problem to send an analog continuous signal through GPIO pins

//###########################################################################
// FILE:   external_interrupt_c28.c
// TITLE:  External Interrupt test Program.
//
//! \addtogroup control_example_list
//! <h1> External Interrupts (external_interrupt)</h1>
//!
//! This program sets up PA0_GPIO0 as XINT1 and PA1_GPIO1 as XINT2.  Two other
//! GPIO signals are used to trigger the interrupt (PE6_GPIO30 triggers
//! XINT1 and PE7_GPIO31 triggers XINT2).
//! Connect a jumper across rows A and B at position 2 and 19 of the ABC header
//! to route PE6_GPIO30 and PE7_GPIO31 to the pins at the base.The user must
// then
//! externally connect these pins(PE6_GPIO30 to PA0_GPIO0 and PE7_GPIO31 to
//! PA1_GPIO1) at the base board for the program to work properly.
//!
//! XINT1 input is synched to SYSCLKOUT
//! XINT2 has a long qualification - 6 samples at 510*SYSCLKOUT each.
//!
//! PF2_GPIO34 will go high outside of the interrupts and low within the
//! interrupts. This signal can also be monitored on a scope.
//!
//! Each interrupt is fired in sequence - XINT1 first and then XINT2
//!
//! \b Watch \b Variables \n
//! - Xint1Count    - Number of times XINT1 interrupt fires
//! - Xint2Count    - Number of times XINT2 interrupt fires
//! - LoopCount     - Number of times through the idle loop
//
//###########################################################################
// $TI Release: F28M35x Support Library v160 $
// $Release Date: Tue Nov  6 08:48:09 CST 2012 $
//###########################################################################

#include "DSP28x_Project.h"     // Device Headerfile and Examples Include File
#include <string.h>

// Prototype statements for functions found within this file.
interrupt void xint1_isr(void);
interrupt void xint2_isr(void);

// Global variables for this example
volatile Uint32 Xint1Count;
volatile Uint32 Xint2Count;
Uint32 LoopCount;

#define DELAY (CPU_RATE/1000*6*510)  //Qual period at 6 samples

void main(void)
{
    Uint32 TempX1Count;
    Uint32 TempX2Count;

// Step 1. Initialize System Control:
// Enable Peripheral Clocks
// This example function is found in the F28M35x_SysCtrl.c file.
    InitSysCtrl();
    
// If project is linked into flash, copy critical code sections to RAM.    
#ifdef _FLASH
   memcpy(&RamfuncsRunStart, &RamfuncsLoadStart, (size_t)&RamfuncsLoadSize);
#endif        

// Step 2. Initalize GPIO:
// This example function is found in the F28M35x_Gpio.c file and
// illustrates how to set the GPIO to it's default state.
// InitGpio();  // Skipped for this example

// Step 3. Clear all interrupts and initialize PIE vector table:
// Disable CPU interrupts
    DINT;

// Initialize PIE control registers to their default state.
// The default state is all PIE interrupts disabled and flags
// are cleared.
// This function is found in the F28M35x_PieCtrl.c file.
    InitPieCtrl();

// Disable CPU interrupts and clear all CPU interrupt flags:
    IER = 0x0000;
    IFR = 0x0000;

// Initialize the PIE vector table with pointers to the shell Interrupt
// Service Routines (ISR).
// This will populate the entire table, even if the interrupt
// is not used in this example.  This is useful for debug purposes.
// The shell ISR routines are found in F28M35x_DefaultIsr.c.
// This function is found in F28M35x_PieVect.c.
    InitPieVectTable();

// Interrupts that are used in this example are re-mapped to
// ISR functions found within this file.
    EALLOW; // This is needed to write to EALLOW protected registers
    PieVectTable.XINT1 = &xint1_isr;
    PieVectTable.XINT2 = &xint2_isr;
    EDIS;  // This is needed to disable write to EALLOW protected registers

// Step 4. Initialize all the Device Peripherals:
// This function is found in F28M35x_InitPeripherals.c
// InitPeripherals(); // Not required for this example

// Step 5. User specific code, enable interrupts:

// Clear the counters
    Xint1Count = 0; // Count XINT1 interrupts
    Xint2Count = 0; // Count XINT2 interrupts
    LoopCount = 0; // Count times through idle loop

// Enable XINT1 and XINT2 in the PIE: Group 1 interrupt 4 & 5
// Enable INT1 which is connected to WAKEINT:
    PieCtrlRegs.PIECTRL.bit.ENPIE = 1;         // Enable the PIE block
    PieCtrlRegs.PIEIER1.bit.INTx4 = 1;         // Enable PIE Group 1 INT4
    PieCtrlRegs.PIEIER1.bit.INTx5 = 1;         // Enable PIE Group 1 INT5
    IER |= M_INT1;                             // Enable CPU INT1
    EINT;                                      // Enable Global Interrupts

