RCC_APB2PeriphClockCmd(AM2302_RCC, ENABLE);

    GPIO_InitStructure.GPIO_Pin = AM2302_PIN;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_10MHz;
    GPIO_Init(AM2302_GPIO_PORT, &GPIO_InitStructure);

    RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);

    DMA_DeInit(DMA1_Channel7);
    DMA_StructInit(&DMA_InitStructure);
    DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)(&TIM2->CCR1);
    DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)&DeltaBuffer[0];
    DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;
    DMA_InitStructure.DMA_BufferSize = DELTA_SAMPLES;
    DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
    DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
    DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord; // 16-bit
    DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;
    DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;
    DMA_InitStructure.DMA_Priority = DMA_Priority_High;
    DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
    DMA_Init(DMA1_Channel7, &DMA_InitStructure);

    
    /* TIM2 clock enable */
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2,ENABLE);

    TIM_Cmd(TIM2, DISABLE);
    
    TIM_TimeBaseStructInit(&TIM_TimeBaseStructure);
    TIM_TimeBaseStructure.TIM_Prescaler = 0;
    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseStructure.TIM_Period = 0xFFFF;
    TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);
    
    TIM_SetCounter(TIM2,0);

    /* Channel configuration */
    TIM_ICInitStructure.TIM_Channel = TIM_Channel_2;
    TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Falling;
    TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI;
    TIM_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1;
    TIM_ICInitStructure.TIM_ICFilter = 0x04;
    TIM_PWMIConfig(TIM2, &TIM_ICInitStructure);

    TIM_SelectInputTrigger(TIM2, TIM_TS_TI2FP2);
    TIM_SelectSlaveMode(TIM2, TIM_SlaveMode_Reset);
    TIM_SelectMasterSlaveMode(TIM2, TIM_MasterSlaveMode_Enable);

    
    memset((void *)&DeltaBuffer, 0, DELTA_SAMPLES);
        
    //Data request from AM2302
    GPIO_InitStructure.GPIO_Pin = AM2302_PIN;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_10MHz;
    GPIO_Init(AM2302_GPIO_PORT, &GPIO_InitStructure);
    
    GPIO_ResetBits(AM2302_GPIO_PORT, AM2302_PIN);
    
    delay10us(100);


    TIM_Cmd(TIM2, ENABLE);
    DMA_Cmd(DMA1_Channel7, ENABLE);    

    //Waiting for data
    GPIO_InitStructure.GPIO_Pin = AM2302_PIN;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_10MHz;
    GPIO_Init(AM2302_GPIO_PORT, &GPIO_InitStructure);
    
    delay10us(50000);