altos: Add battery voltage sampling driver

For devices without a full ADC compliment, this just samples the
battery pin and converts to mV.

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

1 files changed, 60 insertions, 0 deletions

diff --git a/src/cc1111/ao_battery.c b/src/cc1111/ao_battery.c
new file mode 100644
index 00000000..070f682f
--- /dev/null
+++ b/src/cc1111/ao_battery.c
@@ -0,0 +1,60 @@
+/*
+ * 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"
+static __data union {
+	uint8_t	d[2];
+	int16_t	v;
+} ao_battery_value;
+
+void
+ao_battery_isr(void) ao_arch_interrupt(1)
+{
+	ao_battery_value.d[0] = ADCL;
+	ao_battery_value.d[1] = ADCH;
+	ao_wakeup(DATA_TO_XDATA(&ao_battery_value));
+}
+
+uint16_t
+ao_battery_get(void) 
+{
+	ao_arch_critical(
+		ADCCON3 = ADCCON3_EREF_VDD | ADCCON3_EDIV_512 | BATTERY_PIN;
+		ao_sleep(DATA_TO_XDATA(&ao_battery_value));
+		);
+	return (uint16_t) ((int32_t) ao_battery_value.v * (int32_t) 3333 >> 15);
+}
+
+static void
+ao_battery_show(void)
+{
+	printf("Battery: %u mV\n", ao_battery_get());
+}
+
+__code struct ao_cmds ao_battery_cmds[] = {
+	{ ao_battery_show,	"B\0Show battery voltage" },
+	{ 0, NULL },
+};
+
+void
+ao_battery_init(void)
+{
+	ADCCFG = (1 << BATTERY_PIN);
+	ADCIF = 0;
+	IEN0 |= IEN0_ADCIE;
+	ao_cmd_register(&ao_battery_cmds[0]);
+}