CCS/MSP430F5438A-EP: My UART communication code prints out nothing or '@' character with random time on the terminal

Tool/software: Code Composer Studio

Dear community members, 

Hi, I am a beginner of the TI board, MSP430F5438A, and now I am testing UART communication with UCA1, which is through USB.

I (thought I) configured out and set all the registers for the UART communication appropriately, so I launched the terminal that CCS provides with the settings I've made.

The settings I've made is written in the function 'halUsbInit()' which is in the code below, and I also have written some comments for you.

With the settings, I launched terminal with: Baud rate = 57600, Data bits =  7, Parity bits = NONE , Stop bits = 1, and Control Flow = NONE.

However, the problem is, the terminal prints out nothing when I run the code below, and the stranger thing is that it sometimes prints out '@' character!

Would you suggest me some cause or a solution for me?

What I have checked is:

UCA1TXBUF register and find it out that it stores the data I wanted finely.

Register value by printing them out on LCD to check if it was modified finely --> was OK.

Thank you very much for your time.

void halUsbInit(void)
{
unsigned char i;

for (i = 0; i < 255; i++)
   halUsbReceiveBuffer[i] = '\0';

bufferSize = 0;
USB_PORT_SEL |= USB_PIN_RXD + USB_PIN_TXD;
USB_PORT_DIR |= USB_PIN_TXD; // PORT_DIR(HI) : TXD
USB_PORT_DIR &= ~USB_PIN_RXD; // PORT_DIR(LO) : RXD

UCA1CTL1 |= 0x00//UCSWRST; //Reset State, UCSI_A1 Control 1, this op. modifies the lowest bit
UCA1CTL0 = UCMODE_0; // UCSI_A1 Control 0 = UCMODE_0; UCMODE_0 denotes UART mode
  // this mods. last 2nd, 3rd bits, can be modified only when UCSWRST=1, and seems to be UART mode since UCMODE_0 is 0x00 macro

UCA1CTL0 |= UC7BIT; // 7bit comm. , UCA1CTL0: UCSI_A1 control 0 --> 1: 7bits, 0: 8bits
UCA1CTL1 |= UCSSEL_2; //clock selection: SMCLK
//UCSSEL: MACRO FOR: 0x80 = 1000 0000 : Denotes SMCLK-------/
UCA1BR0 = 138; // 8Mhz/57600=138, UCAxBR0: USCI_Ax baud rate control 0,
UCA1BR1 = 0; // UCAxBR1: USCI_Ax baud rate control 1
  // BR0: low byte of clock & BR1: high byte of clock --> forms 16-bit val (UCAxBR0 + UCAxBR1 * 256)
  // for this case, that is 0000 0001 0001 0000

UCA1MCTL = 0xE; //14 -> 1110 : oversampling disabled, second modulation (111)
UCA1CTL1 &= ~UCSWRST; // RESET mode OFF
UCA1IE |= 0x01; // RECIEVE interrupt enabled

__bis_SR_register(GIE); // Enable Interrupts
__no_operation();

}

void halUsbShutDown(void)
{
UCA1IE &= ~UCRXIE; // Disable back RX interrupt
UCA1CTL1 = UCSWRST; //Reset State
USB_PORT_SEL &= ~(USB_PIN_RXD + USB_PIN_TXD); // get rid of the assigned RX, TX pins away
USB_PORT_DIR |= USB_PIN_TXD;
USB_PORT_DIR |= USB_PIN_RXD;
USB_PORT_OUT &= ~(USB_PIN_TXD + USB_PIN_RXD);
}

void halUsbSendChar(char* character,int i)
{
char* ERRC="LOOP ";
char* NEXTOPC ="PR ";

if(UCA1IFG & UCTXIFG)

   halLcdPrintLine(NEXTOPC, 5+i, 0);

while (!(UCA1IFG & UCTXIFG))
   {
      halLcdPrintLine(ERRC, 1, 0);
   }
    //UCA1IFG: interrupt flag register, UCTXIFG : 1 bit from UCA1IFG, 0: no interrupt, 1: interrupt
    // for this case, if two are the same -> get out of while, if diff-> in while loop forever, which means some undesired error happened

UCA1TXBUF = *character; //UCA1TXBUF: 8-bit register, stores a 8-bit char.
}

/**
* main.c
*/
int main(void)
{
WDTCTL = WDTPW | WDTHOLD; // stop watchdog timer
P1DIR |= BIT1;

char REG_BUF[15]={0,};

halLcdInit();
halLcdBackLightInit();
halLcdClearScreen();

halLcdBackLightInit();
halLcdClearScreen();
// halLcdPrintLine("Baudrate = 57600", 0, 0);
// halUsbInit();

int i;
char character[17]={'E', 'F', 0};
for (i =0 ; i < 3 ; i++)
{
  halUsbInit();

  halUsbSendChar( (character + i) , i);

  char buf[3]={0,}; 
  buf[0]=UCA1TXBUF;

  halLcdPrint(buf, 0);

  __delay_cycles(100000);

  halUsbShutDown();
  volatile unsigned int k;

  P1OUT ^= BIT1;

  k = 20000;
  do k--;
  while(k != 0);
}
//halUsbShutDown();

return 0;
}