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+#ifndef main_timer_avr_h
+#define main_timer_avr_h
+/* main_timer.avr.h */
+/* io - Input & Output with Artificial Intelligence (ai) support on AVR. {{{
+ *
+ * Copyright (C) 2008 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 module.
+ * Main timer module is used for the main loop of the io board to ensure it is
+ * executed only to the defined loop time (at the maximum). It uses the
+ * timer/counter 0 of the AVR.
+ */
+
+/**
+ * Initialize the main timer to 4.444 ms.
+ */
+static inline void
+main_timer_init (void)
+{
+ /* Fov = F_io / (prescaler * (TOP + 1))
+ * TOP = 0xff
+ * prescaler = 256
+ * Tov = 1 / Fov = 4.444 ms */
+ TCCR0 = regv (FOC0, WGM00, COM01, COM0, WGM01, CS02, CS01, CS00,
+ 0, 0, 0, 0, 0, 1, 1, 0);
+}
+
+/**
+ * Wait until the main timer overflows.
+ */
+static inline void
+main_timer_wait (void)
+{
+ /* Loop until an overflow of the timer occurs */
+ while (!(TIFR & _BV (TOV0)))
+ ;
+ /* Write 1 to clear */
+ TIFR = _BV (TOV0);
+}
+
+#endif /* main_timer_avr_h */