MSP-EXP430FR5994: Uart loopback example receive with DMA

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//******************************************************************************
//!  EUSCI_A1 External Loopback test using EUSCI_A_UART_init API
//!
//!  Description: This demo connects TX to RX of the MSP430 UART
//!  The example code shows proper initialization of registers
//!  and interrupts to receive and transmit data.
//!
//!  ACLK = BRCLK = 32.768kHz, MCLK = SMCLK = DCO = ~1MHz
//!
//!
//!      Tested on MSP430FR5969
//!             -----------------
//!       RST -|     P2.0/UCA1TXD|----|
//!            |                 |    |
//!            |                 |    |
//!            |     P2.1/UCA1RXD|----|
//!            |                 |
//!
//! This example uses the following peripherals and I/O signals.  You must
//! review these and change as needed for your own board:
//! - UART peripheral
//! - GPIO Port peripheral (for UART pins)
//! - UCA1TXD
//! - UCA1RXD
//!
//! This example uses the following interrupt handlers.  To use this example
//! in your own application you must add these interrupt handlers to your
//! vector table.
//! - USCI_A1_VECTOR.
//******************************************************************************
#include "LP_bspFuncs_BQUart.h"


#define BQUART_DMA_RX_TRIGGER         DMA1TSEL__UCA1RXIFG
#define TOTALBOARDS       2               //all boards in stack, including base device
#define MAXBYTES 8*(TOTALBOARDS-1)

uint16_t dma_value[MAXBYTES] = {0};

uint16_t i;
uint8_t RXData = 0, TXData = 54;
uint8_t check = 0;

extern void configure_pins_BQUart(void);
void init_clock(void);

void DMA_Init(){
    __data20_write_long((uintptr_t)&DMA1SA, (uintptr_t)&BQUART_RXBUF);
    __data20_write_long((uintptr_t)&DMA1DA, (uintptr_t) dma_value);

    DMA1CTL &= ~DMAEN;
    DMACTL0 |= BQUART_DMA_RX_TRIGGER;
    DMACTL4 |= DMARMWDIS;

    //Single transfer; increment destination address; source address unchanged;
    //byte to byte transfer source to DMA; byte to byte transfer destination to DMA;
    //rising edge DMA trigger; DMA enable

    DMA1CTL |= DMADT_0|DMADSTINCR_3|DMASRCINCR_0|DMASRCBYTE__BYTE|DMADSTBYTE__BYTE|DMA_TRIGGER_RISINGEDGE|DMAEN;

}

void main(void)
{
    uint32_t u32ClockFrequencyCheck = 0u;
    // stop watchdog
    WDT_A_hold(WDT_A_BASE);

    init_clock();

    u32ClockFrequencyCheck = CS_getMCLK();
    u32ClockFrequencyCheck = CS_getSMCLK();

    configure_pins_BQUart();
    DMA_Init();


    BQUART_REG  &= ~BQUART_TX_PIN;
    __delay_cycles(44000);          //Transmit 2.5ms low
    BQUART_REG  = BQUART_TX_PIN;
    __delay_cycles(56000);

    // Configure UART pins
    //Set P2.0 and P2.1 as Secondary Module Function Input.
    /*

    * Select Port 2d
    * Set Pin 0, 1 to input Secondary Module Function, (UCA1TXD/UCA1SIMO, UCA1RXD/UCA1SOMI).
    */
    GPIO_setAsPeripheralModuleFunctionInputPin(
        BQUART_TX_PORT,
        BQUART_TX_PIN + BQUART_RX_PIN,
        BQUART_SELECT_FUNCTION
    );

    /*
     * Disable the GPIO power-on default high-impedance mode to activate
     * previously configured port settings
     */



    BQUART_initParam param = {0};

    param.clockPrescalar = 4,
    param.firstModReg = 0,
    param.secondModReg = 0,
    param.selectClockSource = BQUART_CLOCKSOURCE;
    param.parity =            BQUART_PARITY;
    param.msborLsbFirst =     BQUART_BITORDER;
    param.numberofStopBits =  BQUART_STOPBIT;
    param.uartMode =          BQUART_MODE;
    param.overSampling =      BQUART_OVERSAMPLING;


    if(STATUS_FAIL == BQUART_INIT(BQUART, &param))
    {
           return;
    }


    BQUART_enable(BQUART);


    __enable_interrupt();
    while (1)
    {
        TXData = TXData+1;                      // Increment TX data
        // Load data onto buffer
        DMA1SZ = 1;
        DMA1CTL |= DMAEN;
        DMA1CTL |= DMAIE;
        while (!(BQUART_IFG & UCTXIFG));
        BQUART_TXBUF = TXData;

        while(check != 1);
        check = 0;

    }
}

#pragma vector=DMA_VECTOR
__interrupt void dmaIsrHandler(void)
{
    switch(__even_in_range(DMAIV, DMAIV_DMA1IFG))
    {
    case DMAIV_DMA1IFG:
        DMA1CTL &= ~DMAIE;
        RXData = dma_value[0];
        if(!(RXData == TXData))                   // Check value
              {
                while(1);
              }
         check =1;

        // Exit low power mode on wake-up
        __bic_SR_register_on_exit(LPM4_bits);
        break;
    case DMAIV_DMA0IFG:
        break;

    case DMAIV_DMA2IFG:
        break;

    case DMAIV_DMA3IFG:
            break;

    case DMAIV_DMA4IFG:
        break;

    case DMAIV_DMA5IFG:
        break;

    default: break;
    }
}

void init_clock(void){
    // LFXT Setup
    //Set PJ.4 and PJ.5 as Primary Module Function Input.
    /*

    * Select Port J
    * Set Pin 4, 5 to input Primary Module Function, LFXT.
    */
    GPIO_setAsPeripheralModuleFunctionInputPin(
        GPIO_PORT_PJ,
        GPIO_PIN4 + GPIO_PIN5,
        GPIO_PRIMARY_MODULE_FUNCTION
    );


    // Set PJ.6 and PJ.7 as Primary Module Function Input, HFXT.
    GPIO_setAsPeripheralModuleFunctionInputPin(
           GPIO_PORT_PJ,
           GPIO_PIN6 + GPIO_PIN7,
           GPIO_PRIMARY_MODULE_FUNCTION
           );

    // Check if one FRAM waitstate is needed for 5962, 5994 device as well!
    FRAMCtl_A_configureWaitStateControl(FRAMCTL_A_ACCESS_TIME_CYCLES_1);


    CS_setExternalClockSource(32768, 16000000);

    CS_initClockSignal(CS_SMCLK, CS_HFXTCLK_SELECT, CS_CLOCK_DIVIDER_4);
    CS_initClockSignal(CS_MCLK, CS_HFXTCLK_SELECT, CS_CLOCK_DIVIDER_1);

    //Set ACLK=LFXT
    CS_initClockSignal(CS_ACLK, CS_LFXTCLK_SELECT, CS_CLOCK_DIVIDER_1);

    //Set the appropriate drive values for each oscillator for the launchpad vs. actual schematic.
    CS_turnOnLFXT(CS_LFXT_DRIVE_3);

    CS_turnOnHFXT(CS_HFXT_DRIVE_16MHZ_24MHZ);


}