CC2650STK: UART CallBack mode

Hi, i need help with UART. 

UART_write() performs every 1 second by the timer. UART_read() in CallBack mode and it's triggering after each UART_write(), I don't understand why.
UART_read() must work independently from UART_write(). 

I tried using different arrays for reading and writing, it did't work.

Any help is appreciated. 

void some_func()
{

}

void readCallback(UART_Handle Uhandle, void *rxBuf, size_t size)
 {
    Event_post(eventH, UART_RX_COMPLETE);
 }

void clock_cb(UArg arg)
{
    Event_post(eventH, TIMER);
}

void taskFxn(UArg arg0, UArg arg1)
{
    eventH = Event_create(NULL, NULL);

    UART_Params_init(&Uparams);
    Uparams.writeDataMode  = UART_DATA_TEXT;
    Uparams.readDataMode  = UART_DATA_TEXT;
    Uparams.readMode          = UART_MODE_CALLBACK;
    Uparams.readEcho           = UART_ECHO_OFF;
    Uparams.readCallback      = readCallback;
    Uparams.baudRate           = 9600;
    Uhandle = UART_open(0, &Uparams);
    UART_control(Uhandle, UARTCC26XX_CMD_RETURN_PARTIAL_ENABLE, NULL);

    UART_read(Uhandle, buff, 10);


    Clock_Params_init(&clockParams);
    clockParams.arg = (UArg)eventH;
    clockParams.startFlag = 0;
    clockH = Clock_create((Clock_FuncPtr) &clock_cb, 100000, &clockParams, NULL);
    Clock_start(clockH);


    uint8_t counter = 0x0;
    uint16_t events;

    while(true)
    {
        events = Event_pend(eventH, Event_Id_NONE, 0xFFFFFFFF, BIOS_WAIT_FOREVER);

        if (events & UART_RX_COMPLETE)
        {
            some_func();
            Task_sleep (10000);
            UART_read(Uhandle, buff, 10);
        }

        if (events & TIMER)
        {
            counter++;
            buff[0] = counter;

            UART_write(Uhandle, buff, 1);
            Task_sleep (10000);
            Clock_start (clockH);
        }

    }
}

Kind Regards, Egor