//
//
// carved from NG's hello.reflect.45.c
//
// l

#include <avr/io.h>
#include <util/delay.h>

#define output(directions,pin) (directions |= pin) // set port direction for output
#define set(port,pin) (port |= pin) // set port pin
#define clear(port,pin) (port &= (~pin)) // clear port pin
//#define pin_test(pins,pin) (pins & pin) // test for port pin
//#define bit_test(byte,bit) (byte & (1 << bit)) // test for bit set
//#define bit_delay_time 100 // bit delay for 9600 with overhead
//#define bit_delay() _delay_us(bit_delay_time) // RS232 bit delay
//#define half_bit_delay() _delay_us(bit_delay_time/2) // RS232 half bit delay
//#define char_delay() _delay_ms(10) // char delay

//#define serial_port PORTB
//#define serial_direction DDRB
//#define serial_pin_out (1 << PB2)

#define led_port PORTB
#define led_direction DDRB
#define led_pin (1 << PB3)

#define nloop 100 // number of loops to accumulate



int main(void) {
   //
   // main
   //
   
   //
   // set clock divider to /1
   //
   CLKPR = (1 << CLKPCE);
   CLKPR = (0 << CLKPS3) | (0 << CLKPS2) | (0 << CLKPS1) | (0 << CLKPS0);
   //
   // initialize output pins
   //
 
   set(led_port, led_pin);
   output(led_direction, led_pin);
  
   while (1) {
     
         //
         // LED off
         //
         set(led_port, led_pin);
         _delay_us(20);
         // LED on
         //
         clear(led_port, led_pin);
         _delay_us(20);
         //
         
              }
   }