From c04b8fe1c42dd36b384bdc3379734d6c8bfe7996 Mon Sep 17 00:00:00 2001 From: Jérémy Dufour Date: Sat, 14 Mar 2009 23:24:05 +0100 Subject: * digital/io/src: - clean main timer module. --- digital/io/src/main_timer.h | 69 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 69 insertions(+) create mode 100644 digital/io/src/main_timer.h (limited to 'digital/io/src/main_timer.h') diff --git a/digital/io/src/main_timer.h b/digital/io/src/main_timer.h new file mode 100644 index 00000000..1b69a743 --- /dev/null +++ b/digital/io/src/main_timer.h @@ -0,0 +1,69 @@ +#ifndef main_timer_h +#define main_timer_h +/* main_timer.h */ +/* io - Input & Output with Artificial Intelligence (ai) support on AVR. {{{ + * + * Copyright (C) 2009 Dufour Jérémy + * + * APBTeam: + * Web: http://apbteam.org/ + * Email: team AT apbteam DOT org + * + * 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * + * }}} */ + +/** + * @file Main timer. + * The main timer is responsible for making the main loop executed regularly + * to a specific time (at least). + * + * Sometimes, the main loop can be executed less frequently that we want + * because it takes too much time! This is bad and should be avoided. + * + * The main timer used the timer/counter 0 of the AVR. + */ + +/** + * Configuration of prescaler of timer/counter 0. + */ +#define MT_TC0_PRESCALER 256 +/** + * Configuration of the top of timer/counter 0. + */ +#define MT_TC0_TOP 255 +/** + * Configuration of the period timer/counter 0 (in millisecond). + */ +#define MT_TC0_PERIOD ((1 / AC_FREQ / MT_TC0_PRESCALER * (MT_TC0_TOP + 1)) \ + * 1000) + +/** + * Initialize the main timer to 4.444 ms. + */ +void +main_timer_init (void); + +/** + * Wait until the main timer overflows. + * @return + * - 0 if we are on time (we have not reached overflow before calling this + * function). + * - 1 if we have already reached overflow. + */ +uint8_t +main_timer_wait (void); + +#endif /* main_timer_h */ -- cgit v1.2.3