stm32f103zet6 DAC用DMA双通道输出

要使用DMA双通道输出DAC，你需要使用以下步骤：

1. 配置DAC输出管脚和DMA通道。

2. 配置DAC的基本参数，例如DAC数据对齐方式、DAC输出缓冲区等。

3. 配置DMA通道的基本参数，例如DMA模式、数据长度、传输方向等。

4. 设置DMA通道的源地址为要输出的数据数组。

5. 启动DMA传输。

以下是一个参考代码示例：

#include "stm32f10x.h"

#define DAC_DHR12RD_Address      0x40007420

uint16_t DAC_Buffer[512];

void DMA_Configuration(void)
{
    DMA_InitTypeDef DMA_InitStructure;
    RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);
    DMA_DeInit(DMA1_Channel2);
    DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)DAC_DHR12RD_Address;
    DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)DAC_Buffer;
    DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralDST;
    DMA_InitStructure.DMA_BufferSize = sizeof(DAC_Buffer)/sizeof(uint16_t);
    DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
    DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
    DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord;
    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(DMA1_Channel2, &DMA_InitStructure);
    DMA_Cmd(DMA1_Channel2, ENABLE);
}

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

    RCC_APB1PeriphClockCmd(RCC_APB1Periph_DAC, ENABLE);
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4 | GPIO_Pin_5;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN;
    GPIO_Init(GPIOA, &GPIO_InitStructure);

    DAC_InitStructure.DAC_Trigger = DAC_Trigger_None;
    DAC_InitStructure.DAC_WaveGeneration = DAC_WaveGeneration_None;
    DAC_InitStructure.DAC_OutputBuffer = DAC_OutputBuffer_Enable;
    DAC_Init(DAC_Channel_1, &DAC_InitStructure);
    DAC_Cmd(DAC_Channel_1, ENABLE);
    DAC_DMACmd(DAC_Channel_1, ENABLE);

    DAC_InitStructure.DAC_Trigger = DAC_Trigger_None;
    DAC_InitStructure.DAC_WaveGeneration = DAC_WaveGeneration_None;
    DAC_InitStructure.DAC_OutputBuffer = DAC_OutputBuffer_Enable;
    DAC_Init(DAC_Channel_2, &DAC_InitStructure);
    DAC_Cmd(DAC_Channel_2, ENABLE);
    DAC_DMACmd(DAC_Channel_2, ENABLE);
}

int main(void)
{
    uint16_t i;

    for (i = 0; i < sizeof(DAC_Buffer)/sizeof(uint16_t); i++)
    {
        DAC_Buffer[i] = i * 4095 / sizeof(DAC_Buffer)/sizeof(uint16_t);
    }

    DMA_Configuration();
    DAC_Configuration();

    while (1);
}

在以上代码示例中，使用DMA1的通道2输出DAC数据，DAC数据通过数组DAC_Buffer传输。DMA使用循环模式，当传输完成时会重新从DAC_Buffer开始传输。同时，使用了两个DAC通道，可以通过将数据分别传输到不同的通道来输出不同的模拟信号。