funkfinger

// based largely on Atmel's AVR136: Low-Jitter Multi-Channel Software PWM Application Note:
// http://www.atmel.com/dyn/resources/prod_documents/doc8020.pdf

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

#define CHMAX 3 // maximum number of PWM channels
#define PWMDEFAULT 0x00 // default PWM value at start up for all channels

neilalbrock

## Solve Every Sudoku Puzzle

## See http://norvig.com/sudoku.html

## Throughout this program we have:
##   r is a row,    e.g. 'A'
##   c is a column, e.g. '3'
##   s is a square, e.g. 'A3'
##   d is a digit,  e.g. '9'
##   u is a unit,   e.g. ['A1','B1','C1','D1','E1','F1','G1','H1','I1']