static void UARTInterruptHandler(void* isr_context)
{
alt_u32 status = IORD_ALTERA_AVALON_UART_STATUS(UART_BASE);

IOWR_ALTERA_AVALON_UART_STATUS(UART_BASE, 0);

if (status & ALTERA_AVALON_UART_STATUS_RRDY_MSK | )
{
if ( status & ( ALTERA_AVALON_UART_STATUS_PE_MSK) )
{
asm("break");
return;
}
char ch = (char)IORD_ALTERA_AVALON_UART_RXDATA( UART_BASE );
}
}

static void uartInit()
{
alt_u32 control;
int divisor;

control = (ALTERA_AVALON_UART_CONTROL_TRDY_MSK | ALTERA_AVALON_UART_CONTROL_RRDY_MSK | ALTERA_AVALON_UART_CONTROL_E_MSK);
IOWR_ALTERA_AVALON_UART_CONTROL(UART_BASE, control);

divisor = (int) (50000000 / 9600 + 0.5);
IOWR_ALTERA_AVALON_UART_DIVISOR(UART_BASE, divisor);

alt_ic_isr_register(UART_IRQ_INTERRUPT_CONTROLLER_ID, UART_IRQ, UARTInterruptHandler, NULL, 0))
}

int main(void)
{
uartInit();
for (;;)
{
}
}

alt_ic_isr_register(DEV_CONTROLLER_ID, DEV_IRQ_ID, (void*) ISR_UART, 0, 0);
alt_ic_irq_enable(DEV_CONTROLLER_ID, DEV_IRQ_ID);

#include <stdio.h>
#include <string.h>
#include "sys/alt_flash.h"

#include "sys/alt_irq.h"
#include "system.h"

#include "altera_avalon_pio_regs.h"
#include "altera_avalon_timer_regs.h"
//#include "altera_avalon_timer.h"

#include "pwm_avalon_interface_regs.h"
#include "pwm_avalon_interface.h"
#include "pwm_avalon_interface.c"

//********************** Global Variables ***********************************************
volatile unsigned short int led_dir;
volatile int return_code;
volatile unsigned char i = 0;
volatile unsigned int duty_cycle[8] = {499999, 150000, 60000, 10000, 5000, 2500, 800, 1};

//********************** ISR functions **************************************************
static void timer_isr (void * context)
{ volatile unsigned char* led_ptr;
  volatile unsigned char* dir_ptr;

  IOWR_ALTERA_AVALON_TIMER_STATUS(TIMER_BASE, 0);

  dir_ptr = (volatile unsigned char*)context;
  led_ptr = dir_ptr + 1;

  return_code = altera_avalon_pwm_change_duty_cycle(LED_PWM_BASE, duty_cycle[i]);
  IOWR_ALTERA_AVALON_PIO_DATA(LED_PIO_BASE, *led_ptr);

  if(*dir_ptr)
    { *led_ptr >>= 1;
      i--;
    }
  else
    { *led_ptr <<= 1;
      i++;
    }
  if(*led_ptr & 0x81)
    *dir_ptr ^= 0x1;

}

//********************** Auxiliary functions ********************************************
void check_return_code(unsigned int address, int return_code)
{ if(return_code != ALTERA_AVALON_PWM_OK)
;
//          print_error(address, return_code);
}

//********************* Main function ***************************************************
int main (void)
{ void* led_dir_ptr = (void*)&led_dir;

  led_dir = 0x0100;

  //Timer Initialization
  IOWR_ALTERA_AVALON_TIMER_CONTROL(TIMER_BASE, 0x0003);
  IOWR_ALTERA_AVALON_TIMER_STATUS(TIMER_BASE, 0);

  IOWR_ALTERA_AVALON_TIMER_PERIODL(TIMER_BASE, 0x9f00);
  IOWR_ALTERA_AVALON_TIMER_PERIODH(TIMER_BASE, 0x0024);

  //Register ISR for timer event
  alt_ic_isr_register(TIMER_IRQ_INTERRUPT_CONTROLLER_ID, TIMER_IRQ, timer_isr, led_dir_ptr, 0);

  //Initialize PWM and Check Return Code
  return_code = altera_avalon_pwm_init(LED_PWM_BASE, 500000, 1);
  check_return_code(LED_PWM_BASE, return_code);

  //Enable PWM and Check Return Code
  return_code = altera_avalon_pwm_enable(LED_PWM_BASE);
  check_return_code(LED_PWM_BASE, return_code);

  //Start timer and begin the work
  IOWR_ALTERA_AVALON_TIMER_CONTROL(TIMER_BASE, 0x0007);

//  IOWR_ALTERA_AVALON_PIO_DATA(LED_PIO_BASE, led);

  while (1)
   check_return_code(LED_PWM_BASE, return_code);

}