stm32 DAC电压输出问题

只看该作者 · 2014-3-7 21:09

PA4无电压输出啊！求解！！！
DAC配置如下：
void Dac1_Init(void)
{

      DAC_InitTypeDef DAC_InitStruct;

      GPIO_InitTypeDef GPIO_InitStructure;

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

      /* Configure DAC channe1 outputs pins */
      GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4;
      GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

      GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN;
      GPIO_Init(GPIOA, &GPIO_InitStructure);

      DAC_DeInit();

      //DAC_Cmd(DAC_Channel_1,ENABLE); //
//DAC_Cmd(DAC_Channel_2, ENABLE);
      DAC_StructInit(&DAC_InitStruct);//将DAC_Struct的值设为默认
      DAC_InitStruct.DAC_Trigger=DAC_Trigger_Software;//由软件触发
      DAC_InitStruct.DAC_WaveGeneration=DAC_WaveGeneration_None;//关闭波形生成
      DAC_InitStruct.DAC_LFSRUnmask_TriangleAmplitude=DAC_TriangleAmplitude_4095;
      DAC_InitStruct.DAC_OutputBuffer=DAC_OutputBuffer_Disable;//使能DAC通道缓存
      DAC_Init(DAC_Channel_1,&DAC_InitStruct);
/* Enable DAC Channel1 */

      DAC_DualSoftwareTriggerCmd(ENABLE);//使能软件触发,更新DAC的值
      DAC_SetChannel1Data(DAC_Align_12b_R,4000);//12位右对齐,
      DAC_SoftwareTriggerCmd(DAC_Channel_1, ENABLE);
      DAC_Cmd(DAC_Channel_1, ENABLE);

}
主函数中：
Dac1_Init();          DAC_SetChannel1Data(DAC_Align_12b_R, 4000); DAC_SoftwareTriggerCmd(DAC_Channel_1, ENABLE);
测PA4无电压输出啊！求解！！！