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   1 /*
   2  * Copyright © 2012 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; version 2 of the License.
   7  *
   8  * This program is distributed in the hope that it will be useful, but
   9  * WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  16  */
  17
  18 #include <ao.h>
  19 #include <ao_micropeak.h>
  20 #include <ao_ms5607.h>
  21 #include <ao_log_micro.h>
  22
  23 static struct ao_ms5607_sample  sample;
  24 static struct ao_ms5607_value   value;
  25
  26 uint32_t        pa;
  27 uint32_t        pa_avg;
  28 uint32_t        pa_ground;
  29 uint32_t        pa_min;
  30 alt_t           ground_alt, max_alt;
  31 alt_t           ao_max_height;
  32
  33 static uint32_t pa_sum;
  34
  35 static void
  36 ao_pa_get(void)
  37 {
  38         ao_ms5607_sample(&sample);
  39         ao_ms5607_convert(&sample, &value);
  40         pa = value.pres;
  41 }
  42
  43 static void
  44 ao_compute_height(void)
  45 {
  46         ground_alt = ao_pa_to_altitude(pa_ground);
  47         max_alt = ao_pa_to_altitude(pa_min);
  48         ao_max_height = max_alt - ground_alt;
  49 }
  50
  51 int
  52 main(void)
  53 {
  54         int16_t         sample_count;
  55         uint16_t        time;
  56         uint32_t        pa_interval_min, pa_interval_max;
  57         int32_t         pa_diff;
  58
  59         ao_led_init(LEDS_AVAILABLE);
  60         ao_timer_init();
  61
  62         /* Init external hardware */
  63         ao_spi_init();
  64         ao_ms5607_init();
  65         ao_ms5607_setup();
  66
  67         /* Give the person a second to get their finger out of the way */
  68         ao_delay(AO_MS_TO_TICKS(1000));
  69
  70         ao_log_micro_restore();
  71         ao_compute_height();
  72         ao_report_altitude();
  73         ao_log_micro_dump();
  74
  75         ao_delay(BOOST_DELAY);
  76         /* Wait for motion, averaging values to get ground pressure */
  77         time = ao_time();
  78         ao_pa_get();
  79         pa_avg = pa_ground = pa << FILTER_SHIFT;
  80         sample_count = 0;
  81         for (;;) {
  82                 time += SAMPLE_SLEEP;
  83                 if (sample_count == 0)
  84                         ao_led_on(AO_LED_REPORT);
  85                 ao_delay_until(time);
  86                 ao_pa_get();
  87                 if (sample_count == 0)
  88                         ao_led_off(AO_LED_REPORT);
  89                 pa_avg = pa_avg - (pa_avg >> FILTER_SHIFT) + pa;
  90                 pa_diff = pa_ground - pa_avg;
  91
  92                 /* Check for a significant pressure change */
  93                 if (pa_diff > (BOOST_DETECT << FILTER_SHIFT))
  94                         break;
  95
  96                 if (sample_count < GROUND_AVG * 2) {
  97                         if (sample_count < GROUND_AVG)
  98                                 pa_sum += pa;
  99                         ++sample_count;
 100                 } else {
 101                         pa_ground = pa_sum >> (GROUND_AVG_SHIFT - FILTER_SHIFT);
 102                         pa_sum = 0;
 103                         sample_count = 0;
 104                 }
 105         }
 106
 107         pa_ground >>= FILTER_SHIFT;
 108
 109         /* Now sit around until the pressure is stable again and record the max */
 110
 111         sample_count = 0;
 112         pa_min = pa_avg;
 113         pa_interval_min = pa_avg;
 114         pa_interval_max = pa_avg;
 115         for (;;) {
 116                 time += SAMPLE_SLEEP;
 117                 ao_delay_until(time);
 118                 if ((sample_count & 3) == 0)
 119                         ao_led_on(AO_LED_REPORT);
 120                 ao_pa_get();
 121                 if ((sample_count & 3) == 0)
 122                         ao_led_off(AO_LED_REPORT);
 123                 if (sample_count & 1)
 124                         ao_log_micro_data();
 125                 pa_avg = pa_avg - (pa_avg >> FILTER_SHIFT) + pa;
 126                 if (pa_avg < pa_min)
 127                         pa_min = pa_avg;
 128
 129                 if (sample_count == (GROUND_AVG - 1)) {
 130                         pa_diff = pa_interval_max - pa_interval_min;
 131
 132                         /* Check to see if the pressure is now stable */
 133                         if (pa_diff < (LAND_DETECT << FILTER_SHIFT))
 134                                 break;
 135                         sample_count = 0;
 136                         pa_interval_min = pa_avg;
 137                         pa_interval_max = pa_avg;
 138                 } else {
 139                         if (pa_avg < pa_interval_min)
 140                                 pa_interval_min = pa_avg;
 141                         if (pa_avg > pa_interval_max)
 142                                 pa_interval_max = pa_avg;
 143                         ++sample_count;
 144                 }
 145         }
 146         pa_min >>= FILTER_SHIFT;
 147         ao_log_micro_save();
 148         ao_compute_height();
 149         ao_report_altitude();
 150         for (;;) {
 151                 cli();
 152                 set_sleep_mode(SLEEP_MODE_PWR_DOWN);
 153                 sleep_mode();
 154         }
 155 }