// AT90USB/SUDD.c 
// Simple Usb Data-acquisition Device 
// S. Salewski 10-SEP-2007
// Start minicom with 8N1 configuration to see debug messages
// The real work happens inside of interrupt-service-routines

#include <avr/io.h>
#include <avr/interrupt.h>
#include "usart_drv.h"
#include "usb_drv.h"

static void blinkforever(void);

int
main(void)
{
  cli();
  CLKPR = (1<<7);
  CLKPR = 0; // clock prescaler == 0, so we have 16 MHz mpu frequency with our 16 MHz crystal
  USART_Init();
  USART_WriteString("\r\n----------------------------------------------------------\r\n");
  UsbDevLaunchDevice(false);
  // UsbDevWaitStartupFinished(); // no reason to wait
  blinkforever();
  return 0;
}

// a LED connected to PORTA0 will toggle to indicate the unused processing power
static void
blinkforever(void)
{
  int i = 0; // to suppress warning of avr-gcc
  DDRA |= (1<<DDA0);
  while (1)
  {
    while (i++)
    {
      asm volatile ("nop"); // necessary for avr-gcc 4.x to prevent removing of empty delay loop
    }
    PORTA ^= (1<<PORTA0);
  }
}