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-rw-r--r--digital/io/src/pwm.c101
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diff --git a/digital/io/src/pwm.c b/digital/io/src/pwm.c
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+/* pwm.c */
+/* io - Input & Output with Artificial Intelligence (ai) support on AVR. {{{
+ *
+ * Copyright (C) 2009 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 "pwm.h"
+
+#include "modules/utils/utils.h"
+#include "io.h"
+
+/** Delay for LMD18200. */
+#ifndef HOST
+# define PWM_LMD18200_DELAY_US 1
+#else
+# define PWM_LMD18200_DELAY_US 0
+#endif
+
+#ifdef HOST
+extern uint16_t OCR1A;
+extern uint8_t PORTB;
+#endif
+
+/** Stop timer. PWM is set to zero when it reaches zero. */
+uint16_t pwm_stop_timer;
+
+/** Initialise PWM. */
+void
+pwm_init (void)
+{
+#ifndef HOST
+ /* Fast PWM, TOP = 0x3ff, OCnA, OCnB & OCnC with positive logic.
+ f_IO without prescaler.
+ Fpwm = f_IO / (prescaler * (1 + TOP)) = 14400 Hz. */
+ TCCR1A =
+ regv (COM1A1, COM1A0, COM1B1, COM1B0, COM1C1, COM1C0, WGM11, WGM10,
+ 1, 0, 1, 0, 1, 0, 1, 1);
+ TCCR1B = regv (ICNC1, ICES1, 5, WGM13, WGM12, CS12, CS11, CS10,
+ 0, 0, 0, 0, 1, 0, 0, 1);
+ /* Enable pwm and direction outputs in DDRB. */
+ IO_DDR (PWM_IO) |= IO_BV (PWM_IO);
+ IO_DDR (PWM_DIR_IO) |= IO_BV (PWM_DIR_IO);
+#endif
+}
+
+/**
+ * Set a PWM for a given time.
+ * - value: PWM value (-PWM_MAX..+PWM_MAX).
+ * - timer: timer after which the PWM is stopped, or 0 for infinite.
+ */
+void
+pwm_set (int16_t value, uint16_t timer)
+{
+ if (value == 0)
+ {
+ PWM_OCR = 0;
+ }
+ else if (value > 0)
+ {
+ IO_PORT (PWM_DIR_IO) |= IO_BV (PWM_DIR_IO);
+ if (PWM_LMD18200_DELAY_US)
+ utils_delay_us (PWM_LMD18200_DELAY_US);
+ PWM_OCR = value;
+ }
+ else
+ {
+ IO_PORT (PWM_DIR_IO) &= ~IO_BV (PWM_DIR_IO);
+ if (PWM_LMD18200_DELAY_US)
+ utils_delay_us (PWM_LMD18200_DELAY_US);
+ PWM_OCR = -value;
+ }
+ pwm_stop_timer = timer;
+}
+
+/** Update PWM, should be called at regular interval. */
+void
+pwm_update (void)
+{
+ if (pwm_stop_timer && --pwm_stop_timer == 0)
+ pwm_set (0, 0);
+}
+