src-avr: Add ADC routines to telescience

Note that SLEEP mode must be disabled or extra ADC interrupts occur,
which messes up saving ADC values to the right channel.

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

6 files changed, 161 insertions, 1 deletions

diff --git a/src-avr/ao.h b/src-avr/ao.h
index 90298a3e..0d278525 100644
--- a/src-avr/ao.h
+++ b/src-avr/ao.h
@@ -65,6 +65,10 @@ extern __xdata struct ao_task *__data ao_cur_task;
 #define AO_NUM_TASKS		16	/* maximum number of tasks */
 #define AO_NO_TASK		0	/* no task id */
 
+#ifdef AVR
+extern uint8_t	ao_cpu_sleep_disable;
+#endif
+
 /*
  ao_task.c
  */
@@ -165,14 +169,22 @@ ao_clock_init(void);
 /*
  * One set of samples read from the A/D converter or telemetry
  */
+#ifdef AVR
+#define NUM_ADC		12
+#endif
+
 struct ao_adc {
 	uint16_t	tick;		/* tick when the sample was read */
+#ifdef AVR
+	uint16_t	adc[NUM_ADC];	/* samples */
+#else
 	int16_t		accel;		/* accelerometer */
 	int16_t		pres;		/* pressure sensor */
 	int16_t		temp;		/* temperature sensor */
 	int16_t		v_batt;		/* battery voltage */
 	int16_t		sense_d;	/* drogue continuity sense */
 	int16_t		sense_m;	/* main continuity sense */
+#endif
 };
 
 #if HAS_ADC
@@ -190,6 +202,7 @@ struct ao_adc {
  */
 
 #define AO_ADC_RING	32
+
 #define ao_adc_ring_next(n)	(((n) + 1) & (AO_ADC_RING - 1))
 #define ao_adc_ring_prev(n)	(((n) - 1) & (AO_ADC_RING - 1))
 
diff --git a/src-avr/ao_adc_avr.c b/src-avr/ao_adc_avr.c
new file mode 100644
index 00000000..e384a28d
--- /dev/null
+++ b/src-avr/ao_adc_avr.c
@@ -0,0 +1,141 @@
+/*
+ * Copyright © 2011 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 __xdata struct ao_adc	ao_adc_ring[AO_ADC_RING];
+volatile __data uint8_t		ao_adc_head;
+
+#define ADC0
+const uint8_t	adc_channels[NUM_ADC] = {
+	0x00,
+	0x01,
+	0x04,
+	0x05,
+	0x06,
+	0x07,
+	0x20,
+	0x21,
+	0x22,
+	0x23,
+	0x24,
+	0x25,
+};
+
+static uint8_t	ao_adc_channel;
+
+
+static uint16_t	ao_adc_int_count;
+static uint16_t	ao_adc_int_error;
+
+#define ADC_CHANNEL_LOW(c)	(((c) & 0x1f) << MUX0)
+#define ADC_CHANNEL_HIGH(c)	((((c) & 0x20) >> 5) << MUX5)
+
+#define ADCSRA_INIT	((1 << ADEN) |		/* Enable ADC */ 		\
+			 (0 << ADATE) |		/* No auto ADC trigger */ 	\
+			 (1 << ADIF) |		/* Clear interrupt */		\
+			 (0 << ADIE) |		/* Enable interrupt */		\
+			 (6 << ADPS0))		/* Prescale clock by 64 */
+
+#define ADCSRB_INIT	((0 << ADHSM) |		/* No high-speed mode */ \
+			 (0 << ACME) |		/* Some comparitor thing */ \
+			 (2 << ADTS0))		/* Free running mode (don't care) */
+
+static void
+ao_adc_start(void)
+{
+	uint8_t	channel = adc_channels[ao_adc_channel];
+	ADMUX = ((0 << REFS1) |				/* AVcc reference */
+		 (1 << REFS0) |				/* AVcc reference */
+		 (1 << ADLAR) |				/* Left-shift results */
+		 (ADC_CHANNEL_LOW(channel)));		/* Select channel */
+
+	ADCSRB = (ADCSRB_INIT |
+		  ADC_CHANNEL_HIGH(channel));		/* High channel bit */
+
+	ADCSRA = (ADCSRA_INIT |
+		  (1 << ADSC) |
+		  (1 << ADIE));				/* Start conversion */
+}
+
+ISR(ADC_vect)
+{
+	uint16_t	value;
+	uint8_t	channel;
+	++ao_adc_int_count;
+	channel = (ADMUX & 0x1f) | (ADCSRB & 0x20);
+	if (adc_channels[ao_adc_channel] != channel)
+		++ao_adc_int_error;
+	value = ADCL;
+	value |= (ADCH << 8);
+	ao_adc_ring[ao_adc_head].adc[ao_adc_channel] = value;
+	if (++ao_adc_channel < NUM_ADC)
+		ao_adc_start();
+	else {
+		ADCSRA = ADCSRA_INIT;
+		ao_adc_ring[ao_adc_head].tick = ao_time();
+		ao_adc_head = ao_adc_ring_next(ao_adc_head);
+		ao_wakeup((void *) &ao_adc_head);
+		ao_cpu_sleep_disable = 0;
+	}
+}
+
+void
+ao_adc_poll(void)
+{
+	ao_cpu_sleep_disable = 1;
+	ao_adc_channel = 0;
+	ao_adc_start();
+}
+
+void
+ao_adc_get(__xdata struct ao_adc *packet)
+{
+	uint8_t	i = ao_adc_ring_prev(ao_adc_head);
+	memcpy(packet, (void *) &ao_adc_ring[i], sizeof (struct ao_adc));
+}
+
+static void
+ao_adc_dump(void) __reentrant
+{
+	static __xdata struct ao_adc	packet;
+	uint8_t i;
+	printf ("interrupts: %u\n", ao_adc_int_count);
+	printf ("errors: %u\n", ao_adc_int_error);
+	ao_adc_get(&packet);
+	printf ("ADMUX %02x ADCSRA %02x ADCSRB %02x\n",
+		ADMUX, ADCSRA, ADCSRB);
+	printf("tick: %5u",  packet.tick);
+	for (i = 0; i < NUM_ADC; i++)
+		printf (" %5u", packet.adc[i]);
+	printf ("\n");
+}
+
+__code struct ao_cmds ao_adc_cmds[] = {
+	{ ao_adc_dump,	"a\0Display current ADC values" },
+	{ 0, NULL },
+};
+
+void
+ao_adc_init(void)
+{
+	DIDR0 = 0xf3;
+	DIDR2 = 0x3f;
+	ADCSRB = ADCSRB_INIT;
+	ADCSRA = ADCSRA_INIT;
+	ao_cmd_register(&ao_adc_cmds[0]);
+}
diff --git a/src-avr/ao_pins.h b/src-avr/ao_pins.h
index aec8994b..b927bc4b 100644
--- a/src-avr/ao_pins.h
+++ b/src-avr/ao_pins.h
@@ -263,6 +263,7 @@
 	#define USE_SERIAL_STDIN	1
 	#define HAS_SERIAL_1		1
 	#define HAS_USB			1
+	#define HAS_ADC			1
 	#define PACKET_HAS_SLAVE	0
 
