DAC这是为什么啊????

只看该作者 · 2011-3-18 22:37

本帖最后由 win2000_li 于 2011-3-18 22:40 编辑

const uint16_t Sine12bit[32] =
{
2047, 2447, 2831, 3185, 3498, 3750, 3939, 4056, 4095, 4056,
3939, 3750, 3495, 3185, 2831, 2447, 2047, 1647, 1263, 909,
599, 344, 155, 38, 0, 38, 155, 344, 599, 909, 1263, 1647
};

uint32_t DualSine12bit[32];
#define DAC_DHR12RD_Address  0x40007420

void RCC_Configuration(void)
{
      // Enable GPIO_AFIO GPIOA
      RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO | RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOC, ENABLE);

      // Enable DAC clock
      RCC_APB1PeriphClockCmd(RCC_APB1Periph_DAC, ENABLE);

      /* TIM6 Periph clock enable */
      RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM6, ENABLE);

      /* DMA2 clock enable */
      RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA2, ENABLE);

      // INPUT DAC AIN (PA4, PA5)
      GPIO_InitStructure.GPIO_Pin  = GPIO_Pin_4 | GPIO_Pin_5;
      GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN;
      GPIO_Init(GPIO_DAC, &GPIO_InitStructure);
}

void test(void)
{

      /* Init Structure definition */
      DAC_InitTypeDef                      DAC_InitStructure;
      TIM_TimeBaseInitTypeDef       TIM_TimeBaseStructure;

      /* TIM2 Configuration */
      TIM_TimeBaseStructInit(&TIM_TimeBaseStructure);
      TIM_TimeBaseStructure.TIM_Period = 0x4;
      TIM_TimeBaseStructure.TIM_Prescaler = 0x0;
      TIM_TimeBaseStructure.TIM_ClockDivision = 0x0;
      TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
      TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);

      /* TIM2 TRGO selection */
      TIM_SelectOutputTrigger(TIM2, TIM_TRGOSource_Update);

      /* DAC channel1 Configuration */
      DAC_InitStructure.DAC_Trigger = DAC_Trigger_T2_TRGO;
      DAC_InitStructure.DAC_WaveGeneration = DAC_WaveGeneration_Triangle;
      DAC_InitStructure.DAC_LFSRUnmask_TriangleAmplitude = DAC_TriangleAmplitude_4095;
      DAC_InitStructure.DAC_OutputBuffer = DAC_OutputBuffer_Disable;
      DAC_Init(DAC_Channel_1, &DAC_InitStructure);

      /* DAC channel2 Configuration */
      DAC_InitStructure.DAC_LFSRUnmask_TriangleAmplitude = DAC_TriangleAmplitude_4095;
      DAC_Init(DAC_Channel_2, &DAC_InitStructure);

      /* Enable DAC Channel1: Once the DAC channel1 is enabled, PA.04 is
         automatically connected to the DAC converter. */
      DAC_Cmd(DAC_Channel_1, ENABLE);

      /* Enable DAC Channel2: Once the DAC channel2 is enabled, PA.05 is
         automatically connected to the DAC converter. */
      DAC_Cmd(DAC_Channel_2, ENABLE);

      /* Set DAC dual channel DHR12RD register */
      DAC_SetDualChannelData(DAC_Align_12b_R, 4000, 2000);

      /* TIM2 enable counter */
      TIM_Cmd(TIM2, ENABLE);
}

void main()
{
SystemInit();
RCC_Configuration();
test();
while(1)
{}
}

就是没有输出波形啊???????这是为什么呢????????

没有搞懂啊!!!!!

只看该作者 · 2011-3-18 22:43

以下是调试时抓的图

只看该作者 · 2011-3-18 22:43

请大家指点...............

1万 · 2011-3-19 11:03

建议先用ST提供的DAC例子试试。

只看该作者 · 2011-3-19 15:37

// INPUT DAC AIN (PA4, PA5)
      GPIO_InitStructure.GPIO_Pin  = GPIO_Pin_4 | GPIO_Pin_5;
      GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN;
      GPIO_Init(GPIO_DAC, &GPIO_InitStructure);
                     ^^^^^^^^这个正确么？

只看该作者 · 2011-3-19 16:16

为什么不正确啊！！！

只看该作者 · 2011-3-19 16:17

00179 /**
00180 * @brief  Configures the different GPIO ports.
00181 * @param  None
00182 * @retval None
00183 */
00184 void GPIO_Configuration(void)
00185 {
00186 GPIO_InitTypeDef GPIO_InitStructure;
00187
00188 /* Once the DAC channel is enabled, the corresponding GPIO pin is automatically
00189    connected to the DAC converter. In order to avoid parasitic consumption,
00190    the GPIO pin should be configured in analog */
00191 GPIO_InitStructure.GPIO_Pin =  GPIO_Pin_4 | GPIO_Pin_5;
00192 GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN;
00193 GPIO_Init(GPIOA, &GPIO_InitStructure);
00194 }
00195
00196 /**

这里是ST的例子啊。。。。。。。。。

文档上也是这么说得啊