// PE6_GPIO30 & PE7_GPIO31 are outputs, start PE6_GPIO30 high and PE7_GPIO31 low
    EALLOW;
    GpioG1DataRegs.GPASET.bit.GPIO30 = 1;        // Load the output latch
    GpioG1CtrlRegs.GPAMUX2.bit.GPIO30 = 0;       // GPIO
    GpioG1CtrlRegs.GPADIR.bit.GPIO30 = 1;        // output

    GpioG1DataRegs.GPACLEAR.bit.GPIO31 = 1;      // Load the output latch
    GpioG1CtrlRegs.GPAMUX2.bit.GPIO31 = 0;       // GPIO
    GpioG1CtrlRegs.GPADIR.bit.GPIO31 = 1;        // output
    EDIS;

// PA0_GPIO0 and PA1_GPIO1 are inputs
    EALLOW;
    GpioG1CtrlRegs.GPAMUX1.bit.GPIO0 = 0;        // GPIO
    GpioG1CtrlRegs.GPADIR.bit.GPIO0 = 0;         // input
    GpioG1CtrlRegs.GPAQSEL1.bit.GPIO0 = 0;       // XINT1 Synch to SYSCLKOUT
                                                 // only

    GpioG1CtrlRegs.GPAMUX1.bit.GPIO1 = 0;        // GPIO
    GpioG1CtrlRegs.GPADIR.bit.GPIO1 = 0;         // input
    GpioG1CtrlRegs.GPAQSEL1.bit.GPIO1 = 2;       // XINT2 Qual using 6 samples
    GpioG1CtrlRegs.GPACTRL.bit.QUALPRD0 = 0xFF;  // Each sampling window is
                                                 // 510*SYSCLKOUT
    EDIS;

// PA0_GPIO0 is XINT1, PA1_GPIO1 is XINT2
    EALLOW;
    GpioG1TripRegs.GPTRIP4SEL.bit.GPTRIP4SEL = 0; //Map Trip Input 4(XINT1) to
                                                  // PA0_GPIO0
    GpioG1TripRegs.GPTRIP5SEL.bit.GPTRIP5SEL = 1; //Map Trip Input 5(XINT2) to
                                                  // PA1_GPIO1
    EDIS;

// Configure XINT1 and XINT2
    XIntruptRegs.XINT1CR.bit.POLARITY = 0;     // Falling edge interrupt
    XIntruptRegs.XINT2CR.bit.POLARITY = 1;     // Rising edge interrupt

// Enable XINT1 and XINT2
    XIntruptRegs.XINT1CR.bit.ENABLE = 1;       // Enable XINT1
    XIntruptRegs.XINT2CR.bit.ENABLE = 1;       // Enable XINT2

// PF2_GPIO34 will go low inside each interrupt.  Monitor this on a scope
    EALLOW;
    GpioG1CtrlRegs.GPBMUX1.bit.GPIO34 = 0;       // GPIO
    GpioG1CtrlRegs.GPBDIR.bit.GPIO34 = 1;        // output
    EDIS;

// Step 6. IDLE loop:
    for(;;)
    {

        TempX1Count = Xint1Count;
        TempX2Count = Xint2Count;

        // Trigger both XINT1
        GpioG1DataRegs.GPBSET.bit.GPIO34 = 1; // PF2_GPIO34 is high
        GpioG1DataRegs.GPACLEAR.bit.GPIO30 = 1; // Lower PE6_GPIO30, trigger
                                                // XINT1
        while(Xint1Count == TempX1Count) {}

        // Trigger both XINT2

        GpioG1DataRegs.GPBSET.bit.GPIO34 = 1; // PF2_GPIO34 is high
        DELAY_US(DELAY);                    // Wait for Qual period
        GpioG1DataRegs.GPASET.bit.GPIO31 = 1; // Raise PE7_GPIO31, trigger XINT2
        while(Xint2Count == TempX2Count) {}

        // Check that the counts were incremented properly and get ready
        // to start over.
        if(Xint1Count == TempX1Count+1 && Xint2Count == TempX2Count+1)
        {
            LoopCount++;
            GpioG1DataRegs.GPASET.bit.GPIO30 = 1; // raise PE6_GPIO30
            GpioG1DataRegs.GPACLEAR.bit.GPIO31 = 1; // lower PE7_GPIO31
        }
        else
        {
            asm ("      ESTOP0"); // stop here
        }

    }

}

// Step 7. Insert all local Interrupt Service Routines (ISRs) and functions
// here:
// If local ISRs are used, reassign vector addresses in vector table as
// shown in Step 5

interrupt void xint1_isr(void)
{
    GpioG1DataRegs.GPBCLEAR.all = 0x4;   // PF2_GPIO34 is low
    Xint1Count++;

    // Acknowledge this interrupt to get more from group 1
    PieCtrlRegs.PIEACK.all = PIEACK_GROUP1;
}

interrupt void xint2_isr(void)
{
    GpioG1DataRegs.GPBCLEAR.all = 0x4;   // PF2_GPIO34 is low
    Xint2Count++;

    // Acknowledge this interrupt to get more from group 1
    PieCtrlRegs.PIEACK.all = PIEACK_GROUP1;
}