TMS320F28379D: Using Macro "Device_Delay_US" causes debugging issues on TMS320F28379D Delfino Launchpad

Part Number: TMS320F28379D
Other Parts Discussed in Thread: C2000WARE

hi Guys,
I took a Driverlib example from the directory \ ti \ c2000 \ C2000Ware_2_00_00_02 \ driverlib \ f2837xd \ examples \ epwm_ex4_digital_compare.c and extended it by a few lines of code to make the onboard LED blink.

   GPIO_setPadConfig(31, GPIO_PIN_TYPE_STD);    // Enable pullup on GPIO10
    GPIO_writePin(31, 0);                           // Load output latch
    GPIO_setPinConfig(GPIO_31_GPIO31);              // GPIO10 = GPIO10
    GPIO_setDirectionMode(31, GPIO_DIR_MODE_OUT);   // GPIO10 = output

    //
    // Loop indefinitely
    //
    do {
        GPIO_writePin(31,1);
        DEVICE_DELAY_US(80000);                  // ON delay
        GPIO_writePin(31,0);                     // Turn off LED
       DEVICE_DELAY_US(80000);                   // OFF delay
        } while(1);

if I use these lines of code, I can not debug the example - the code does not appear in the debug-window

Is not that possible or am I doing something wrong?
many thanks

CCS 9.1.0.00010

C2000Ware2_00_00_02