Week 13 Assignments

This week assignment is quite similar to the week 10 input devices one, but now we have to choose an output device, mill a board and program it.

Given my final project, I've selected the RGB led as my output device.

I milled the hello.rgb board and soldered all components.

I used a programmer to upload code via ICSP header. Here it is the uploaded code. I just modified it to include some other colors like yellow and purple.

//
//
// hello.RGB.45.c
//
// RGB LED software PWM hello-world
//
// Neil Gershenfeld
// 11/10/10
//
// (c) Massachusetts Institute of Technology 2010
// Permission granted for experimental and personal use;
// license for commercial sale available from MIT.
//

#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 PWM_delay() _delay_us(25) // PWM delay

#define led_port PORTB
#define led_direction DDRB
#define red (1 << PB1)
#define green (1 << PB0)
#define blue (1 << PB2)

int main(void) {
   //
   // main
   //
   unsigned char count, pwm;
   //
   // set clock divider to /1
   //
   CLKPR = (1 << CLKPCE);
   CLKPR = (0 << CLKPS3) | (0 << CLKPS2) | (0 << CLKPS1) | (0 << CLKPS0);
   //
   // initialize LED pins
   //
   set(led_port, red);
   output(led_direction, red);
   set(led_port, green);
   output(led_direction, green);
   set(led_port, blue);
   output(led_direction, blue);
   //
   // main loop
   //
   while (1) {
      //
      // off -> red
      //
      for (count = 0; count < 255; ++count) {
         clear(led_port,red);
         for (pwm = count; pwm < 255; ++pwm)
            PWM_delay();
         set(led_port,red);
         for (pwm = 0; pwm < count; ++pwm)
            PWM_delay();
         }
      //
      // red -> green
      //
      for (count = 0; count < 255; ++count) {
         set(led_port,red);
         clear(led_port,green);
         for (pwm = count; pwm < 255; ++pwm)
            PWM_delay();
         clear(led_port,red);
         set(led_port,green);
         for (pwm = 0; pwm < count; ++pwm)
            PWM_delay();
         }
      // green -> yellow
      //
      for (count = 0; count < 255; ++count) {
         clear(led_port,green);
         clear(led_port,red);
         for (pwm = count; pwm < 255; ++pwm)
            PWM_delay();
         set(led_port,green);
         set(led_port,red);
         for (pwm = 0; pwm < count; ++pwm)
            PWM_delay();
         }

      // yellow -> blue
      //
      for (count = 0; count < 255; ++count) {
         clear(led_port,red);
         clear(led_port,green);
         set(led_port, blue);
         for (pwm = count; pwm < 255; ++pwm)
            PWM_delay();
         clear(led_port,green);
         clear(led_port,red);
         set(led_port,blue);
         for (pwm = 0; pwm < count; ++pwm)
            PWM_delay();
         }
      //
      // blue -> purple 
      //
      for (count = 0; count < 255; ++count) {
         set(led_port,blue);
         clear(led_port,green);
         set(led_port,red);
         for (pwm = count; pwm < 255; ++pwm)
            PWM_delay();
         set(led_port,blue);
         clear(led_port,green);
         set(led_port,red);
         for (pwm = 0; pwm < count; ++pwm)
            PWM_delay();
         }


      //
      // purple -> on
      //
      for (count = 0; count < 255; ++count) {
         clear(led_port,blue);
         set(led_port,green);
         clear(led_port,red);
         for (pwm = count; pwm < 255; ++pwm)
            PWM_delay();
         set(led_port,blue);
         set(led_port,green);
         set(led_port,red);
         for (pwm = 0; pwm < count; ++pwm)
            PWM_delay();
         }

      //
      // on -> off
      //
      for (count = 0; count < 255; ++count) {
         set(led_port,blue);
         set(led_port,green);
         set(led_port,red);
         for (pwm = count; pwm < 255; ++pwm)
            PWM_delay();
         clear(led_port,blue);
         clear(led_port,green);
         clear(led_port,red);
         for (pwm = 0; pwm < count; ++pwm)
            PWM_delay();
         }
      }
   }

In this video you can see the final result doing a full color cycle