1 files changed, 80 insertions, 0 deletions
diff --git a/src/avr/ao_timer.c b/src/avr/ao_timer.c
new file mode 100644
index 00000000..d2ea2be7
--- /dev/null
+++ b/src/avr/ao_timer.c
@@ -0,0 +1,80 @@
+/*
+ * Copyright © 2009 Keith Packard <keithp@keithp.com>
+ *
+ * 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; version 2 of the License.
+ *
+ * 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 "ao.h"
+
+volatile __data uint16_t ao_tick_count;
+
+uint16_t ao_time(void)
+{
+	uint16_t	v;
+	ao_arch_critical(
+		v = ao_tick_count;
+		);
+	return v;
+}
+
+#define T1_CLOCK_DIVISOR	8	/* 24e6/8 = 3e6 */
+#define T1_SAMPLE_TIME		30000	/* 3e6/30000 = 100 */
+
+#if HAS_ADC
+volatile __data uint8_t	ao_adc_interval = 1;
+volatile __data uint8_t	ao_adc_count;
+#endif
+
+void
+ao_debug_out(char c);
+
+ISR(TIMER1_COMPA_vect)
+{
+	++ao_tick_count;
+#if HAS_ADC
+	if (++ao_adc_count == ao_adc_interval) {
+		ao_adc_count = 0;
+		ao_adc_poll();
+	}
+#endif
+}
+
+#if HAS_ADC
+void
+ao_timer_set_adc_interval(uint8_t interval) __critical
+{
+	ao_adc_interval = interval;
+	ao_adc_count = 0;
+}
+#endif
+
+void
+ao_timer_init(void)
+{
+	TCCR1A = ((0 << WGM11) |	/* CTC mode, OCR1A */
+		  (0 << WGM10));	/* CTC mode, OCR1A */
+	TCCR1B = ((0 << ICNC1) |	/* no input capture noise canceler */
+		  (0 << ICES1) |	/* input capture on falling edge (don't care) */
+		  (0 << WGM13) |	/* CTC mode, OCR1A */
+		  (1 << WGM12) |	/* CTC mode, OCR1A */
+		  (3 << CS10));		/* clk/64 from prescaler */
+
+#if TEENSY
+	OCR1A = 2500;			/* 16MHz clock */
+#else
+	OCR1A = 1250;			/* 8MHz clock */
+#endif
+
+	TIMSK1 = (1 << OCIE1A);		/* Interrupt on compare match */
+}