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-rw-r--r--digital/mimot/src/asserv/timer.avr.c68
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diff --git a/digital/mimot/src/asserv/timer.avr.c b/digital/mimot/src/asserv/timer.avr.c
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+/* timer.avr.c */
+/* asserv - Position & speed motor control on AVR. {{{
+ *
+ * Copyright (C) 2005 Nicolas Schodet
+ *
+ * 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.
+ *
+ * }}} */
+#include "common.h"
+
+#include "modules/utils/utils.h"
+#include "modules/motor/encoder/encoder.h"
+#include "io.h"
+
+/** Top timer value. */
+#define TIMER_TOP 255
+/** Number of steps during wait. */
+#define TIMER_STEPS 4
+/** Size of step. */
+#define TIMER_STEP ((TIMER_TOP + 1) / TIMER_STEPS)
+
+/** Initialise the timer. */
+void
+timer_init (void)
+{
+ TCCR0 = regv (FOC0, WGM00, COM01, COM00, WGM01, CS02, CS01, CS00,
+ 0, 0, 0, 0, 0, 1, 0, 0);
+ /* Fov = F_io / (prescaler * (TOP + 1))
+ * TOP = 0xff
+ * prescaler = 256
+ * Tov = 1 / Fov = 4.444 ms */
+}
+
+/** Wait for timer overflow. */
+void
+timer_wait (void)
+{
+ uint8_t i;
+ /* Make small steps with counter updates. */
+ for (i = 1; i < TIMER_STEPS; i++)
+ {
+ while (TCNT0 < i * TIMER_STEP)
+ ;
+ encoder_update_step ();
+ }
+ /* Wait overflow. */
+ while (!(TIFR & _BV (TOV0)))
+ ;
+ /* Write 1 to clear. */
+ TIFR = _BV (TOV0);
+}
+