timer.h

   1 /*
   2 Copyright 2011 Jun Wako <wakojun@gmail.com>
   3
   4 This program is free software: you can redistribute it and/or modify
   5 it under the terms of the GNU General Public License as published by
   6 the Free Software Foundation, either version 2 of the License, or
   7 (at your option) any later version.
   8
   9 This program is distributed in the hope that it will be useful,
  10 but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 GNU General Public License for more details.
  13
  14 You should have received a copy of the GNU General Public License
  15 along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16 */
  17
  18 #ifndef TIMER_H
  19 #define TIMER_H 1
  20
  21 #include <stdint.h>
  22
  23 #define TIMER_DIFF(a, b) ((a) >= (b) ?  (a) - (b) : UINT16_MAX - (b) + (a))
  24
  25
  26 extern volatile uint16_t timer_count;
  27
  28
  29 void timer_init(void);
  30 void timer_clear(void);
  31 uint16_t timer_read(void);
  32 uint16_t timer_elapsed(uint16_t last);
  33
  34 #endif