Add A/D sampler

Sample A/D at the timer tick, placing data in a ring
of samples.

Signed-off-by: Keith Packard <keithp@keithp.com>

6 files changed, 110 insertions, 4 deletions

diff --git a/Makefile b/Makefile
index b6da6b8f..543f8e37 100644
--- a/Makefile
+++ b/Makefile
@@ -20,6 +20,7 @@ INC = \
 	cc1111.h
 
 SRC = \
+	ao_adc.c \
 	ao_task.c \
 	ao_timer.c \
 	ao_panic.c \
diff --git a/ao.h b/ao.h
index 2d434134..fdf6b027 100644
--- a/ao.h
+++ b/ao.h
@@ -20,11 +20,12 @@
 
 #include <stdint.h>
 #include <stdio.h>
+#include <string.h>
 #include "cc1111.h"
 
 #define DATA_TO_XDATA(a)	((void __xdata *) ((uint8_t) (a) | 0xff00))
 
-#define AO_STACK_START	0x21
+#define AO_STACK_START	0x27
 #define AO_STACK_END	0xfe
 #define AO_STACK_SIZE	(AO_STACK_END - AO_STACK_START + 1)
 
@@ -58,4 +59,26 @@ void ao_timer_init(void);
 uint16_t ao_time_atomic(void);
 void ao_delay(uint16_t ticks);
 
+/* ao_adc.c */
+
+#define ADC_RING	32
+
+struct ao_adc {
+	uint16_t	tick;
+	int16_t		accel;
+	int16_t		pres;
+	int16_t		temp;
+	int16_t		v_batt;
+	int16_t		sense_d;
+	int16_t		sense_m;
+};
+
+extern __xdata struct ao_adc	ao_adc_ring[ADC_RING];
+extern __data uint8_t		ao_adc_head;
+
+void ao_adc_isr(void) interrupt 1;
+void ao_adc_init(void);
+void ao_adc_poll(void);
+void ao_adc_get(__xdata struct ao_adc *packet);
+
 #endif /* _AO_H_ */
diff --git a/ao_adc.c b/ao_adc.c
new file mode 100644
index 00000000..d45e10b1
--- /dev/null
+++ b/ao_adc.c
@@ -0,0 +1,73 @@
+/*
+ * 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; 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 "ao.h"
+
+__xdata struct ao_adc	ao_adc_ring[ADC_RING];
+__data uint8_t		ao_adc_head;
+
+void ao_adc_isr(void) interrupt 1
+{
+	uint8_t sequence;
+	uint8_t	__xdata *a;
+	
+	sequence = (ADCCON2 & ADCCON2_SCH_MASK) >> ADCCON2_SCH_SHIFT;
+	a = (uint8_t __xdata *) (&ao_adc_ring[ao_adc_head].accel + sequence);
+	a[0] = ADCL;
+	a[1] = ADCH;
+	if (sequence < 5) {
+		/* start next channel conversion */
+		ADCCON3 = ADCCON3_EREF_VDD | ADCCON3_EDIV_512 | (sequence + 1);
+	} else {
+		/* record this conversion series */
+		ao_adc_ring[ao_adc_head].tick = ao_time;
+		ao_adc_head++;
+		if (ao_adc_head == ADC_RING)
+			ao_adc_head = 0;
+		ao_wakeup(ao_adc_ring);
+	}
+}
+
+void ao_adc_init(void)
+{
+	ADCCFG = ((1 << 0) |	/* acceleration */
+		  (1 << 1) |	/* pressure */
+		  (1 << 2) |	/* temperature */
+		  (1 << 3) |	/* battery voltage */
+		  (1 << 4) |	/* drogue sense */
+		  (1 << 5));	/* main sense */
+	
+	/* enable interrupts */
+	ADCIF = 0;
+	IEN0 |= IEN0_ADCIE;
+}
+
+void ao_adc_poll(void)
+{
+	ADCCON3 = ADCCON3_EREF_VDD | ADCCON3_EDIV_512 | 0;
+}
+
+void ao_adc_get(__xdata struct ao_adc *packet)
+{
+	uint8_t	i = ao_adc_head;
+	if (i == 0)
+		i = ADC_RING;
+	i--;
+	memcpy(packet, &ao_adc_ring[i], sizeof (struct ao_adc));
+}
+
diff --git a/ao_task.c b/ao_task.c
index 0e976d7c..0af5043c 100644
--- a/ao_task.c
+++ b/ao_task.c
@@ -181,6 +181,5 @@ 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 35a019fa..05245359 100644
--- a/ao_test.c
+++ b/ao_test.c
@@ -43,9 +43,15 @@ blink_0(void)
 void
 blink_1(void)
 {
+	static struct ao_adc adc;
+
 	for (;;) {
-		P1 ^= 2;
-		ao_delay(20);
+		ao_sleep(&ao_adc_ring);
+		ao_adc_get(&adc);
+		if (adc.accel < 15900)
+			P1_1 = 1;
+		else
+			P1_1 = 0;
 	}
 }
 
@@ -68,6 +74,9 @@ main(void)
 	/* Set p1_1 and p1_0 to output */
 	P1DIR = 0x03;
 	
+	ao_adc_init();
+	ao_timer_init();
+
 	ao_add_task(&blink_0_task, blink_0);
 	ao_add_task(&blink_1_task, blink_1);
 	ao_add_task(&wakeup_task, wakeup);
diff --git a/ao_timer.c b/ao_timer.c
index 7a81f32e..cb6255d2 100644
--- a/ao_timer.c
+++ b/ao_timer.c
@@ -22,6 +22,7 @@ volatile __data uint16_t ao_time;
 void ao_timer_isr(void) interrupt 9
 {
 	++ao_time;
+	ao_adc_poll();
 	ao_wakeup(DATA_TO_XDATA(&ao_time));
 }