CCS/MSP432P401R: MSP432P401R UART

If local loopback is succeeding, but sending to another unit is failing, the first guess is that your bit-rate isn't right. (For local loopback, the bit-rate is always "correct".)

The usual suspects then are (1) the clock you're using (SMCLK?) isn't what you think it is, or (b) your divider isn't right.

If you show us your initialization code, someone might be able to see what the trouble is.

int main(void)
{
    // Hold the watchdog

    volatile uint32_t i;

    WDT_A->CTL = WDT_A_CTL_PW | WDT_A_CTL_HOLD;


    P1->DIR = ~(uint8_t) BIT1;
    P1->DIR |= BIT0 ;
    //P1->OUT &= ~BIT0 ;
    P1->OUT |= 0 ;
    P1->OUT = BIT1;
    //P1->REN = BIT1;                         // Enable pull-up resistor (P1.1 output high)
    P3->SEL0 |= BIT2 | BIT3;
    P3->SEL1 = 0;
    //P1->IES = BIT1;                         // Interrupt on high-to-low transition
    //P1->IFG = 0;                            // Clear all P1 interrupt flags
    //P1->IE = BIT1;                          // Enable interrupt for P1.1

    EUSCI_A2->CTLW0 |= EUSCI_A_CTLW0_SWRST; // Put eUSCI in reset
    EUSCI_A2->CTLW0 = EUSCI_A_CTLW0_SWRST | // Remain eUSCI in reset
            EUSCI_B_CTLW0_SSEL__SMCLK;      // Configure eUSCI clock source for SMCLK
    // Baud Rate calculation
    EUSCI_A2->BRW = 1;                      // Using baud rate calculator
    EUSCI_A2->MCTLW = (10 << EUSCI_A_MCTLW_BRF_OFS) |
            EUSCI_A_MCTLW_OS16;
    EUSCI_A2->CTLW0 &= ~EUSCI_A_CTLW0_SWRST;// Initialize eUSCI
    EUSCI_A2->IE |= EUSCI_A_IE_RXIE;        // Enable USCI_A0 RX interrupt

    // Enable Port 1 interrupt on the NVIC
    //NVIC->ISER[1] = 1 << ((PORT1_IRQn) & 31);
    NVIC->ISER[0] = 1 << ((EUSCIA2_IRQn) & 31);

    // Configure Port J
    PJ->DIR |= (BIT0| BIT1 | BIT2 | BIT3);
    PJ->OUT &= ~(BIT0 | BIT1 | BIT2 | BIT3);

    // Enable PCM rude mode, which allows to device to enter LPM3 without waiting for peripherals
    //PCM->CTL1 = PCM_CTL0_KEY_VAL | PCM_CTL1_FORCE_LPM_ENTRY;

    // Enable global interrupt
    __enable_irq();

    // Setting the sleep deep bit
    //SCB->SCR |= (SCB_SCR_SLEEPDEEP_Msk);

    SCB->SCR &= ~SCB_SCR_SLEEPONEXIT_Msk;   // Wake up on exit from ISR

    // Do not wake up on exit from ISR
    //SCB->SCR |= SCB_SCR_SLEEPONEXIT_Msk;

    // Ensures SLEEPONEXIT takes effect immediately
    __DSB();

    // Go to LPM4
    __sleep();
    while(1)
    {
    }
    }

int main(void)
{
    volatile uint32_t i;

    WDT_A->CTL = WDT_A_CTL_PW |             // Stop watchdog timer
            WDT_A_CTL_HOLD;

    P2->DIR |= BIT2;
    P2->OUT &= ~BIT2;                       // P1.0 outout low

    // Configure UART pins
    P3->SEL0 |= BIT2 | BIT3;                // set 2-UART pin as second function

    // Configure UART
    EUSCI_A2->CTLW0 |= EUSCI_A_CTLW0_SWRST; // Put eUSCI in reset
    EUSCI_A2->CTLW0 = EUSCI_A_CTLW0_SWRST | // Remain eUSCI in reset
            EUSCI_B_CTLW0_SSEL__SMCLK;      // Configure eUSCI clock source for SMCLK
    // Baud Rate calculation
    EUSCI_A2->BRW = 1;                      // Using baud rate calculator
    EUSCI_A2->MCTLW = (10 << EUSCI_A_MCTLW_BRF_OFS) |
            EUSCI_A_MCTLW_OS16;
    EUSCI_A2->CTLW0 &= ~EUSCI_A_CTLW0_SWRST;// Initialize eUSCI
    EUSCI_A2->IE |= EUSCI_A_IE_RXIE;        // Enable USCI_A0 RX interrupt

    SCB->SCR &= ~SCB_SCR_SLEEPONEXIT_Msk;   // Wake up on exit from ISR

    // Enable global interrupt
    __enable_irq();

    // Enable eUSCIA0 interrupt in NVIC module
    NVIC->ISER[0] = 1 << ((EUSCIA2_IRQn) & 31);

    while (1)
    {
//        // Arbitrary delay between each transmit to observe the
//        // characters being transmitted through a scope
//        for (i = 10; i > 0; i--);
//
//        while(!(EUSCI_A2->IFG & EUSCI_A_IFG_TXIFG));
//        EUSCI_A2->TXBUF = TXData;           // Load data onto buffer
//
//        __sleep();
    }
}

I have attached two codes, the first one is the transmitter UART configuration, and the second one the receiver one.

I'm not sure I see how the transmitter (first entry) ever transmits anything, since it doesn't enable EUSCI_A_IE_TXIE and there's nothing inline. Is this the code you used for local loopback?

Also, I have to ask: Did you remember to cross-connect (TXD->RXD in each direction) the pins between the Launchpads?

I think you're running the UART at 3Mbps, which is pretty fast if you have long-ish cables. You might try slowing it down a little.

I am using the BOOSTXL-AUDIO Boosterpack for voice recognition. In my program whenever a voice is recognized it starts to transmit through UART. I did not cross-connect because I have to use PIN 3.2 and PIN 3.3 as the other pins on the top are being covered by the same BoosterPack.

                                     Audio_stopCollect(Audio);
                                     recognizeState.ledCount = 0;
                                     Leds_off1();
                                     //Leds_setColor2(0, 0, 255);
                                     while(!(EUSCI_A2->IFG & EUSCI_A_IFG_TXIFG));
                                     EUSCI_A2->TXBUF = TranData;           //TranData is the integer I want to send
                                         

I was able to make it work. You were right the SMCLK was being divided by 16, so I change the multiplier. Thanks a lot!