使用DMA的STM32F3 DAC信號生成

Question

我正在STM32f3Discovery板上編寫一個程序，該程序應該使用DAC生成正弦波。 我有幾個文件，在下面列出。

Utilities.h：

#ifndef UTILITIES_H
#define UTILITIES_H

/** @brief Configure GPIOE, pin 9 (LED) as output PP
 */
void GPIOE_init( void );

/** @brief Configure Timer 2, event frequency - 100Hz
 */
void Timer_init( void );

/** @brief Configure interrupt handler
 */
void NVIC_config( void );

/** @brief Configure and enable DAC channel 1 on pin PA4,
 *  with TIM2 TRGO as trigger
 */
void DACch1_config( void );

/** @brief Configure DMA to work with DAC
 */
void DMA_config( void );

#endif //UTILITIES_H

實用工具：

#include "utilities.h"
#include "stm32f30x.h"

const uint16_t sineWave12bit[32] = {
        2048,2447,2831,3185,3495,3750,3939,4056,
        4095,4056,3939,3750,3495,3185,2831,2447,
        2048,1648,1264,910,600,345,156,39,
        0,39,156,345,600,910,1264,1648 };

//This address is taken from reference manual for stm32f30
//See pages 53 and 439
#define DAC_DHR12RD_ADDRESS 0x40007420

void Timer_init( void ){

    /* Configuring frequency of timer, thus sinus frequency */
    /* Keep in mind, that system clock is set to 80Mhz */
    TIM_TimeBaseInitTypeDef    timer2;

    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);

    TIM_TimeBaseStructInit( &timer2 );
    timer2.TIM_CounterMode = TIM_CounterMode_Up;
    //Setting prescaler so that timer clock will be only 10000Hz
    timer2.TIM_Prescaler = 8000 - 1;
    //Setting period so Timer will give signal of frequency 100Hz
    timer2.TIM_Period = 100 - 1;
    TIM_TimeBaseInit( TIM2, &timer2 );

    //generate event when counter hits TIM_period value
    TIM_SelectOutputTrigger(TIM2, TIM_TRGOSource_Update);

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

void NVIC_config( void ){
    NVIC_InitTypeDef nvic;

    nvic.NVIC_IRQChannel = TIM2_IRQn;
    nvic.NVIC_IRQChannelPreemptionPriority = 0;
    nvic.NVIC_IRQChannelSubPriority = 0;
    nvic.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init( &nvic );
}


void GPIOE_init( void ){
    /* GPIOE initialization */
    GPIO_InitTypeDef        leds;

    RCC_AHBPeriphClockCmd( RCC_AHBPeriph_GPIOE, ENABLE );

    leds.GPIO_Pin = GPIO_Pin_9;
    leds.GPIO_Mode = GPIO_Mode_OUT;
    leds.GPIO_OType = GPIO_OType_PP;
    leds.GPIO_Speed = GPIO_Speed_50MHz;
    leds.GPIO_PuPd = GPIO_PuPd_NOPULL;
    GPIO_Init(GPIOE, &leds);
}

void DACch1_config( void ){
      /*******THERE IS ONLY ONE DAC ON STM32F30!!!!!!!!!!!!!!!!!!******************/
      DAC_InitTypeDef   DACch1;
      GPIO_InitTypeDef  DACch1_out;

      /* Enable GPIOA Periph clock */
      RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA, ENABLE);

      /* Configure PA04 as analog  */
      DACch1_out.GPIO_Pin =  GPIO_Pin_4;
      DACch1_out.GPIO_Mode = GPIO_Mode_AN;
      DACch1_out.GPIO_OType = GPIO_OType_PP;
      DACch1_out.GPIO_PuPd = GPIO_PuPd_NOPULL;
      DACch1_out.GPIO_Speed = GPIO_Speed_50MHz;
      GPIO_Init(GPIOA, &DACch1_out);

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

      /* Init the DAC_Init structure */
      DAC_StructInit(&DACch1);

      /* Configure DAC */
      DACch1.DAC_Trigger = DAC_Trigger_T2_TRGO;
      DACch1.DAC_WaveGeneration = DAC_WaveGeneration_None;
      DACch1.DAC_LFSRUnmask_TriangleAmplitude = DAC_LFSRUnmask_Bits2_0;
      DACch1.DAC_OutputBuffer = DAC_OutputBuffer_Disable;

      /* DAC channel 1 configuration*/
      DAC_Init( DAC_Channel_1, &DACch1 );

      /* Enable DAC channel 1       */
      DAC_Cmd( DAC_Channel_1, ENABLE);
}


void DMA_config( void ){
    DMA_InitTypeDef mem2DAC;

