MSP430FR5969: UART communication with USCIA1 not working

Part Number: MSP430FR5969

Hi everyone,

I'm using CCS composer and I want to communicate from the msp430FR5969 with the ESP8266 module through UART communication. Basically I want to send an AT command to the ESP8266 through the USCI_A1 interrupt in order to obtain an answer (OK) and send it to the serial monitor on my PC using the USCI_A0 module.

The problem is that the code never enters the interrupt of USCI_A1, but only the one of USCI_A0.

//***************************************************************************************
//  Sending data via UART: try to catch response to AT
//***************************************************************************************
//

#include <msp430.h>
#include "driverlib.h"
#include "stdint.h"
#include <stddef.h>
#include <string.h>


#define RX_BUFFER_LENGTH 100

static volatile uint8_t RXbuffer[RX_BUFFER_LENGTH];
static volatile uint8_t RXbufferIDX;

#define RX_BUFFER_LENGTH1 100

static volatile uint8_t RXbuffer1[RX_BUFFER_LENGTH1];
static volatile uint8_t RXbufferIDX1;


// -------------------------------------------------------------------------
// UART SEND/PARSE STRING FUNCTIONS
// -------------------------------------------------------------------------

// ------------------------------------------------------------------------------
// UART interface
// -------------------------------------------------------------------------------

//USCI_A0
#define UART_TX_READY       (UCA0IFG & UCTXIFG)
#define UART_RX_READY       (UCA0IFG & UCRXIFG)
#define UART_TX_DONE        (UCA0IFG & UCTXCPTIFG)
#define UART_RESET_TX_DONE  (UCA0IFG &= ~UCTXCPTIFG)

//USCI_A1
#define UART_TX_READY_1       (UCA1IFG & UCTXIFG)
#define UART_RX_READY_1       (UCA1IFG & UCRXIFG)
#define UART_TX_DONE_1        (UCA1IFG & UCTXCPTIFG)
#define UART_RESET_TX_DONE_1  (UCA1IFG &= ~UCTXCPTIFG)


//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
// ---------------------------------------------------------------
// FUNCTIONS for USCI_A0
// ---------------------------------------------------------------

// Send a single character using UART
static void send_char(char c)
{
    // Sending data through UART test
    while (!UART_TX_READY)
        ;
    UCA0TXBUF = c;
    while (!UART_TX_DONE)
        ;
    UART_RESET_TX_DONE;
}

// Send a string using UART
static void send_str(char str[])
{
    while (*str != '\0')
    {
        send_char(*str);
        str++;
    }
}

static void send_int(int n, int b)
{
    static char digits[] = "0123456789ABCDEF";
    char buffer[5];
    int i = 0, sign;

    if ((sign = n) < 0)
    {
        n = -n;
    }

    do
    {
        buffer[i++] = digits[n % b];
    }
    while ((n /= b) > 0);

    if (sign < 0)
    {
        buffer[i++] = '-';
    }

    while (--i >= 0)
    {
        send_char(buffer[i]);
    }
}

static void new_line()
{
    send_char(0xD);
    send_char(0xA);
}

//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
// ---------------------------------------------------------------
// FUNCTIONS for USCI_A1
// ---------------------------------------------------------------


static void send_char1(char c)
{
    // Sending data through UART test


    while (!UART_TX_READY_1)
        ;
    UCA1TXBUF = c;
    while (!UART_TX_DONE_1)
        ;
    UART_RESET_TX_DONE_1;
}

static void send_str1(char str[])
{
    while (*str != '\0')
    {
        send_char1(*str);
        str++;
    }
}

static void send_int1(int n, int b)
{
    static char digits[] = "0123456789ABCDEF";
    char buffer[5];
    int i = 0, sign;

    if ((sign = n) < 0)
    {
        n = -n;
    }

    do
    {
        buffer[i++] = digits[n % b];
    }
    while ((n /= b) > 0);

    if (sign < 0)
    {
        buffer[i++] = '-';
    }

    while (--i >= 0)
    {
        send_char1(buffer[i]);
    }
}

static void new_line1()
{
    send_char1(0xD);
    send_char1(0xA);
}

//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
// ---------------------------------------------------------------
// UART INITIALIZATIONS
// ---------------------------------------------------------------

void init_UART_A0(void)
{
    // UART1 port
    // 2.0 : TX
    // 2.1 : RX
    P2SEL1 |= (BIT0 | BIT1);
    P2SEL0 &= ~(BIT0 | BIT1);

