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DAC正弦波例子没有波形输出问题

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wonderfully|  楼主 | 2010-12-11 09:09 | 只看该作者 回帖奖励 |倒序浏览 |阅读模式
我看资料是PA.4为DAC输出口,将例程写入后,用万用表一个点到VREF-,一个点到29脚,如果有正弦波输出,电压值应该是不停变化,但是现在是只有一个1.6V的稳定电压,求高手看看哪里出错了。板是大虾DX32。

/******************** (C) COPYRIGHT 2008 STMicroelectronics ********************
* File Name          : main.c
* Author             : MCD Application Team
* Version            : V2.0
* Date               : 05/23/2008
* Description        : Main program body.
********************************************************************************
* THE PRESENT FIRMWARE WHICH IS FOR GUIDANCE ONLY AIMS AT PROVIDING CUSTOMERS
* WITH CODING INFORMATION REGARDING THEIR PRODUCTS IN ORDER FOR THEM TO SAVE TIME.
* AS A RESULT, STMICROELECTRONICS SHALL NOT BE HELD LIABLE FOR ANY DIRECT,
* INDIRECT OR CONSEQUENTIAL DAMAGES WITH RESPECT TO ANY CLAIMS ARISING FROM THE
* CONTENT OF SUCH SOFTWARE AND/OR THE USE MADE BY CUSTOMERS OF THE CODING
* INFORMATION CONTAINED HEREIN IN CONNECTION WITH THEIR PRODUCTS.
* FOR MORE INFORMATION PLEASE CAREFULLY READ THE LICENSE AGREEMENT FILE LOCATED
* IN THE ROOT DIRECTORY OF THIS FIRMWARE PACKAGE.
*******************************************************************************/
/* Includes ------------------------------------------------------------------*/
#include "stm32f10x_lib.h"
/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
#define DAC_DHR12RD_Address      0x40007420
/* Init Structure definition */
DAC_InitTypeDef            DAC_InitStructure;
DMA_InitTypeDef            DMA_InitStructure;
TIM_TimeBaseInitTypeDef    TIM_TimeBaseStructure;
/* Private macro -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
ErrorStatus HSEStartUpStatus;
uc16 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};
u32 DualSine12bit[32];
u8 Idx = 0;
/* Private function prototypes -----------------------------------------------*/
void RCC_Configuration(void);
void GPIO_Configuration(void);
void NVIC_Configuration(void);
void Delay(vu32 nCount);
/* Private functions ---------------------------------------------------------*/
/*******************************************************************************
* Function Name  : main
* Description    : Main program.
* Input          : None
* Output         : None
* Return         : None
*******************************************************************************/
int main(void)
{
#ifdef DEBUG
  debug();
#endif
  /* System Clocks Configuration */
  RCC_Configuration();   
  /* GPIO configuration */
  GPIO_Configuration();
  /* NVIC Configuration */
  NVIC_Configuration();
  /* TIM8 Configuration */
  /* Time base configuration */
  TIM_TimeBaseStructInit(&TIM_TimeBaseStructure);
  TIM_TimeBaseStructure.TIM_Period = 0x19;         
  TIM_TimeBaseStructure.TIM_Prescaler = 0x0;      
  TIM_TimeBaseStructure.TIM_ClockDivision = 0x0;   
  TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;  
  TIM_TimeBaseInit(TIM8, &TIM_TimeBaseStructure);
  /* TIM8 TRGO selection */
  TIM_SelectOutputTrigger(TIM8, TIM_TRGOSource_Update);
  /* DAC channel1 Configuration */
  DAC_StructInit(&DAC_InitStructure);
  DAC_InitStructure.DAC_Trigger = DAC_Trigger_T8_TRGO;
  DAC_InitStructure.DAC_WaveGeneration = DAC_WaveGeneration_None;
  DAC_InitStructure.DAC_OutputBuffer = DAC_OutputBuffer_Disable;
  DAC_Init(DAC_Channel_1, &DAC_InitStructure);
  /* DAC channel2 Configuration */
  DAC_Init(DAC_Channel_2, &DAC_InitStructure);
  /* Fill Sine32bit table */
  for (Idx= 0; Idx<32; Idx++)
  {
    DualSine12bit[Idx] = (Sine12bit[Idx] << 16) + (Sine12bit[Idx]);
  }
  /* DMA2 channel4 configuration */
  DMA_DeInit(DMA2_Channel4);
  DMA_InitStructure.DMA_PeripheralBaseAddr = DAC_DHR12RD_Address;
  DMA_InitStructure.DMA_MemoryBaseAddr = (u32)&DualSine12bit;
  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_Word;
  DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Word;
  DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;
  DMA_InitStructure.DMA_Priority = DMA_Priority_High;
  DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
  DMA_Init(DMA2_Channel4, &DMA_InitStructure);
  /* Enable DMA2 Channel4 */
  DMA_Cmd(DMA2_Channel4, ENABLE);
  /* Enable DAC Channel1 */
  DAC_Cmd(DAC_Channel_1, ENABLE);
  /* Enable DAC Channel2 */
  DAC_Cmd(DAC_Channel_2, ENABLE);
  /* Enable DMA for DAC Channel2 */
  DAC_DMACmd(DAC_Channel_2, ENABLE);
  /* TIM8 enable counter */
  TIM_Cmd(TIM8, ENABLE);
  while (1)
  {
  }
}
/*******************************************************************************
* Function Name  : RCC_Configuration
* Description    : Configures the different system clocks.
* Input          : None
* Output         : None
* Return         : None
*******************************************************************************/
void RCC_Configuration(void)
{   
  /* RCC system reset(for debug purpose) */
  RCC_DeInit();
  /* Enable HSE */
  RCC_HSEConfig(RCC_HSE_ON);
  /* Wait till HSE is ready */
  HSEStartUpStatus = RCC_WaitForHSEStartUp();
  if(HSEStartUpStatus == SUCCESS)
  {
    /* Enable Prefetch Buffer */
    FLASH_PrefetchBufferCmd(FLASH_PrefetchBuffer_Enable);
    /* Flash 2 wait state */
    FLASH_SetLatency(FLASH_Latency_2);
  
