X-Git-Url: https://git.gag.com/?p=fw%2Faltos;a=blobdiff_plain;f=src%2Favr%2Fao_pwmin.c;h=84397357a7ee89ee4967b3300f0e2b49950cb62f;hp=4d96404dca1b07af8850cfa651506e09ec92910d;hb=2427eae5f3b429d302fbe14f708dcbc68c851954;hpb=3ccc4a13e3f76bec864d61b0cdfd57c76c6baadb

diff --git a/src/avr/ao_pwmin.c b/src/avr/ao_pwmin.c
index 4d96404d..84397357 100644
--- a/src/avr/ao_pwmin.c
+++ b/src/avr/ao_pwmin.c
@@ -25,16 +25,40 @@
  * 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
 {
-	uint8_t lo = TCNT1L; 
-	uint8_t hi = TCNT1H;
-	uint16_t value = (hi <<8) | lo;
+	/* display the most recent value */
+	printf("icp 3: %5u\n", ao_icp3());
+
+}
 
-	/* now display the value we read */
-	printf("timer 1: %5u",  value);
 
+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[] = {
@@ -46,6 +70,18 @@ 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]);