新手求助，我想用DMA控制PWM占空比以控制舵机转动，在占空比减少的情况下没有问题，可是在占空比累加的情况下只会输出最后一个数据，增加每两个数据之间的差值情况会有所好转，但是还是会存在一定问题，请问是什么原因？

测试数据：
累加：300,309,319,328,338,348,357,367,376,386,396,405,415,424,434,444,453,463,472,482,492,501,511,520,530,540,549,559,568,578,588,597,607,616,626,636,645,655,664,674,684,693,703,712,722,732,741,751,760,770,

累减：780,770,760,751,741,732,722,712,703,693,684,674,664,655,645,636,626,616,607,597,588,578,568,559,549,540,530,520,511,501,492,482,472,463,453,444,434,424,415,405,396,386,376,367,357,348,338,328,319,309,

程序配置：
DMA_Config(uint_16t* action_buf, uint_16t action_size) {
  RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, input_state);

  DMA_InitTypeDef DMA_InitStructure;
  DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)action_buf;
  DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralDST;
  DMA_InitStructure.DMA_BufferSize = action_size;
  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_Normal;
  DMA_InitStructure.DMA_Priority = DMA_Priority_Medium;
  DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
  DMA_InitStructure.DMA_PeripheralBaseAddr = TIM1_BASE + 0x34;
  DMA_Init(DMA1_Channel3, &DMA_InitStructure);
  DMA_ITConfig(DMA1_Channel3, DMA_IT_TC, ENABLE);
  TIM_DMACmd(TIM1, TIM_DMA_CC1, ENABLE);
  DMA_Cmd(DMA1_Channel3, ENABLE);
}

                                 

jackten 发表于 2016-12-23 11:15

大神有遇到过吗这种问题吗？

配置有问题吧？

ts2000 发表于 2016-12-23 11:24
配置有问题吧？

主要在传输数据递减的情况下是正常的，累加的情况下会出现直接传输最后一个数据的情况。我用示波器看了下，占空比在数据累加的情况下也是直接跳转到最后一个数据的占空比。

累加和累减的程序看一下

肯定程序有问题

五哥1 发表于 2016-12-23 23:26
累加和累减的程序看一下

大神，上传了DMA配置，你看看有没有什么问题，数据的话是那个数组直接传输。

shuolang126 发表于 2016-12-24 08:15
肯定程序有问题

大神，上传了部分程序，你看看有没有错误

程序不完整，缺少TIM的初始化代码！input_state状态不明

官方例程，供你参考！
/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
#define TIM1_CCR3_Address    0x40012C3C

/* Private macro -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
TIM_OCInitTypeDef  TIM_OCInitStructure;
uint16_t SRC_Buffer[3] = {0, 0, 0};
uint16_t TimerPeriod = 0;

/* Private function prototypes -----------------------------------------------*/
void RCC_Configuration(void);
void GPIO_Configuration(void);
void DMA_Configuration(void);

/* Private functions ---------------------------------------------------------*/

/**
  * @brief  Main program
  * @param  None
  * @retval None
  */
int main(void)
{
  /*!< At this stage the microcontroller clock setting is already configured,
       this is done through SystemInit() function which is called from startup
       file (startup_stm32f10x_xx.s) before to branch to application main.
       To reconfigure the default setting of SystemInit() function, refer to
       system_stm32f10x.c file
     */     
      
  /* System Clocks Configuration */
  RCC_Configuration();

  /* GPIO Configuration */
  GPIO_Configuration();

  /* DMA Configuration */
  DMA_Configuration();

  /* TIM1 DMA Transfer example -------------------------------------------------
  TIM1CLK = SystemCoreClock, Prescaler = 0, TIM1 counter clock = SystemCoreClock
  SystemCoreClock is set to 72 MHz for Low-density, Medium-density, High-density
  and Connectivity line devices and to 24 MHz for Low-Density Value line and
  Medium-Density Value line devices.

  The objective is to configure TIM1 channel 3 to generate complementary PWM
  signal with a frequency equal to 17.57 KHz:
     - TIM1_Period = (SystemCoreClock / 17570) - 1
  and a variable duty cycle that is changed by the DMA after a specific number of
  Update DMA request.