    /* HCLK = SYSCLK */
    RCC_HCLKConfig(RCC_SYSCLK_Div1);
  
    /* PCLK2 = HCLK */
    RCC_PCLK2Config(RCC_HCLK_Div1);
    /* PCLK1 = HCLK/2 */
    RCC_PCLK1Config(RCC_HCLK_Div2);
    /* PLLCLK = 8MHz * 9 = 72 MHz */
    RCC_PLLConfig(RCC_PLLSource_HSE_Div1, RCC_PLLMul_9);
    /* Enable PLL */
    RCC_PLLCmd(ENABLE);
    /* Wait till PLL is ready */
    while(RCC_GetFlagStatus(RCC_FLAG_PLLRDY) == RESET)
    {
    }
    /* Select PLL as system clock source */
    RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK);
    /* Wait till PLL is used as system clock source */
    while(RCC_GetSYSCLKSource() != 0x08)
    {
    }
  }
/* Enable peripheral clocks --------------------------------------------------*/
  /* DMA clock enable */
  RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA2, ENABLE);
  /* AFIO and GPIOA Periph clock enable */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO | RCC_APB2Periph_GPIOA, ENABLE);
  /* DAC Periph clock enable */
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_DAC, ENABLE);
  /* TIM8 Periph clock enable */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM8, ENABLE);
}
/*******************************************************************************
* Function Name  : GPIO_Configuration
* Description    : Configures the different GPIO ports.
* Input          : None
* Output         : None
* Return         : None
*******************************************************************************/
void GPIO_Configuration(void)
{
  GPIO_InitTypeDef GPIO_InitStructure;
  /* Configure DAC channe1 and DAC channel2 outputs pins */
  GPIO_InitStructure.GPIO_Pin =  GPIO_Pin_4 | GPIO_Pin_5;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
  GPIO_Init(GPIOA, &GPIO_InitStructure);
}
/*******************************************************************************
* Function Name  : NVIC_Configuration
* Description    : Configures Vector Table base location.
* Input          : None
* Output         : None
* Return         : None
*******************************************************************************/
void NVIC_Configuration(void)
{
#ifdef  VECT_TAB_RAM  
  /* Set the Vector Table base location at 0x20000000 */
  NVIC_SetVectorTable(NVIC_VectTab_RAM, 0x0);
#else  /* VECT_TAB_FLASH  */
  /* Set the Vector Table base location at 0x08000000 */
  NVIC_SetVectorTable(NVIC_VectTab_FLASH, 0x0);   
#endif
}
/*******************************************************************************
* Function Name  : Delay
* Description    : Inserts a delay time.
* Input          : nCount: specifies the delay time length.
* Output         : None
* Return         : None
*******************************************************************************/
void Delay(vu32 nCount)
{
  for(; nCount != 0; nCount--);
}
#ifdef  DEBUG
/*******************************************************************************
* Function Name  : assert_failed
* Description    : Reports the name of the source file and the source line number
*                  where the assert_param error has occurred.
* Input          : - file: pointer to the source file name
*                  - line: assert_param error line source number
* Output         : None
* Return         : None
*******************************************************************************/
void assert_failed(u8* file, u32 line)
{
  /* User can add his own implementation to report the file name and line number,
     ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
  /* Infinite loop */
  while (1)
  {
  }
}
#endif
/******************* (C) COPYRIGHT 2008 STMicroelectronics *****END OF FILE****/
沙发
IJK| | 2010-12-11 15:44 | 只看该作者
貌似用万用表来测正弦波欠 妥:因为正弦波的频率可能比较高,最好用示波器来看。如果只有万用表,也能测,方法就是更改正弦波表格的那些值:都改成0(4095),万用表应该测得0V(Vdd)。

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板凳
wonderfully|  楼主 | 2010-12-11 16:39 | 只看该作者
恩,的确只有万用表。就是频率原因,按照你的方法试用了几个值,可以看到不同值了。

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地板
mcu520| | 2010-12-22 11:08 | 只看该作者
mark

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5
selina1983| | 2011-1-10 21:57 | 只看该作者
mark

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6
f19880301| | 2014-4-10 14:40 | 只看该作者
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