altos: Rename 'core' to 'kernel'

[fw/altos] / src / kernel / ao_microflight.c

diff --git a/src/kernel/ao_microflight.c b/src/kernel/ao_microflight.c
new file mode 100644 (file)
index 0000000..f680e40
--- /dev/null
+++ b/src/kernel/ao_microflight.c
@@ -0,0 +1,143 @@
+/*
+ * 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;
+               }
+       }
+}