X-Git-Url: https://git.gag.com/?p=fw%2Faltos;a=blobdiff_plain;f=src%2Favr%2Fao_pwmin.c;h=84397357a7ee89ee4967b3300f0e2b49950cb62f;hp=edcb163641cea8a1aa28db542e787d4f9650f892;hb=3fe932206f40f4d6f83a4ef49e064109a7a3de92;hpb=49b1ff4c614d24977b33cd17b583acc87acff476

diff --git a/src/avr/ao_pwmin.c b/src/avr/ao_pwmin.c
index edcb1636..84397357 100644
--- a/src/avr/ao_pwmin.c
+++ b/src/avr/ao_pwmin.c
@@ -25,27 +25,40 @@
  * project payload developed at Challenger Middle School.  
  */
 
-volatile __data uint16_t ao_tick3_count;
+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());
 
-	uint8_t lo3 = TCNT3L; 
-	uint8_t hi3 = TCNT3H;
-	uint16_t value3 = (hi3 <<8) | lo3;
+}
 
-	/* now display the value we read */
-	printf("timer 1: %5u %2x %2x\n", value, hi, lo);
-	printf("timer 3: %5u %2x %2x\n", value3, hi3, lo3);
 
-}
-ISR(TIMER3_COMPA_vect)
+ISR(TIMER3_CAPT_vect)
 {
-        ++ao_tick3_count;
+	
+	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[] = {
@@ -59,15 +72,15 @@ ao_pwmin_init(void)
 	/* do hardware setup here */
 	TCCR3A = ((0 << WGM31) |        /* normal mode, OCR3A */
                   (0 << WGM30));        /* normal mode, OCR3A */
-        TCCR3B = ((0 << ICNC3) |        /* no input capture noise canceler */
+        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 */
-                  (4 << CS30));         /* clk/256 from prescaler */
+                  (3 << CS30));         /* clk/64 from prescaler */
 
-        OCR3A = 1250;                   /* 8MHz clock */
+    	
 
-        TIMSK3 = (1 << OCIE3A);         /* Interrupt on compare match */
+        TIMSK3 = (1 << ICIE3);         /* Interrupt on input compare */
 
 		/* set the spike filter bit in the TCCR3B register */