X-Git-Url: https://git.gag.com/?p=fw%2Faltos;a=blobdiff_plain;f=src%2Fattiny%2Fao_clock.c;fp=src%2Fattiny%2Fao_clock.c;h=a381b47f71ea233e20f651cb865dc9cea0bb5f44;hp=0000000000000000000000000000000000000000;hb=64500ab11ab76d2309608f8e02a1dd9658963b3e;hpb=16bad3b6ab65cf31b19152127cb6af69142c5c12

diff --git a/src/attiny/ao_clock.c b/src/attiny/ao_clock.c
new file mode 100644
index 00000000..a381b47f
--- /dev/null
+++ b/src/attiny/ao_clock.c
@@ -0,0 +1,114 @@
+/*
+ * Copyright © 2012 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 AO_TICK_TYPE	ao_tick_count;
+static volatile AO_TICK_TYPE	ao_wakeup_count;
+
+ISR(TIMER1_COMPA_vect)
+{
+	PORTB ^= 2;
+	++ao_tick_count;
+	if ((int16_t) (ao_tick_count - ao_wakeup_count) >= 0)
+		ao_wakeup((void *) &ao_tick_count);
+}
+
+uint16_t
+ao_time(void)
+{
+	uint16_t	r;
+
+	cli();
+	r = ao_tick_count;
+	sei();
+	return r;
+}
+
+void
+ao_timer_init(void)
+{
+	cli();
+	CLKPR = (1 << CLKPCE);
+	CLKPR = 0;
+	sei();
+
+	/* Overall division ratio is 512 * 125,
+	 * so our 8MHz base clock ends up as a 125Hz
+	 * clock
+	 */
+	TCCR1 = ((1 << CTC1) |		/* Clear timer on match */
+		 (0 << PWM1A) |		/* Not PWM mode */
+		 (0 << COM1A0) |	/* Don't change output pins */
+		 (0 << COM1A1) |	/*  ... */
+		 (1 << CS13) |		/* Prescale by 512 */
+		 (0 << CS12) |		/*  ... */
+		 (1 << CS11) |		/*  ... */
+		 (0 << CS10));		/*  ... */
+	GTCCR = ((0 << PWM1B) |		/* Not PWM mode */
+		 (0 << COM1B1) |	/* Don't change output pins */
+		 (0 << COM1B0) |	/*  ... */
+		 (0 << FOC1B) |		/* Don't force output compare */
+		 (0 << FOC1A) |		/*  ... */
+		 (0 << PSR1));		/* Don't bother to reset scaler */
+
+	OCR1A = 0;
+	OCR1B = 0;
+	OCR1C = 124;			/* Divide by as many 5s as we can (5^3 = 125) */
+
+	TIMSK = ((1 << OCIE1A) |	/* Enable TIMER1_COMPA interrupt */
+		 (0 << OCIE1B) |	/* Disable TIMER1_COMPB interrupt */
+		 (0 << TOIE1));		/* Disable TIMER1_OVF interrupt */
+	DDRB |= 2;
+}
+
+#define PER_LOOP	8
+#define US_LOOPS	((AVR_CLOCK / 1000000) / PER_LOOP)
+
+void ao_delay_us(uint16_t us)
+{
+#if US_LOOPS > 1
+	us *= US_LOOPS;
+#endif
+	for (;;) {
+		ao_arch_nop();
+		ao_arch_nop();
+		ao_arch_nop();
+		--us;
+		/* A bit funky to keep the optimizer
+		 * from short-circuiting the test */
+		if (!((uint8_t) (us | (us >> 8))))
+			break;
+	}
+}
+
+void
+ao_delay_until(uint16_t target)
+{
+	cli();
+	ao_wakeup_count = target;
+	while ((int16_t) (target - ao_tick_count) > 0)
+		ao_sleep((void *) &ao_tick_count);
+	sei();
+}
+
+void
+ao_delay(uint16_t ticks)
+{
+	ao_delay_until(ao_time() + ticks);
+}
+