MSP430F6736A UART configuration via Code Composer

Using embedded proggraming, Code Composer Studio 6.0.1,

Trying to configurate UART to communicate between MSP430F6736A and my PC. Using USB/RS485 converver(2 vire (A,B)).

For sending data using HERCULES(app for testing communication).

         #include <msp430.h> 
            #include <msp430f6736.h>
            /*
             * main.c
             */

            int main(void) {

                WDTCTL = WDTPW | WDTHOLD;   // Stop watchdog timer

                P4DIR |= BIT6;
                        P4OUT &= ~BIT6;
                    //clock
                //UCSCTL0 |= DCO_0 | MOD_0;
                //UCSCTL1 |= DCORSEL_0;

                // Config pinov  P2.2 a P2.3 na ich funkciu(Rx a Tx)
                P2SEL |= BIT2 + BIT3; // RX and TX pins

                // config comm
                UCA1CTLW0 |= UCSWRST; // reset UCA1 for config
                UCA1CTLW0 |= UCSSEL_1 ; //  ACLK as source clock
                UCA1MCTLW |= UCBRS0;

                // Baudrate from datasheet
                UCA1BR0 = 1;    // 1200 Baud
                UCA1BR1 = 11;   // 1200 Baud

                UCA1CTLW0 &= ~UCSWRST; // UCA1 back from  reset

                // interrupts enabled for RT and TX
                UCA1IE |= UCTXIE | UCTXIE;

                __bis_SR_register(GIE); // global interupt enabled

            }

#pragma vector=USCI_A1_VECTOR
__interrupt void    Recieve_ISR(void)
{
    while  (!UCA1IFG)    //  USCI_A0 TX  buffer  ready?
    {
    P4DIR |= BIT6;
    P4OUT &= ~BIT6;
    UCA1RXBUF  =  UCA1TXBUF;    //  TX  -&amp;gt;   RXed    character
    }
}

All I want is when I send data(for eample number 5) from HERCULES(config same: 1200 baud, no parity, 1 stop bit) I want to receive them and turn LED on. But it doesn´t work.

Somewhere in this code is something missing or something bad written. , . I got big head from datasheets so can anyone help me?