void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim3)
{

    if (!TIMER_ACT) {

        HAL_ADC_Start(&hadc1);
        HAL_ADC_PollForConversion(&hadc1,1000);

        adcResult = HAL_ADC_GetValue(&hadc1);
        t_buffer[0] = (uint8_t)((adcResult & 0xFF00) >> 8);
        t_buffer[1] = (uint8_t)(adcResult & 0x00FF);
        HAL_ADC_Stop(&hadc1);
        CDC_Transmit_FS(t_buffer, 2);
    } else {
        HAL_ADC_Start_DMA(&hadc1,(uint32_t*) &ADC_Data,DMA_BUF_SIZE);
    }
}