wavy.c

/*

 Wavy Clock
 Copyright 2014 Nicholas W. Sayer
 
 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation; either version 2 of the License, or
 (at your option) any later version.
 
 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.
 
 You should have received a copy of the GNU General Public License along
 with this program; if not, write to the Free Software Foundation, Inc.,
 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

/*
 * This code will keep a long-term average pulse rate of 1 Hz,
 * but will do so by tick at a speed proportional to a sine wave.
 *
 */

#if defined(UNIT_TEST)
// On *nix, there is no PROGMEM. Just make it go away and turn the
// pgm_read operations into just pointer derefs.
#define PROGMEM
#define pgm_read_byte(x) *(x)
#else
#include <avr/pgmspace.h>
#endif

#include "base.h"

// The magic is that the sum of all of the elements of this table = 9 * the size of the table.
PROGMEM const unsigned char sin_table[] = {9, 12, 15, 17, 18, 18, 17, 16, 13, 10, 8, 5, 2, 1, 0, 0, 1, 3, 6};

void loop() {
  while(1) {
    for(unsigned char i = 0; i < sizeof(sin_table) / sizeof(unsigned char); i++) {
      doTick();
      for(unsigned char j = 0; j < pgm_read_byte(sin_table + i); j++)
        doSleep();
    }
  }
}