void EP2_OUT_Callback(void)
{
    SetEPRxStatus(ENDP2, EP_RX_VALID);

    static portBASE_TYPE xHigherPriorityTaskWoken;
    xHigherPriorityTaskWoken = pdFALSE;
    xSemaphoreGiveFromISR(xSemaphoreUSB_EP2_OUT, &xHigherPriorityTaskWoken );
}

void prvUSB( void *pvParameters )
{
    uint8_t                answer[64];
    GPIO_InitTypeDef      GPIO_InitStructure;

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
    //Set PA11,12 as USB_DM,DP
    GPIO_InitStructure.GPIO_Pin =  GPIO_Pin_11 | GPIO_Pin_12;        // set DAC1 pin as analog output
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOA, &GPIO_InitStructure);

    xSemaphoreUSB_EP2_OUT = xSemaphoreCreateBinary();

    USB_Disconnect_Config();
    Set_USBClock();
    USB_Interrupts_Config();
    USB_Init();

    while(1)
    {
        if(xSemaphoreUSB_EP2_OUT != NULL)
        {
            if( xSemaphoreTake( xSemaphoreUSB_EP2_OUT, portMAX_DELAY  ) == pdTRUE )
            {
                // в answer получаем данные с хоста
                USB_SIL_Read(EP2_OUT, answer);

                // отправляем данные на хост
                USB_SIL_Write(EP1_IN, answer, 64);
                SetEPTxValid(ENDP1);
            }
        }
    }
}

// отправляем данные на хост
                USB_SIL_Write(EP1_IN, answer, 64);
                SetEPTxValid(ENDP1);