title: AVR proteus delay not working
body: <p>I have used an AVR ATMEGA16 block in Proteus and programmed it this way. 
  Some other simple codes work fine. However I do not understand what is wrong with the delay function. The LED is always off. What is wrong?</p>
  
  <p>My Proteus connection is:</p>
  
  <p><a href="http://i.stack.imgur.com/VGNYc.png" rel="nofollow">http://i.stack.imgur.com/VGNYc.png</a></p>
  
  <pre><code>/*****************************************************
  This program was produced by the
  CodeWizardAVR V2.05.3 Standard
  Automatic Program Generator
  © Copyright 1998-2011 Pavel Haiduc, HP InfoTech s.r.l.
  http://www.hpinfotech.com
  
  Project : 
  Version : 
  Date    : 3/8/2015
  Author  : 
  Company : 
  Comments: 
  
  
  Chip type               : ATmega16
  Program type            : Application
  AVR Core Clock frequency: 16.000000 MHz
  Memory model            : Small
  External RAM size       : 0
  Data Stack size         : 256
  *****************************************************/
  
  #include &lt;mega16.h&gt;
  #include &lt;util/delay.h&gt;
  
  // Declare your global variables here
  
  void main(void)
  {
  // Declare your local variables here
  
  // Input/Output Ports initialization
  // Port A initialization
  // Func7=In Func6=In Func5=In Func4=In Func3=In Func2=In Func1=In Func0=In 
  // State7=T State6=T State5=T State4=T State3=T State2=T State1=T State0=T 
  PORTA=0x00;
  DDRA=0x00;
  
  // Port B initialization
  // Func7=In Func6=In Func5=In Func4=In Func3=In Func2=In Func1=In Func0=In 
  // State7=T State6=T State5=T State4=T State3=T State2=T State1=T State0=T 
  PORTB=0x00;
  DDRB=0x00;
  
  // Port C initialization
  // Func7=In Func6=In Func5=In Func4=In Func3=In Func2=In Func1=In Func0=In 
  // State7=T State6=T State5=T State4=T State3=T State2=T State1=T State0=T 
  PORTC=0x00;
  DDRC=0x00;
  
  // Port D initialization
  // Func7=In Func6=In Func5=In Func4=In Func3=In Func2=In Func1=In Func0=Out 
  // State7=T State6=T State5=T State4=T State3=T State2=T State1=T State0=1 
  PORTD=0x01;
  DDRD=0x01;
  
  // Timer/Counter 0 initialization
  // Clock source: System Clock
  // Clock value: Timer 0 Stopped
  // Mode: Normal top=0xFF
  // OC0 output: Disconnected
  TCCR0=0x00;
  TCNT0=0x00;
  OCR0=0x00;
  
  // Timer/Counter 1 initialization
  // Clock source: System Clock
  // Clock value: Timer1 Stopped
  // Mode: Normal top=0xFFFF
  // OC1A output: Discon.
  // OC1B output: Discon.
  // Noise Canceler: Off
  // Input Capture on Falling Edge
  // Timer1 Overflow Interrupt: Off
  // Input Capture Interrupt: Off
  // Compare A Match Interrupt: Off
  // Compare B Match Interrupt: Off
  TCCR1A=0x00;
  TCCR1B=0x00;
  TCNT1H=0x00;
  TCNT1L=0x00;
  ICR1H=0x00;
  ICR1L=0x00;
  OCR1AH=0x00;
  OCR1AL=0x00;
  OCR1BH=0x00;
  OCR1BL=0x00;
  
  // Timer/Counter 2 initialization
  // Clock source: System Clock
  // Clock value: Timer2 Stopped
  // Mode: Normal top=0xFF
  // OC2 output: Disconnected
  ASSR=0x00;
  TCCR2=0x00;
  TCNT2=0x00;
  OCR2=0x00;
  
  // External Interrupt(s) initialization
  // INT0: Off
  // INT1: Off
  // INT2: Off
  MCUCR=0x00;
  MCUCSR=0x00;
  
  // Timer(s)/Counter(s) Interrupt(s) initialization
  TIMSK=0x00;
  
  // USART initialization
  // USART disabled
  UCSRB=0x00;
  
  // Analog Comparator initialization
  // Analog Comparator: Off
  // Analog Comparator Input Capture by Timer/Counter 1: Off
  ACSR=0x80;
  SFIOR=0x00;
  
  // ADC initialization
  // ADC disabled
  ADCSRA=0x00;
  
  // SPI initialization
  // SPI disabled
  SPCR=0x00;
  
  // TWI initialization
  // TWI disabled
  TWCR=0x00;
  
  while (1)
  {
        PORTD.0=1;
        _delay_ms(500);
        PORTD.0=0;
        _delay_ms(500);
  }
  
  
  }// end of program
  </code></pre>