    /* Enable clock for DMA1 */
    RCC_AHBPeriphClockCmd( RCC_AHBPeriph_DMA1, ENABLE );

    /* Reset DMA1 channel 1 register values to default */
    DMA_DeInit(DMA1_Channel1);

    //Specify destination address
    mem2DAC.DMA_PeripheralBaseAddr = DAC_DHR12RD_ADDRESS;
    //Specify source address - LUT for sine
    mem2DAC.DMA_MemoryBaseAddr = (uint32_t) &sineWave12bit;
    //Set Peripheral as destination
    mem2DAC.DMA_DIR = DMA_DIR_PeripheralDST;
    mem2DAC.DMA_BufferSize = 32;
    mem2DAC.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
    mem2DAC.DMA_MemoryInc = DMA_MemoryInc_Enable;
    mem2DAC.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Word;
    mem2DAC.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;
    mem2DAC.DMA_Mode = DMA_Mode_Circular;
    mem2DAC.DMA_Priority = DMA_Priority_High;
    mem2DAC.DMA_M2M = DMA_M2M_Disable;

    DMA_Init( DMA1_Channel1, &mem2DAC );

    /* Enable DMA1 Channel1 */
    DMA_Cmd( DMA1_Channel1, ENABLE );

    /* Enable DMA fo DAC channel 1*/
    DAC_DMACmd( DAC_Channel_1, ENABLE );

}

main.c：

/**
  ******************************************************************************
  * @file    main.c
  * @author  Ac6
  * @version V1.0
  * @date    01-December-2013
  * @brief   Default main function.
  ******************************************************************************
*/


#include "stm32f30x.h"
#include "utilities.h"

int main(void)
{
    DMA_config();

    DACch1_config();

    Timer_init();

    while(1){

    }
}

因此，從理論上講，它應該在引腳A.04上生成正弦波。 但是，當我使用示波器查看此引腳上的電壓時，它什么也沒顯示（地電位）。

有人知道什么地方可能出問題嗎？

Answer 1

好吧，我修復了它。 如果其他人有興趣，似乎可以驅動DAC_1的唯一合適的DMA通道是DMA2通道3。可以以某種方式將其重新映射到DMA1通道3，但仍在困擾着它。

編輯：

一切正常。 如果對某人有幫助，請按照以下所有必要步驟操作，以使DAC在STM32f3上正常運行：

1. 啟用timerX的時鍾（必須查看哪些計時器可用於通過TRGO事件觸發DAC），DMA，DAC和GPIOA。 如果要將非默認DMA用於DAC，請為SYSCFG啟用時鍾。

2. 設置所需的DAC通道。 請注意，在STM32f3 Discovery上，只有1個具有2個通道的DAC。 DACch1輸出為PA4，DACch2輸出為PA5。

3. 將選定的GPIOA配置為模擬輸入和初始化。

4. 配置DAC和初始化。 請記住為DAC啟用DMA。

5. 如果要更改與DAC一起使用的DMA的默認設置，請使用SYSCFG_DMAChannelRemapConfig命令。

6. 配置DMA和初始化。

7. 配置所需的計時器和初始化。 記住要設置TRGO中斷！

下面，我包括使用非默認DMA在DACch1上生成正弦波的工作代碼。

#include "utilities.h"
#include "stm32f30x.h"

const uint16_t sineWave12bit[64] = {
        2048,2248,2447,2642,2831,3013,3185,3346,
        3495,3630,3750,3853,3939,4007,4056,4085,
        4095,4085,4056,4007,3939,3853,3750,3630,
        3495,3346,3185,3013,2831,2642,2447,2248,
        2048,1847,1648,1453,1264,1082,910,749,
        600,465,345,242,156,88,39,10,
        0,10,39,88,156,242,345,465,
        600,749,910,1082,1264,1453,1648,1847 };

//This address is taken from reference manual for stm32f30
//See pages 53 and 439
#define DAC_DHR12R1_ADDRESS 0x40007408

void Timer_init( void ){

    /* Configuring frequency of timer, thus sinus frequency */
    /* Keep in mind, that system clock is set to 80Mhz */
    TIM_TimeBaseInitTypeDef    timer2;

    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);

    TIM_TimeBaseStructInit( &timer2 );
    timer2.TIM_CounterMode = TIM_CounterMode_Up;
    //Setting prescaler so that timer clock will be only 10000Hz
    timer2.TIM_Prescaler = 8000 - 1;
    //Setting period so Timer will give signal of frequency 1000Hz
    timer2.TIM_Period = 10 - 1;
    TIM_TimeBaseInit( TIM2, &timer2 );

