ICP3 working

[fw/altos] / src / avr / ao_pwmin.c

diff --git a/src/avr/ao_pwmin.c b/src/avr/ao_pwmin.c
index 4d96404dca1b07af8850cfa651506e09ec92910d..73a153b2e4cc67332b879e18b02febe1333687c5 100644 (file)
--- a/src/avr/ao_pwmin.c
+++ b/src/avr/ao_pwmin.c
@@ -25,17 +25,21 @@
  * project payload developed at Challenger Middle School.  
  */
 
+volatile __data uint16_t ao_icp3_count;
+
 static void
 ao_pwmin_display(void) __reentrant
 {
-       uint8_t lo = TCNT1L; 
-       uint8_t hi = TCNT1H;
-       uint16_t value = (hi <<8) | lo;
-
-       /* now display the value we read */
-       printf("timer 1: %5u",  value);
+       /* display the most recent value */
+       printf("icp 3: %5u\n", ao_icp3_count);
 
 }
+ISR(TIMER3_CAPT_vect)
+{
+       uint8_t lo = ICR3L; 
+       uint8_t hi = ICR3H;
+       ao_icp3_count = (hi <<8) | lo;
+}
 
 __code struct ao_cmds ao_pwmin_cmds[] = {
        { ao_pwmin_display,     "p\0PWM input" },
@@ -46,6 +50,18 @@ 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 */
+                  (4 << CS30));         /* clk/256 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]);