Interrupt code problem

[Altera_Forum]

Hi, 

 Actually I am a beginner in using niosII. Currently I am having some trouble in trying the interrupt code.  This is a simple interrupt code. I am using SW0 and SW1 as the buttons.  But its not working.  The output showing in nios2 console is just "none" no changes happening when I slide the switch.    # include "alt_types.h"# include "altera_avalon_pio_regs.h"# include "sys/alt_irq.h"# include "system.h"# include <stdio.h># include <unistd.h>   /* A variable to hold the value of the button pio edge capture register. */ volatile int edge_capture; int count = 0;   int handle_interrupt();  # ifdef PIO_1_BASE static void handle_button_interrupts(void* context, alt_u32 id) {    volatile int* edge_capture_ptr = (volatile int*) context;  *edge_capture_ptr = IORD_ALTERA_AVALON_PIO_EDGE_CAP(PIO_1_BASE);  count += handle_interrupt(*edge_capture_ptr);  printf ("Total count = %d\n", count);  IOWR_ALTERA_AVALON_PIO_EDGE_CAP(PIO_1_BASE, 0); } /* Initialize the button_pio. */ static void init_button_pio() {      volatile void* edge_capture_ptr = (void *) &edge_capture;  IOWR_ALTERA_AVALON_PIO_IRQ_MASK(PIO_1_BASE, 0xf);  IOWR_ALTERA_AVALON_PIO_EDGE_CAP(PIO_1_BASE, 0x0);  alt_irq_register( PIO_1_IRQ, edge_capture_ptr,  handle_button_interrupts ); }    # endif   static void initial_message() {  printf("\n\n**************************\n");  printf("* Hello from Nios II! *\n");  printf("**************************\n"); }   int main(void) {    /* Initialize the button pio. */  # ifdef PIO_1_BASE  init_button_pio();# endif    alt_irq_enable_all(PIO_1_IRQ); /* Initial message to output. */    initial_message();   /* Continue counting loop. */    while( 1 )  {  usleep(100000);  if(edge_capture!=0)  {  handle_interrupt(edge_capture);  }  else  {  printf("none \n");  }  }  return 0; }   int handle_interrupt(int button) {  switch (button)  {  case 0x1:  printf("Button 1");  return 1;  break;  case 0x2:  printf( "Button 2 \n");  return 2;  break;  case 0x3:  printf( "Both 3\n");  return 3;  break;  default:  printf( "Button press 0x%x UNKNOWN!!\n", button);  return 0;  break;  } }       Can anyone help me out??  Thanks in advance.

[Altera_Forum]

Hi, maybe in you interrupt function, you should write  

IOWR_ALTERA_AVALON_PIO_EDGE_CAP(PIO_1_BASE, 1);  Avoid printf() in interrupts  Here, you could post your code within [ code] balises  (Instead of printf(), you could light up some LEDs)

[Altera_Forum]

Look at the sample code there: http://www.alteraforum.com/forum/showthread.php?t=41438&p=171308#post171308 (http://www.alteraforum.com/forum/showthread.php?t=41438&p=171308#post171308)