* 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;
-}
+volatile __data uint16_t ao_icp3_count;
static void
ao_pwmin_display(void) __reentrant
{
/* display the most recent value */
- printf("icp 3: %5u\n", ao_icp3());
+ printf("icp 3: %5u\n", ao_icp3_count);
}
-
-
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;
+ ao_icp3_count = (hi <<8) | lo;
}
__code struct ao_cmds ao_pwmin_cmds[] = {
(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 */
+ (4 << CS30)); /* clk/256 from prescaler */