git.gag.com Git - fw/altos/blob - src/kernel/ao_microflight.c

   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_min;
  28
  29 static void
  30 ao_microsample(void)
  31 {
  32         ao_pa_get();
  33         ao_microkalman_predict();
  34         ao_microkalman_correct();
  35 }
  36
  37 #define NUM_PA_HIST     (GROUND_AVG)
  38
  39 #define SKIP_PA_HIST(i,j)       (((i) + (j)) & (NUM_PA_HIST - 1))
  40
  41 static uint32_t pa_hist[NUM_PA_HIST];
  42
  43 void
  44 ao_microflight(void)
  45 {
  46         int16_t         sample_count;
  47         int16_t         log_count;
  48         uint16_t        time;
  49         uint32_t        pa_interval_min, pa_interval_max;
  50         int32_t         pa_diff;
  51         uint8_t         h;
  52         uint8_t         i;
  53         uint8_t         accel_lock = 0;
  54         uint32_t        pa_sum = 0;
  55
  56         /* Wait for motion, averaging values to get ground pressure */
  57
  58         time = ao_time();
  59         ao_pa_get();
  60         ao_microkalman_init();
  61         pa_ground = pa;
  62         sample_count = 0;
  63         h = 0;
  64         for (;;) {
  65                 time += SAMPLE_SLEEP;
  66 #if BOOST_DETECT
  67                 if ((sample_count & 0x1f) == 0)
  68                         ao_led_on(AO_LED_REPORT);
  69 #endif
  70                 ao_delay_until(time);
  71                 ao_microsample();
  72 #if BOOST_DETECT
  73                 if ((sample_count & 0x1f) == 0)
  74                         ao_led_off(AO_LED_REPORT);
  75 #endif
  76                 pa_hist[h] = pa;
  77                 h = SKIP_PA_HIST(h,1);
  78                 pa_diff = pa_ground - ao_pa;
  79
  80 #if BOOST_DETECT
  81                 /* Check for a significant pressure change */
  82                 if (pa_diff > BOOST_DETECT)
  83                         break;
  84 #endif
  85
  86                 if (sample_count < GROUND_AVG * 2) {
  87                         if (sample_count < GROUND_AVG)
  88                                 pa_sum += pa;
  89                         ++sample_count;
  90                 } else {
  91                         pa_ground = pa_sum >> GROUND_AVG_SHIFT;
  92                         pa_sum = 0;
  93                         sample_count = 0;
  94 #if !BOOST_DETECT
  95                         break;
  96 #endif
  97                 }
  98         }
  99
 100         /* Go back and find the last sample close to the ground */
 101         pa_min = pa_ground - LAND_DETECT;
 102         for (i = SKIP_PA_HIST(h,-2); i != SKIP_PA_HIST(h,2); i = SKIP_PA_HIST(i,-2)) {
 103                 if (pa_hist[i] >= pa_min)
 104                         break;
 105         }
 106
 107         /* Log the remaining samples so we get a complete history since leaving the ground */
 108 #if LOG_INTERVAL < NUM_PA_HIST
 109         for (; i != h; i = SKIP_PA_HIST(i,2))
 110 #endif
 111         {
 112                 pa = pa_hist[i];
 113                 ao_log_micro_data();
 114         }
 115
 116         /* Now sit around until the pressure is stable again and record the max */
 117
 118         sample_count = 0;
 119         log_count = 0;
 120         pa_min = ao_pa;
 121         pa_interval_min = ao_pa;
 122         pa_interval_max = ao_pa;
 123         for (;;) {
 124                 time += SAMPLE_SLEEP;
 125                 ao_delay_until(time);
 126                 if ((sample_count & 3) == 0)
 127                         ao_led_on(AO_LED_REPORT);
 128                 ao_microsample();
 129                 if ((sample_count & 3) == 0)
 130                         ao_led_off(AO_LED_REPORT);
 131                 if (log_count == LOG_INTERVAL - 1) {
 132                         ao_log_micro_data();
 133                         log_count = 0;
 134                 } else
 135                         log_count++;
 136
 137                 /* If accelerating upwards, don't look for min pressure */
 138                 if (ao_pa_accel < ACCEL_LOCK_PA)
 139                         accel_lock = ACCEL_LOCK_TIME;
 140                 else if (accel_lock)
 141                         --accel_lock;
 142                 else if (ao_pa < pa_min)
 143                         pa_min = ao_pa;
 144
 145                 if (sample_count == (GROUND_AVG - 1)) {
 146                         pa_diff = pa_interval_max - pa_interval_min;
 147
 148                         /* Check to see if the pressure is now stable */
 149                         if (pa_diff < LAND_DETECT)
 150                                 break;
 151                         sample_count = 0;
 152                         pa_interval_min = ao_pa;
 153                         pa_interval_max = ao_pa;
 154                 } else {
 155                         if (ao_pa < pa_interval_min)
 156                                 pa_interval_min = ao_pa;
 157                         if (ao_pa > pa_interval_max)
 158                                 pa_interval_max = ao_pa;
 159                         ++sample_count;
 160                 }
 161         }
 162 }