Prop Circuit for Attiny45

/*
Copyright 2011 Dustin L. Westaby

----------------------------------------------------------------------
    Prop Circuit for Attiny45
----------------------------------------------------------------------
Title:      cortana.c
Author:     Dustin Westaby
Date Created:   2/13/11
Last Modified:  9/17/11
Purpose:  Animated output to LEDs

Compiled with AVR-GCC WinAVR

Revisions List:
2/13/11 Initial Draft and test circuit
2/14/11 Updated Comments, re-arranged structure
9/17/11 Timer Off Code Added

----------------------------------------------------------------------
    Fuses:
----------------------------------------------------------------------
 BrownOut Disabled
 CKDIV8
 Int RC Osc 8Mhz + 64ms

----------------------------------------------------------------------
    Inputs:
----------------------------------------------------------------------
 Power up

----------------------------------------------------------------------
    Ouputs:
----------------------------------------------------------------------
 pin    label   connections
----------------------------------------------------------------------
  2     PB3 =   LED
  3     PB4 =   LED
  5     PB0 =   LED
  6     PB1 =   LED
  7     PB2 =   LED

----------------------------------------------------------------------
    Notes:
----------------------------------------------------------------------
 -Program is free to modify, but please keep my name on the author list.

*/

//--------------------------------------
//          Global Variables           |
//--------------------------------------
// 8 MHz Internal Oscillator DIV8 (used for delay subroutines)
// One CPU Cycle = 1us
#define F_CPU 8000000UL/8

// Enumerate up down for use in the fade loops
enum { up, down };

//Option to disable the time out turn off
//0 = OFF, 1 = ON
#define TIMER_ENABLE 1

//--------------------------------------
//              Includes               |
//--------------------------------------
#include <avr/io.h>
#include <util/delay.h>
#include <avr/sleep.h>
#include <inttypes.h>


//--------------------------------------
//          Delay Subroutines          |
//--------------------------------------
//These functions are from the delay.h include, the calls to delay functions
//are re-written here to allow for longer waits.
void delay_ms(uint16_t ms) {
  while ( ms )
  {
    _delay_ms(1);
    ms--;
  }
}

void delay_us(uint16_t us) {
  while ( us )
  {
    _delay_us(1);
    us--;
  }
}

//--------------------------------------
//          Sleep Subroutine           |
//--------------------------------------
void shutdown_and_sleep(void) {

    //setup low power sleep mode
    set_sleep_mode(SLEEP_MODE_PWR_DOWN);

    //send to sleep
    sleep_mode();

    //NOT HIT
    while(1);

}


//--------------------------------------
//               Main                  |
//--------------------------------------
int main (void)
{

  /* ---------------------------------------------------------------- */
  /*                            Initialization                        */
  /* ---------------------------------------------------------------- */
  //Variables used for animations
  int i, count_delay, direction;
  int time_on, time_off, max_value,  min_value, rate_of_change;
  int time_to_off, cycle_count, fade_inc_count;

  //Initialize Port B is an output
  DDRB =  0b00011111;

  /* ---------------------------------------------------------------- */
  /*                Spin Circle Four Times (approx 1s)                */
  /* ---------------------------------------------------------------- */
  i=0;
  count_delay=50;             //Delay between circle movement is 50ms
  for (i = 0; i < 4; i++)
  {
    PORTB = 0b00000001;       //Turn ON only LED 0 for defined delay (50ms)
    delay_ms(count_delay);
    PORTB = 0b00000010;       //Turn ON only LED 1 for defined delay (50ms)
    delay_ms(count_delay);
    PORTB = 0b00000100;       //Turn ON only LED 2 for defined delay (50ms)
    delay_ms(count_delay);
    PORTB = 0b00001000;       //Turn ON only LED 3 for defined delay (50ms)
    delay_ms(count_delay);
    PORTB = 0b00010000;       //Turn ON only LED 4 for defined delay (50ms)
    delay_ms(count_delay);
  }

  /* ---------------------------------------------------------------- */
  /*                     All ON Long (0.8 seconds)                    */
  /* ---------------------------------------------------------------- */
  PORTB = 0b00011111;         //Turn ON all LEDs 01234 for 800ms
  delay_ms(800);

  /* ---------------------------------------------------------------- */
  /*                         Blink Blink                              */
  /* ---------------------------------------------------------------- */
  PORTB = 0b00000000;         //Turn OFF all LEDS 01234 for 100ms
  delay_ms(100);
  PORTB = 0b00011111;         //Turn ON  all LEDs 01234 for 10ms
  delay_ms(10);
  PORTB = 0b00000000;         //Turn OFF all LEDs 01234 for 100ms
  delay_ms(100);
  PORTB = 0b00011111;         //Turn ON  all LEDs 01234 for 100ms
  delay_ms(100);

  /* ---------------------------------------------------------------- */
  /*              Fade In and Out Continuous (Software PWM)           */
  /* ---------------------------------------------------------------- */
  max_value=500;              //Max of 500us for LEDs ON
  min_value=5;                //Max of   5us for LEDs OFF
  time_on=min_value;          //Set Starting Time ON  to 5us
  time_off=max_value;         //Set Starting Time OFF to 500us
  rate_of_change=2;           //This is the speed that the fade goes between min and max
  direction=down;             //Direction is defined for the direction of the fade (in or out)

  time_to_off=5*(54);         //About 5 minutes (54 fades per minute)
  cycle_count=0;              //Use to count the number of times fades to dark
  fade_inc_count=0;           //Used to count iterations of the fade loop

  /* Note: The direction is backwards on purpose, causes the light animation to
           look like it hiccuped for the first fade cycle before reaching a steady fade. */

  while(1)
  {
    //The ratio of ON time and OFF time determines the brightness of the LEDs (DUTY CYLE)
    //By continuously varying the ON time versus the OFF times we get a fade effect.
    PORTB = 0b00011111;       //Turn ON  all LEDs 01234
    delay_us(time_on);
    PORTB = 0b00000000;       //Turn OFF all LEDs 01234
    delay_us(time_off);

    //This is the TimeOut code. Breaks loop.turning off the LEDs.
    if (TIMER_ENABLE)
    {
        fade_inc_count++;
        if (fade_inc_count>(max_value/2))
        {
            fade_inc_count=0;
            cycle_count++;

            if (cycle_count > time_to_off)
            {
                shutdown_and_sleep();
                //does not return
                break;
            }
        }
    }

    if (direction==up)
    {
        //In the UP direction the Time ON increases while the Time OFF decreases.
        //The result is that the LEDs get brighter
      time_on+=rate_of_change;
      time_off-=rate_of_change;

      //When the end of the fade is reached, switch directions
      if (time_on>max_value)
        direction=down;
    }
    else
    {
        //In the DOWN direction the Time ON decreases while the Time OFF increases.
        //The result is that the LEDs get dimmer
      time_on-=rate_of_change;
      time_off+=rate_of_change;

      //When the end of the fade is reached, switch directions
      if (time_on<=min_value)
        direction=up;
    }
  }

  //this code should not be hit, the following is just in case
  set_sleep_mode(SLEEP_MODE_PWR_DOWN);
  sleep_mode();
  while(1);  // Ending infinite loop

}