*
* 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.
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* 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[] = {
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]);