input capture _ DMA request

Posted on August 25, 2015 at 15:59

Hi,

Please i have to capture an input signal  and read it's frequency value with a DMA request but i can't find any ressources.

I know the other solution with interreupt but i insist on this method with DMA, i need it.

i did the configuration required but the buffer of destination shows always value=0 !

here is my code:

uint32_t TIM1CapturedValue_u32[2];

void CaptureDMA(void)

{

  DMA_DeInit(DMA1_Channel2);                                            //    Time1_ch1<-->DMA1_ch2          

  

  DMA_InitStructure.DMA_PeripheralBaseAddr = TIM_DMABase_CCR1;          //    Time1-->CCR1        

  DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)TIM1CapturedValue_u32[0];

  DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;

  DMA_InitStructure.DMA_BufferSize =2;

  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_Channel2, &DMA_InitStructure);

  

  //Enable DMA1 channel2 

  DMA_Cmd(DMA1_Channel2, ENABLE);  

  

  

   TIM_TimeBaseStructure.TIM_Prescaler = 0; // Counter Clk = 72M

   TIM_TimeBaseStructure.TIM_Period = 0XFFFF;

   TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;

   TIM_TimeBaseInit(TIM1, &TIM_TimeBaseStructure);

    

   TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising;

   TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI;

   TIM_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1; 

   TIM_ICInitStructure.TIM_ICFilter = 0x00;

   TIM_ICInitStructure.TIM_Channel = TIM_Channel_1; 

   TIM_ICInit(TIM1, &TIM_ICInitStructure); 

    

   /* Enable the TIMER CAPTURE DMA requests */

TIM_SelectCCDMA(TIM1, ENABLE);

TIM_DMACmd(TIM1, TIM_DMA_CC1, ENABLE);   

    

    // TIM1 enable counter 

    TIM_Cmd(TIM1,ENABLE); 

}