[求助] STM32的DAC输出固定电压值，采用DMA方式，发现输出不了电压

伊轩海 2015-1-13 11:36 楼主

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利用DAC的DMA方式输出电压值，发现输出不了，麻烦看看下面程序，指导一下，谢谢！

DAC函数dac.c
#include "dac.h"
#define DAC_DHR12R1_Address 0x40007408  //
u16 DAC_tablevalue[32];
void DMA2_Init(void)
{
DMA_InitTypeDef  DMA_InitStructure;
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA2, ENABLE);//
DMA_DeInit(DMA2_Channel3);

DMA_InitStructure.DMA_PeripheralBaseAddr = DAC_DHR12R1_Address;//
DMA_InitStructure.DMA_MemoryBaseAddr = (u32)&DAC_tablevalue;//

DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralDST;//
DMA_InitStructure.DMA_BufferSize = 32;//

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_Mode = DMA_Mode_Normal;  //
//DMA_InitStructure.DMA_Priority = DMA_Priority_High;
DMA_InitStructure.DMA_Priority = DMA_Priority_Medium;

DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;//·

DMA_Init(DMA2_Channel3, &DMA_InitStructure);//
DMA_Cmd(DMA2_Channel3, ENABLE);//
}

//DAC配置
void Dac1_Init(void)
{

GPIO_InitTypeDef GPIO_InitStructure;
DAC_InitTypeDef DAC_InitType;

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

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4;       //
      GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN; //
      GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
      GPIO_Init(GPIOA, &GPIO_InitStructure);

GPIO_SetBits(GPIOA,GPIO_Pin_4)       ;//PA.4置高

DAC_InitType.DAC_Trigger=DAC_Trigger_None;       //
DAC_InitType.DAC_WaveGeneration=DAC_WaveGeneration_None;//
DAC_InitType.DAC_LFSRUnmask_TriangleAmplitude=DAC_LFSRUnmask_Bit0;//
DAC_InitType.DAC_OutputBuffer=DAC_OutputBuffer_Disable ;       //
DAC_Init(DAC_Channel_1,&DAC_InitType);       //

DAC_Cmd(DAC_Channel_1, ENABLE);  //使能DAC1

DAC_DMACmd(DAC_Channel_1, ENABLE);//使能DAC1的DMA

}

void DAC_Mode_Init(void)
{

Dac1_Init();       //DAC初始化

DMA2_Init();
DAC_tablevalue[0] = 2048;//DAC输出一个固定电压值

}

主函数main.c
int main(void)
{
DAC_Mode_Init();
while(1);
}