(DAC_Channel_2, &DAC_InitStructure); //Configure DAC2

    DAC_Cmd(DAC_Channel_1, ENABLE); //Enable DAC1
    DAC_Cmd(DAC_Channel_2, ENABLE); //Enable DAC2
}

void TIM6_Config(void)
{
    TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
    TIM_OCInitTypeDef TIM_OCInitStructure;

    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM6, ENABLE); //Enable TIM6 clock

    TIM_TimeBaseStructure.TIM_Period = 99; //100kHz (SystemCoreClock/100k)
    TIM_TimeBaseStructure.TIM_Prescaler = 0;
    TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseInit(TIM6, &TIM_TimeBaseStructure);

    TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_Timing;
    TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
    TIM_OCInitStructure.TIM_Pulse = 50; //50% duty cycle
    TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
    TIM_OC1Init(TIM6, &TIM_OCInitStructure); //Configure TIM6 Channel 1 as output compare timing mode
    TIM_SelectOutputTrigger(TIM6, TIM_TRGOSource_OC1); //Select TIM6 OC1 as trigger output

    TIM_Cmd(TIM6, ENABLE); //Enable TIM6
    TIM_ITConfig(TIM6, TIM_IT_Update, ENABLE); //Enable TIM6 update interrupt
    NVIC_EnableIRQ(TIM6_DAC_IRQn); //Enable TIM6 interrupt in NVIC
}

void TIM6_DAC_IRQHandler(void)
{
    if(TIM_GetITStatus(TIM6, TIM_IT_Update) != RESET) //Check if TIM6 update interrupt occurred
    {
        TIM_ClearITPendingBit(TIM6, TIM_IT_Update); //Clear TIM6 update interrupt flag

        if(DAC_Buffer_Index == 0) //If first buffer is being output
        {
            DAC_SetChannel1Data(DAC_DHR12R1_ADDRESS, DAC_Align_12b_R, DAC_Buffer[1]); //Load second buffer to DAC1
            DAC_SetChannel2Data(DAC_DHR12R2_ADDRESS, DAC_Align_12b_R, DAC_Buffer[2]); //Load third buffer to DAC2
            DAC_Buffer_Index++; //Increment buffer index
        }
        else if(DAC_Buffer_Index == 1) //If second buffer is being output
        {
            DAC_SetChannel1Data(DAC_DHR12R1_ADDRESS, DAC_Align_12b_R, DAC_Buffer[2]); //Load third buffer to DAC1
            DAC_SetChannel2Data(DAC_DHR12R2_ADDRESS, DAC_Align_12b_R, DAC_Buffer[0]); //Load first buffer to DAC2
            DAC_Buffer_Index++; //Increment buffer index
        }
        else //If third buffer is being output
        {
            DAC_SetChannel1Data(DAC_DHR12R1_ADDRESS, DAC_Align_12b_R, DAC_Buffer[0]); //Load first buffer to DAC1
            DAC_SetChannel2Data(DAC_DHR12R2_ADDRESS, DAC_Align_12b_R, DAC_Buffer[1]); //Load second buffer to DAC2
            DAC_Buffer_Index = 0; //Reset buffer index
        }
    }
}

该代码使用了STM32F4的DAC和TIM6模块来实现三重交替采样。DAC的输出由三个缓冲区组成，每个缓冲区包含一个16位的DAC数据。TIM6被配置为100kHz的定时器，其输出比较通道1被用作触发器来触发DAC的输出。每当TIM6触发器被触发时，DAC会输出当前缓冲区中的数据，并将下一个缓冲区的数据加载到DAC中，实现三重交替采样。在中断服务程序中，使用DAC_Buffer_Index变量来跟踪当前正在输出的缓冲区。当输出完第一个缓冲区时，将第二个和第三个缓冲区的数据加载到DAC中，并将缓冲区索引增加1。当输出完第二个缓冲区时，将第三个和第一个缓冲区的数据加载到DAC中，并将缓冲区索引增加1。当输出完第三个缓冲区时，将第一个和第二个缓冲区的数据加载到DAC中，并将缓冲区索引重置为0