    // ---------------------------------------------------------------------
    // Initialization of the UART
    // - No parity
    // - LSB first
    // - One stop bit
    // - 8-bit data
    // - UART mode (asynchronous)
    // - SMCLK clock is used (rate = 1MHz)
    // - Erroneous characters rejected
    // - No break characters interrupts
    // - Not dormant
    // - Software reset disabled
    // - Baudrate: 9600 baud
    // ---------------------------------------------------------------------
    UCA0CTLW0 = UCSWRST;    // Reset
    UCA0CTLW0 = UCSSEL__SMCLK;
    // Setting the baudrate
    UCA0BR0 = 6;
    UCA0BR1 = 0x00;
    UCA0MCTLW |= UCOS16 | UCBRF_8;
    UCA0IE |= UCRXIE;                         // Enable USCI_A0 RX interrupt
    UCA0CTLW0 &= ~UCSWRST;  // Unreset
}


void init_UART_A1(void)
{
    // UART1 port
    // 2.5 : TX
    // 2.6 : RX
    P2SEL1 |= (BIT5 | BIT6);
    P2SEL0 &= ~(BIT5 | BIT6);

    UCA1CTLW0 = UCSWRST;    // Reset
    UCA1CTLW0 |= UCSSEL__SMCLK;
    // Setting the baudrate
    UCA1BR0 = 6;
    UCA1BR1 = 0x00;
    UCA1MCTLW |= UCOS16 | UCBRF_8;
    UCA1IE |= UCRXIE;                        // Enable USCI_A1 RX interrupt
    UCA1IE |= UCTXIE;                        // Enable USCI_A1 TX interrupt
    UCA1CTLW0 &= ~UCSWRST;  // Unreset
}


//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
// ---------------------------------------------------------------
// Init the clock
// ---------------------------------------------------------------
static void init_clock(void)
{
    // -------------------------------------------------------------------
    // Setting the clock
    // MCLK at 1MHz sourced by DCO
    // SMCLK at 1MHz sourced by DCO for UART com
    // ACLK at 32Khz sourced by LFXT for I2C com with the sensor bord
    // -------------------------------------------------------------------
    CSCTL0_H = CSKEY >> 8;  // Unlock CS registers
    CSCTL1 = DCOFSEL_0;     // Set DCO to 8 MHz
    CSCTL2 = SELA__LFXTCLK | SELS__DCOCLK | SELM__DCOCLK; // Set ACLK = LFXT (32kHz) and MCLK = SMCLK = DCO.
    CSCTL3 = DIVA__1 | DIVS__1 | DIVM__1;   // All dividers set to 1
    CSCTL0_H = 0x01; // Lock Register
}


//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
//------------------------------------------------------------------------------
// USCI_A0 interrupt vector service routine.
//------------------------------------------------------------------------------

#if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)
#pragma vector=USCI_A0_VECTOR
__interrupt
#elif defined(__GNUC__)
__attribute__((interrupt(USCI_A0_VECTOR)))
#endif
void USCI_A0_ISR(void)
{
    switch (__even_in_range(UCA0IV, USCI_UART_UCTXCPTIFG))
    {
    case USCI_NONE:
        break;
    case USCI_UART_UCRXIFG:

        RXbuffer[RXbufferIDX] = UCA0RXBUF;
        RXbufferIDX = (RXbufferIDX + 1) % RX_BUFFER_LENGTH;
        LPM3_EXIT;
        break;
    case USCI_UART_UCTXIFG:
        break;
    case USCI_UART_UCSTTIFG:
        break;
    case USCI_UART_UCTXCPTIFG:
        break;
    }
}

//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
//------------------------------------------------------------------------------
// USCI_A1 interrupt vector service routine.
//------------------------------------------------------------------------------

#if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)
#pragma vector=USCI_A1_VECTOR
__interrupt
#elif defined(__GNUC__)
__attribute__((interrupt(USCI_A1_VECTOR)))
#endif
void USCI_A1_ISR(void)
{
    //debug string just to know if the interrupt works
    send_str("Success USCI_A1_ISR");
    new_line();

    switch (__even_in_range(UCA1IV, USCI_UART_UCTXCPTIFG))
    {
    case USCI_NONE:
        break;
    case USCI_UART_UCRXIFG:

        RXbuffer1[RXbufferIDX1] = UCA1RXBUF;
        RXbufferIDX1 = (RXbufferIDX1 + 1) % RX_BUFFER_LENGTH1;
        send_str("Data recieved!");
        send_int(RXbufferIDX, 10);
        new_line();
        LPM3_EXIT;
        break;
    case USCI_UART_UCTXIFG:
        break;
    case USCI_UART_UCSTTIFG:
        break;
    case USCI_UART_UCTXCPTIFG:
        break;
    }
}

//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
//MAIN

void main(void)
{
    volatile unsigned j;
    WDTCTL = WDTPW | WDTHOLD;   // Stop Watchdog Timer
    PM5CTL0 &= ~LOCKLPM5;       // This is Needed for MSP430FR5969!

    
    init_clock();
    init_UART_A0();
    init_UART_A1();

    _EINT();			// Enable interrupts globally.

    while (1)
    {
        send_str("begin");
        new_line();

        send_char1('A');
        send_char1('T');
        new_line1();

        send_str("AT sent");
        new_line();

        LPM3;

    }
}

Here we can see that the code never enters in USCI_A1 interrupt.