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   1 /*
   2  * Copyright © 2013 Keith Packard <keithp@keithp.com>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along
  15  * with this program; if not, write to the Free Software Foundation, Inc.,
  16  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  17  */
  18
  19 #ifndef AO_FLIGHT_TEST
  20 #include <ao.h>
  21 #endif
  22 #include <ao_micropeak.h>
  23 #include <ao_log_micro.h>
  24
  25 uint32_t        pa;
  26 uint32_t        pa_ground;
  27 uint32_t        pa_ground_next;
  28 uint32_t        pa_min;
  29
  30 static void
  31 ao_microsample(void)
  32 {
  33         ao_pa_get();
  34         ao_microkalman_predict();
  35         ao_microkalman_correct();
  36 }
  37
  38 #define NUM_PA_HIST     (GROUND_AVG)
  39
  40 #define SKIP_PA_HIST(i,j)       (((i) + (j)) & (NUM_PA_HIST - 1))
  41
  42 static uint32_t pa_hist[NUM_PA_HIST];
  43
  44 void
  45 ao_microflight(void)
  46 {
  47         int16_t         sample_count;
  48         int16_t         log_count;
  49         AO_TICK_TYPE    time;
  50         uint32_t        pa_interval_min, pa_interval_max;
  51         int32_t         pa_diff;
  52         uint8_t         h;
  53         uint8_t         i;
  54         uint8_t         accel_lock = 0;
  55         uint32_t        pa_sum = 0;
  56
  57         /* Wait for motion, averaging values to get ground pressure */
  58
  59         time = ao_time();
  60         ao_pa_get();
  61         ao_microkalman_init();
  62         pa_ground_next = pa_ground = pa;
  63         sample_count = 0;
  64         h = 0;
  65         for (;;) {
  66                 time += SAMPLE_SLEEP;
  67 #if BOOST_DETECT
  68                 if ((sample_count & 0x1f) == 0)
  69                         ao_led_on(AO_LED_REPORT);
  70 #endif
  71                 ao_delay_until(time);
  72                 ao_microsample();
  73 #if BOOST_DETECT
  74                 if ((sample_count & 0x1f) == 0)
  75                         ao_led_off(AO_LED_REPORT);
  76 #endif
  77                 pa_hist[h] = pa;
  78                 h = SKIP_PA_HIST(h,1);
  79                 pa_diff = (int32_t) (pa_ground - ao_pa);
  80
  81 #if BOOST_DETECT
  82                 /* Check for a significant pressure change */
  83                 if (pa_diff > BOOST_DETECT)
  84                         break;
  85 #endif
  86
  87                 if (sample_count < GROUND_AVG * 2) {
  88                         if (sample_count < GROUND_AVG)
  89                                 pa_sum += pa;
  90                         ++sample_count;
  91                 } else {
  92                         pa_ground = pa_ground_next;
  93                         pa_ground_next = pa_sum >> GROUND_AVG_SHIFT;
  94                         pa_sum = 0;
  95                         sample_count = 0;
  96 #if !BOOST_DETECT
  97                         break;
  98 #endif
  99                 }
 100         }
 101
 102         /* Go back and find the last sample close to the ground */
 103         pa_min = pa_ground - LAND_DETECT;
 104         for (i = SKIP_PA_HIST(h,-2); i != SKIP_PA_HIST(h,2); i = SKIP_PA_HIST(i,-2)) {
 105                 if (pa_hist[i] >= pa_min)
 106                         break;
 107         }
 108
 109         /* Log the remaining samples so we get a complete history since leaving the ground */
 110 #if LOG_INTERVAL < NUM_PA_HIST
 111         for (; i != h; i = SKIP_PA_HIST(i,2))
 112 #endif
 113         {
 114                 pa = pa_hist[i];
 115                 ao_log_micro_data();
 116         }
 117
 118         /* Now sit around until the pressure is stable again and record the max */
 119
 120         sample_count = 0;
 121         log_count = 0;
 122         pa_min = ao_pa;
 123         pa_interval_min = ao_pa;
 124         pa_interval_max = ao_pa;
 125         for (;;) {
 126                 time += SAMPLE_SLEEP;
 127                 ao_delay_until(time);
 128                 if ((sample_count & 3) == 0)
 129                         ao_led_on(AO_LED_REPORT);
 130                 ao_microsample();
 131                 if ((sample_count & 3) == 0)
 132                         ao_led_off(AO_LED_REPORT);
 133                 if (log_count == LOG_INTERVAL - 1) {
 134                         ao_log_micro_data();
 135                         log_count = 0;
 136                 } else
 137                         log_count++;
 138
 139                 /* If accelerating upwards, don't look for min pressure */
 140                 if (ao_pa_accel < ACCEL_LOCK_PA)
 141                         accel_lock = ACCEL_LOCK_TIME;
 142                 else if (accel_lock)
 143                         --accel_lock;
 144                 else if (ao_pa < pa_min)
 145                         pa_min = ao_pa;
 146
 147                 if (sample_count == (GROUND_AVG - 1)) {
 148                         pa_diff = (int32_t) (pa_interval_max - pa_interval_min);
 149
 150                         /* Check to see if the pressure is now stable */
 151                         if (pa_diff < LAND_DETECT)
 152                                 break;
 153                         sample_count = 0;
 154                         pa_interval_min = ao_pa;
 155                         pa_interval_max = ao_pa;
 156                 } else {
 157                         if (ao_pa < pa_interval_min)
 158                                 pa_interval_min = ao_pa;
 159                         if (ao_pa > pa_interval_max)
 160                                 pa_interval_max = ao_pa;
 161                         ++sample_count;
 162                 }
 163         }
 164 }