Merge branch 'branch-1.2' into debian

1 files changed, 90 insertions, 0 deletions

diff --git a/src/avr/ao_pwmin.c b/src/avr/ao_pwmin.c
new file mode 100644
index 00000000..84397357
--- /dev/null
+++ b/src/avr/ao_pwmin.c
@@ -0,0 +1,90 @@
+/*
+ * Copyright © 2012 Robert D. Garbee <robert@gag.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"
+#include "ao_pwmin.h"
+
+/* 
+ * This code implements a PWM input using ICP3.  
+ *
+ * The initial use is to measure wind speed in the ULA/Ball summer intern 
+ * project payload developed at Challenger Middle School.  
+ */
+
+volatile __data uint16_t ao_icp3_count = 0;
+volatile __data uint16_t ao_icp3_last = 0;
+
+uint16_t ao_icp3(void)
+{
+	uint16_t	v;
+	ao_arch_critical(
+		v = ao_icp3_count;
+		);
+	return v;
+}
+
+static void
+ao_pwmin_display(void) __reentrant
+{
+	/* display the most recent value */
+	printf("icp 3: %5u\n", ao_icp3());
+
+}
+
+
+ISR(TIMER3_CAPT_vect)
+{
+	
+	uint8_t lo = ICR3L; 
+	uint8_t hi = ICR3H;
+	uint16_t ao_icp3_this = (hi <<8) | lo;
+	
+	/* handling counter rollovers */
+	if (ao_icp3_this >= ao_icp3_last)
+		ao_icp3_count = ao_icp3_this - ao_icp3_last;
+	else 
+		ao_icp3_count = ao_icp3_this + (65536 - ao_icp3_last);
+	ao_icp3_last = ao_icp3_this;
+}
+
+__code struct ao_cmds ao_pwmin_cmds[] = {
+	{ ao_pwmin_display,	"p\0PWM input" },
+	{ 0, NULL },
+};
+
+void
+ao_pwmin_init(void)
+{
+	/* do hardware setup here */
+	TCCR3A = ((0 << WGM31) |        /* normal mode, OCR3A */
+                  (0 << WGM30));        /* normal mode, OCR3A */
+        TCCR3B = ((1 << ICNC3) |        /* input capture noise canceler on */
+                  (0 << ICES3) |        /* input capture on falling edge (don't care) */
+                  (0 << WGM33) |        /* normal mode, OCR3A */
+                  (0 << WGM32) |        /* normal mode, OCR3A */
+                  (3 << CS30));         /* clk/64 from prescaler */
+
+    	
+
+        TIMSK3 = (1 << ICIE3);         /* Interrupt on input compare */
+
+		/* set the spike filter bit in the TCCR3B register */
+
+	ao_cmd_register(&ao_pwmin_cmds[0]);
+}
+
+