pushbutton interrup for ALTERA cyclonIII development board

pushbutton interrupts don´t work

My Quartus project is a download from http://www.nioswiki.com/exampledesigns/nio...20designexample (http://www.nioswiki.com/exampledesigns/niosii3c120designexample)

20090508a nios2 linux 3c120 125mhz.tar.gz was unpacked (I am not running linux though but uC-OSII with tools on Windows XP)

My ALTERA Cyclone III Development Board be seen at http://www.altera.com/products/devkits/altera/kit-cyc3.html (http://www.altera.com/products/devkits/altera/kit-cyc3.html)

I previously worked on the NEEK board and had the button interrupt working fine there for that board. I ported the code to My new project running on the Cyclone III Development Board and looked up the corresponding definitions in system.h

My code now looks like this :

#define  BSP_BUTTON_ADDR        USER_PB_PIO_4IN_BASE
volatile INT32S      edge_capture;      /* A variable to hold the value of the button pio edge capture register. */
void BSP_HandleButtonInterrupts(void* context, INT32U ID)
{
    volatile int* edge_capture_ptr = (volatile int*) context;
    // Store the value in the Button's edge capture register in *context. 
    *edge_capture_ptr = IORD_ALTERA_AVALON_PIO_EDGE_CAP(BSP_BUTTON_ADDR);
    
    switch(edge_capture) {
           case 0x01:
               registerPushButton(PUSHBUTTON_LEFT);
               break;
           
           case 0x02:
               registerPushButton(PUSHBUTTON_RIGHT); 
               break;
               
           case 0x04:
                registerPushButton(PUSHBUTTON_UP); 
               break;
               
           case 0x08:
                registerPushButton(PUSHBUTTON_DOWN); 
               break;
               
           default:
              break;
    }
    // Reset the Button's edge capture register. 
    IOWR_ALTERA_AVALON_PIO_EDGE_CAP(BSP_BUTTON_ADDR, 0); 
}
void BSP_InitPushButtons(void)
{
    // Recast the edge_capture pointer to match the alt_irq_register() function
    // prototype. 
    void* edge_capture_ptr = (void*) &edge_capture;
    // Enable all 4 button interrupts. 
    IOWR_ALTERA_AVALON_PIO_IRQ_MASK(BSP_BUTTON_ADDR, 0xf);
    // Reset the edge capture register. 
    IOWR_ALTERA_AVALON_PIO_EDGE_CAP(BSP_BUTTON_ADDR, 0x0);
    // Register the interrupt handler. 
    alt_irq_register(USER_PB_PIO_4IN_IRQ, edge_capture_ptr, BSP_HandleButtonInterrupts );
}

When I run the code It seems I get BSP_HandleButtonInterrupts() called continuously making the rest of the code freeze.

When I step into BSP_HandleButtonInterrupts() , *edge_capture_ptr gets the value of 15.

Any suggestions ???

Best regards