+/*
+ * Copyright © 2013 Keith Packard <keithp@keithp.com>
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ */
+
+#ifndef AO_FLIGHT_TEST
+#include <ao.h>
+#endif
+#include <ao_micropeak.h>
+#include <ao_log_micro.h>
+
+uint32_t pa;
+uint32_t pa_ground;
+uint32_t pa_min;
+
+static void
+ao_microsample(void)
+{
+ ao_pa_get();
+ ao_microkalman_predict();
+ ao_microkalman_correct();
+}
+
+#define NUM_PA_HIST (GROUND_AVG)
+
+#define SKIP_PA_HIST(i,j) (((i) + (j)) & (NUM_PA_HIST - 1))
+
+static uint32_t pa_hist[NUM_PA_HIST];
+
+void
+ao_microflight(void)
+{
+ int16_t sample_count;
+ uint16_t time;
+ uint32_t pa_interval_min, pa_interval_max;
+ int32_t pa_diff;
+ uint8_t h, i;
+ uint8_t accel_lock = 0;
+ uint32_t pa_sum = 0;
+
+ /* Wait for motion, averaging values to get ground pressure */
+
+ time = ao_time();
+ ao_pa_get();
+ ao_microkalman_init();
+ pa_ground = pa;
+ sample_count = 0;
+ h = 0;
+ for (;;) {
+ time += SAMPLE_SLEEP;
+ if ((sample_count & 0x1f) == 0)
+ ao_led_on(AO_LED_REPORT);
+ ao_delay_until(time);
+ ao_microsample();
+ if ((sample_count & 0x1f) == 0)
+ ao_led_off(AO_LED_REPORT);
+ pa_hist[h] = pa;
+ h = SKIP_PA_HIST(h,1);
+ pa_diff = pa_ground - ao_pa;
+
+ /* Check for a significant pressure change */
+ if (pa_diff > BOOST_DETECT)
+ break;
+
+ if (sample_count < GROUND_AVG * 2) {
+ if (sample_count < GROUND_AVG)
+ pa_sum += pa;
+ ++sample_count;
+ } else {
+ pa_ground = pa_sum >> GROUND_AVG_SHIFT;
+ pa_sum = 0;
+ sample_count = 0;
+ }
+ }
+
+ /* Go back and find the last sample close to the ground */
+ pa_min = pa_ground - LAND_DETECT;
+ for (i = SKIP_PA_HIST(h,-2); i != SKIP_PA_HIST(h,2); i = SKIP_PA_HIST(i,-2)) {
+ if (pa_hist[i] >= pa_min)
+ break;
+ }
+
+ /* Log the remaining samples so we get a complete history since leaving the ground */
+ for (; i != h; i = SKIP_PA_HIST(i,2)) {
+ pa = pa_hist[i];
+ ao_log_micro_data();
+ }
+
+ /* Now sit around until the pressure is stable again and record the max */
+
+ sample_count = 0;
+ pa_min = ao_pa;
+ pa_interval_min = ao_pa;
+ pa_interval_max = ao_pa;
+ for (;;) {
+ time += SAMPLE_SLEEP;
+ ao_delay_until(time);
+ if ((sample_count & 3) == 0)
+ ao_led_on(AO_LED_REPORT);
+ ao_microsample();
+ if ((sample_count & 3) == 0)
+ ao_led_off(AO_LED_REPORT);
+ if (sample_count & 1)
+ ao_log_micro_data();
+
+ /* If accelerating upwards, don't look for min pressure */
+ if (ao_pa_accel < ACCEL_LOCK_PA)
+ accel_lock = ACCEL_LOCK_TIME;
+ else if (accel_lock)
+ --accel_lock;
+ else if (ao_pa < pa_min)
+ pa_min = ao_pa;
+
+ if (sample_count == (GROUND_AVG - 1)) {
+ pa_diff = pa_interval_max - pa_interval_min;
+
+ /* Check to see if the pressure is now stable */
+ if (pa_diff < LAND_DETECT)
+ break;
+ sample_count = 0;
+ pa_interval_min = ao_pa;
+ pa_interval_max = ao_pa;
+ } else {
+ if (ao_pa < pa_interval_min)
+ pa_interval_min = ao_pa;
+ if (ao_pa > pa_interval_max)
+ pa_interval_max = ao_pa;
+ ++sample_count;
+ }
+ }
+}