  The number of this repetitive requests is defined by the TIM1 Repetition counter,
  each 3 Update Requests, the TIM1 Channel 3 Duty Cycle changes to the next new
  value defined by the SRC_Buffer .
  -----------------------------------------------------------------------------*/
  /* Compute the value to be set in ARR register to generate signal frequency at 17.57 Khz */
  TimerPeriod = (SystemCoreClock / 17570 ) - 1;
  /* Compute CCR1 value to generate a duty cycle at 50% */
  SRC_Buffer[0] = (uint16_t) (((uint32_t) 5 * (TimerPeriod - 1)) / 10);
  /* Compute CCR1 value to generate a duty cycle at 37.5% */
  SRC_Buffer[1] = (uint16_t) (((uint32_t) 375 * (TimerPeriod - 1)) / 1000);
  /* Compute CCR1 value to generate a duty cycle at 25% */
  SRC_Buffer[2] = (uint16_t) (((uint32_t) 25 * (TimerPeriod - 1)) / 100);

  /* TIM1 Peripheral Configuration --------------------------------------------*/
  /* Time Base configuration */
  TIM_TimeBaseStructure.TIM_Prescaler = 0;
  TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
  TIM_TimeBaseStructure.TIM_Period = TimerPeriod;
  TIM_TimeBaseStructure.TIM_ClockDivision = 0;
  TIM_TimeBaseStructure.TIM_RepetitionCounter = 2;

  TIM_TimeBaseInit(TIM1, &TIM_TimeBaseStructure);

  /* Channel 3 Configuration in PWM mode */
  TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2;
  TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
  TIM_OCInitStructure.TIM_OutputNState = TIM_OutputNState_Enable;
  TIM_OCInitStructure.TIM_Pulse = SRC_Buffer[0];
  TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low;
  TIM_OCInitStructure.TIM_OCNPolarity = TIM_OCNPolarity_Low;
  TIM_OCInitStructure.TIM_OCIdleState = TIM_OCIdleState_Set;
  TIM_OCInitStructure.TIM_OCNIdleState = TIM_OCIdleState_Reset;

  TIM_OC3Init(TIM1, &TIM_OCInitStructure);

  /* TIM1 Update DMA Request enable */
  TIM_DMACmd(TIM1, TIM_DMA_Update, ENABLE);

  /* TIM1 counter enable */
  TIM_Cmd(TIM1, ENABLE);

  /* Main Output Enable */
  TIM_CtrlPWMOutputs(TIM1, ENABLE);

  while (1)
  {}
}

/**
  * @brief  Configures the different system clocks.
  * @param  None
  * @retval None
  */
void RCC_Configuration(void)
{
  /* TIM1, GPIOA and GPIOB clock enable */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1 | RCC_APB2Periph_GPIOA |
                         RCC_APB2Periph_GPIOB, ENABLE);
  /* DMA clock enable */
  RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);
}

/**
  * @brief  Configure the TIM1 Pins.
  * @param  None
  * @retval None
  */
void GPIO_Configuration(void)
{
  GPIO_InitTypeDef GPIO_InitStructure;

  /* GPIOA Configuration: Channel 3 as alternate function push-pull */
  GPIO_InitStructure.GPIO_Pin =  GPIO_Pin_10;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_Init(GPIOA, &GPIO_InitStructure);

  /* GPIOB Configuration: Channel 3N as alternate function push-pull */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_15;
  GPIO_Init(GPIOB, &GPIO_InitStructure);
}

/**
  * @brief  Configures the DMA.
  * @param  None
  * @retval None
  */
void DMA_Configuration(void)
{
  DMA_InitTypeDef DMA_InitStructure;

  /* DMA1 Channel5 Config */
  DMA_DeInit(DMA1_Channel5);

  DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)TIM1_CCR3_Address;
  DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)SRC_Buffer;
  DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralDST;
  DMA_InitStructure.DMA_BufferSize = 3;
  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_Priority = DMA_Priority_High;
  DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;

  DMA_Init(DMA1_Channel5, &DMA_InitStructure);

  /* DMA1 Channel5 enable */
  DMA_Cmd(DMA1_Channel5, ENABLE);
}

官方提供了很多外设的使用例程，多看看还是有帮助的

累加和累减的程序看一下