 	#define AVR_VCC_5V	       	0
diff --git a/src-avr/ao_task.c b/src-avr/ao_task.c
index 51467133..aa3f85c7 100644
--- a/src-avr/ao_task.c
+++ b/src-avr/ao_task.c
@@ -26,6 +26,8 @@ __xdata struct ao_task *__data ao_cur_task;
 
 #ifdef AVR
 
+uint8_t	ao_cpu_sleep_disable;
+
 #define PUSH8(stack, val)	(*((stack)--) = (val))
 
 static void
@@ -200,7 +202,8 @@ ao_yield(void) __naked
 			/* Enter lower power mode when there isn't anything to do */
 			if (ao_next_task_index == ao_cur_task_index)
 #ifdef AVR
-				sleep_cpu();
+				if (!ao_cpu_sleep_disable)
+					sleep_cpu();
 #else
 				PCON = PCON_IDLE;
 #endif
diff --git a/src-avr/ao_telescience.c b/src-avr/ao_telescience.c
index 26e50ab3..5b047c16 100644
--- a/src-avr/ao_telescience.c
+++ b/src-avr/ao_telescience.c
@@ -31,6 +31,7 @@ main(void)
 	ao_spi_init();
 	ao_storage_init();
 	ao_usb_init();
+	ao_adc_init();
 
 	/* Turn on the LED until the system is stable */
 	ao_start_scheduler();
diff --git a/src-avr/telescience/Makefile b/src-avr/telescience/Makefile
index 2114b43d..1efa34f1 100644
--- a/src-avr/telescience/Makefile
+++ b/src-avr/telescience/Makefile
@@ -50,6 +50,7 @@ ALTOS_SRC = \
 	ao_timer.c \
 	ao_led.c \
 	ao_usb_avr.c \
+	ao_adc_avr.c \
 	$(TELESCIENCE_STORAGE)
 
 PRODUCT=TeleScience-v0.1