TMS320F280049C: Usage of SCI-A interrupt

#include "F28x_Project.h"
#include "inc/hw_types.h"
#include "driverlib.h"
#include "device.h"
#include "IQmathLib.h"
#include "math.h"
#include "FullBridgeInv.h"
#include "dlog_4ch.h"
#include "F28004x_Gpio.h"
#include "asysctl.h "


void interrupt void uartRxISR();
void interrupt void uartTxISR();
void initSCIA();

// UART receive interrupt handler
interrupt void uartRxISR(void)
{
    // Read received data
    char receivedChar = SciaRegs.SCIRXBUF.all;
    
    // Echo received character back
    SciaRegs.SCITXBUF.all = receivedChar;
    
    // Clear interrupt flag
    SciaRegs.SCIFFRX.bit.RXFFINTCLR = 1;
    PieCtrlRegs.PIEACK.all |= PIEACK_GROUP9;
}

// UART transmit interrupt handler
interrupt void uartTxISR(void)
{
    // Clear interrupt flag
    SciaRegs.SCIFFTX.bit.TXFFINTCLR = 1;
    PieCtrlRegs.PIEACK.all |= PIEACK_GROUP9;
}

int main(void)
{
    // Initialize system
    InitSysCtrl();
    
    // Initialize GPIO for SCI
    InitSciaGpio();
    
    // Initialize PIE
    InitPieCtrl();
    IER = 0x0000;
    IFR = 0x0000;
    
    PieVectTable.SCIA_RX_INT = &uartRxISR;
    PieCtrlRegs.PIEIER9.bit.INTx1 = 1;
    EnableInterrupts();
    initSCIA(); 
    
    while(1)
    {
        // Main application loop
    }
}
void initSCIA(void)
{
    SciaRegs.SCIFFTX.all = 0xE040;
    SciaRegs.SCIFFRX.all = 0x2044;
    SciaRegs.SCIFFCT.all = 0x0;

    // Note: Clocks were turned on to the SCIA peripheral
    // in the InitSysCtrl() function
    //
    SciaRegs.SCICCR.all = 0x0007;           // 1 stop bit,  No loopback
                                            // No parity, 8 char bits,
                                            // async mode, idle-line protocol
    SciaRegs.SCICTL1.all = 0x0003;          // enable TX, RX, internal SCICLK,
                                            // Disable RX ERR, SLEEP, TXWAKE
    SciaRegs.SCICTL2.all = 0x0003;
    SciaRegs.SCICTL2.bit.TXINTENA = 1;
    SciaRegs.SCICTL2.bit.RXBKINTENA = 1;

    //
    // SCIA at 9600 baud
    // @LSPCLK = 25 MHz (100 MHz SYSCLK) HBAUD = 0x01  and LBAUD = 0x44.
    //
    SciaRegs.SCIHBAUD.all = 0x0001;
    SciaRegs.SCILBAUD.all = 0x0044;

    SciaRegs.SCICTL1.all = 0x0023;          // Relinquish SCI from Reset
}