    //generate event when counter hits TIM_period value
    TIM_SelectOutputTrigger(TIM2, TIM_TRGOSource_Update);

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

void NVIC_config( void ){
    NVIC_InitTypeDef nvic;

    nvic.NVIC_IRQChannel = TIM2_IRQn;
    nvic.NVIC_IRQChannelPreemptionPriority = 0;
    nvic.NVIC_IRQChannelSubPriority = 0;
    nvic.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init( &nvic );
}


void GPIOE_init( void ){
    /* GPIOE initialization */
    GPIO_InitTypeDef        leds;

    RCC_AHBPeriphClockCmd( RCC_AHBPeriph_GPIOE, ENABLE );

    leds.GPIO_Pin = GPIO_Pin_9;
    leds.GPIO_Mode = GPIO_Mode_OUT;
    leds.GPIO_OType = GPIO_OType_PP;
    leds.GPIO_Speed = GPIO_Speed_50MHz;
    leds.GPIO_PuPd = GPIO_PuPd_NOPULL;
    GPIO_Init(GPIOE, &leds);
}

void DACch1_config( void ){
      /*******THERE IS ONLY ONE DAC ON STM32F30!!!!!!!!!!!!!!!!!!******************/
      DAC_InitTypeDef   DACch1;
      GPIO_InitTypeDef  DACch1_out;

      /* Enable GPIOA Periph clock */
      RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA, ENABLE);

      /* Configure PA04 as analog  */
      DACch1_out.GPIO_Pin =  GPIO_Pin_4;
      DACch1_out.GPIO_Mode = GPIO_Mode_AN;
      DACch1_out.GPIO_PuPd = GPIO_PuPd_NOPULL;
      GPIO_Init(GPIOA, &DACch1_out);

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

      /* Init the DAC_Init structure */
      DAC_StructInit(&DACch1);

      /* Reset DAC configuration */
      DAC_DeInit();

      /* Configure DAC */
      DACch1.DAC_Trigger = DAC_Trigger_T2_TRGO;
      DACch1.DAC_WaveGeneration = DAC_WaveGeneration_None;
      DACch1.DAC_LFSRUnmask_TriangleAmplitude = DAC_LFSRUnmask_Bits2_0;
      DACch1.DAC_OutputBuffer = DAC_OutputBuffer_Enable;

      /* DAC channel 1 configuration*/
      DAC_Init( DAC_Channel_1, &DACch1 );

      /* Enable DAC channel 1       */
      DAC_Cmd( DAC_Channel_1, ENABLE);
}


void DMA_config( void ){
    DMA_InitTypeDef mem2DAC;

    /* Enable clock for SYSCFG in order to change DMA for DAC from
     * DMA2 channel3 to DMA1 channel 3 (default is DMA2 channel 3) */
    RCC_APB2PeriphClockCmd( RCC_APB2Periph_SYSCFG, ENABLE );

    /* Use DMA1 channel 3 for DAC1 */
    SYSCFG_DMAChannelRemapConfig( SYSCFG_DMARemap_TIM6DAC1, ENABLE );

    /* Enable clock for DMA1 */
    RCC_AHBPeriphClockCmd( RCC_AHBPeriph_DMA1, ENABLE );

    /* Reset DMA1 channel 1 register values to default */
    DMA_DeInit( DMA1_Channel3 );

    mem2DAC.DMA_PeripheralBaseAddr = DAC_DHR12R1_ADDRESS;
    mem2DAC.DMA_MemoryBaseAddr = (uint32_t)&sineWave12bit;
    mem2DAC.DMA_DIR = DMA_DIR_PeripheralDST;
    mem2DAC.DMA_BufferSize = 64;
    mem2DAC.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
    mem2DAC.DMA_MemoryInc = DMA_MemoryInc_Enable;
    mem2DAC.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord;
    mem2DAC.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;
    mem2DAC.DMA_Mode = DMA_Mode_Circular;
    mem2DAC.DMA_Priority = DMA_Priority_High;
    mem2DAC.DMA_M2M = DMA_M2M_Disable;

    DMA_Init( DMA1_Channel3, &mem2DAC );

    /* Enable DMA1 Channel1 */
    DMA_Cmd( DMA1_Channel3, ENABLE );

    /* Enable DMA fo DAC channel 1*/
    DAC_DMACmd( DAC_Channel_1, ENABLE );

}

Answer 2

我遇到了類似的問題。 首先檢查您的MCU是否具有DAC模塊。 可能沒有DAC外設，在這種情況下將不會產生正弦波。 您可以在數據手冊中針對您的特定微控制器封裝進行檢查。