From: Keith Packard <keithp@keithp.com>
Date: Mon, 13 Apr 2009 05:52:47 +0000 (-0700)
Subject: Add 100Hz timer
X-Git-Tag: sn1-flight1~23
X-Git-Url: https://git.gag.com/?p=fw%2Faltos;a=commitdiff_plain;h=823f4f92de0c1f8dd7a644a8e56ffe9822bee6e2

Add 100Hz timer

Use Timer 1 to generate a 100Hz timer interrupt
---

diff --git a/Makefile b/Makefile
index 2fb24898..b6da6b8f 100644
--- a/Makefile
+++ b/Makefile
@@ -21,6 +21,7 @@ INC = \
 
 SRC = \
 	ao_task.c \
+	ao_timer.c \
 	ao_panic.c \
 	ao_test.c \
 	_bp.c
diff --git a/ao.h b/ao.h
index 4fd368c0..2d434134 100644
--- a/ao.h
+++ b/ao.h
@@ -22,7 +22,9 @@
 #include <stdio.h>
 #include "cc1111.h"
 
-#define AO_STACK_START	0x11
+#define DATA_TO_XDATA(a)	((void __xdata *) ((uint8_t) (a) | 0xff00))
+
+#define AO_STACK_START	0x21
 #define AO_STACK_END	0xfe
 #define AO_STACK_SIZE	(AO_STACK_END - AO_STACK_START + 1)
 
@@ -36,6 +38,10 @@ struct ao_task {
 
 #define AO_ERROR_NO_TASK	1
 
+#define ao_interrupt_disable()	(EA = 0)
+#define ao_interrupt_enable()	(EA = 1)
+
+/* ao_task.c */
 int ao_sleep(__xdata void *wchan);
 int ao_wakeup(__xdata void *wchan);
 void ao_add_task(__xdata struct ao_task * task, void (*start)(void));
@@ -43,4 +49,13 @@ void ao_start_scheduler(void);
 void ao_yield(void) _naked;
 void ao_panic(uint8_t reason);
 
+/* ao_timer.c */
+
+volatile __data uint16_t ao_time;
+
+void ao_timer_isr(void) interrupt 9;
+void ao_timer_init(void);
+uint16_t ao_time_atomic(void);
+void ao_delay(uint16_t ticks);
+
 #endif /* _AO_H_ */
diff --git a/ao_task.c b/ao_task.c
index 0af5043c..0e976d7c 100644
--- a/ao_task.c
+++ b/ao_task.c
@@ -181,5 +181,6 @@ ao_start_scheduler(void)
 {
 	ao_cur_task_id = AO_NO_TASK;
 	ao_cur_task = NULL;
+	ao_timer_init();
 	ao_yield();
 }
diff --git a/ao_test.c b/ao_test.c
index 85d523af..35a019fa 100644
--- a/ao_test.c
+++ b/ao_test.c
@@ -45,7 +45,7 @@ blink_1(void)
 {
 	for (;;) {
 		P1 ^= 2;
-		delay(20);
+		ao_delay(20);
 	}
 }
 
@@ -53,7 +53,7 @@ void
 wakeup(void)
 {
 	for (;;) {
-		delay(10);
+		ao_delay(10);
 		ao_wakeup(&blink_chan);
 	}
 }
@@ -62,6 +62,9 @@ void
 main(void)
 {
 	CLKCON = 0;
+	while (!(SLEEP & SLEEP_XOSC_STB))
+		;
+
 	/* Set p1_1 and p1_0 to output */
 	P1DIR = 0x03;
 	
diff --git a/ao_timer.c b/ao_timer.c
new file mode 100644
index 00000000..7a81f32e
--- /dev/null
+++ b/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_time;
+
+void ao_timer_isr(void) interrupt 9
+{
+	++ao_time;
+	ao_wakeup(DATA_TO_XDATA(&ao_time));
+}
+
+uint16_t ao_time_atomic(void)
+{
+	uint8_t ret1;
+	uint16_t ret2;
+	
+	for (;;) {
+		ret1 = ao_time >> 8;
+		ret2 = ao_time;
+		if (ret1 == ((__xdata uint8_t *)(&ret2))[1])
+			break;
+	}
+	return ret2;
+}
+
+#define T1_CLOCK_DIVISOR	8	/* 24e6/8 = 3e6 */
+#define T1_SAMPLE_TIME		30000	/* 3e6/30000 = 100 */
+
+void
+ao_timer_init(void)
+{
+	/* NOTE:  This uses a timer only present on cc1111 architecture. */
+
+	/* disable timer 1 */
+	T1CTL = 0;
+
+	/* set the sample rate */
+	T1CC0H = T1_SAMPLE_TIME >> 8;
+	T1CC0L = T1_SAMPLE_TIME;
+
+	T1CCTL0 = T1CCTL_MODE_COMPARE;
+	T1CCTL1 = 0;
+	T1CCTL2 = 0;
+
+	/* clear timer value */
+	T1CNTL = 0;
+
+	/* enable overflow interrupt */
+	OVFIM = 1;
+	/* enable timer 1 interrupt */
+	T1IE = 1;
+
+	/* enable timer 1 in module mode, dividing by 8 */
+	T1CTL = T1CTL_MODE_MODULO | T1CTL_DIV_8;
+}
+
+void
+ao_delay(uint16_t ticks)
+{
+	uint16_t until = ao_time_atomic() + ticks;
+
+	while ((int16_t) (until - ao_time_atomic()) > 0)
+		ao_sleep(DATA_TO_XDATA(&ao_time));
+}