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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 #include <ao_async.h>
  23
  24 static struct ao_ms5607_sample  sample;
  25 static struct ao_ms5607_value   value;
  26
  27 uint32_t        pa;
  28 uint32_t        pa_avg;
  29 uint32_t        pa_ground;
  30 uint32_t        pa_min;
  31 alt_t           ground_alt, max_alt;
  32 alt_t           ao_max_height;
  33
  34 static uint32_t pa_sum;
  35
  36 static void
  37 ao_pa_get(void)
  38 {
  39         ao_ms5607_sample(&sample);
  40         ao_ms5607_convert(&sample, &value);
  41         pa = value.pres;
  42 }
  43
  44 static void
  45 ao_compute_height(void)
  46 {
  47         ground_alt = ao_pa_to_altitude(pa_ground);
  48         max_alt = ao_pa_to_altitude(pa_min);
  49         ao_max_height = max_alt - ground_alt;
  50 }
  51
  52 static void
  53 ao_pips(void)
  54 {
  55         uint8_t i;
  56         for (i = 0; i < 10; i++) {
  57                 ao_led_toggle(AO_LED_REPORT);
  58                 ao_delay(AO_MS_TO_TICKS(80));
  59         }
  60         ao_delay(AO_MS_TO_TICKS(200));
  61 }
  62
  63 int
  64 main(void)
  65 {
  66         int16_t         sample_count;
  67         uint16_t        time;
  68         uint32_t        pa_interval_min, pa_interval_max;
  69         int32_t         pa_diff;
  70
  71         ao_led_init(LEDS_AVAILABLE);
  72         ao_timer_init();
  73
  74         /* Init external hardware */
  75         ao_spi_init();
  76         ao_ms5607_init();
  77         ao_ms5607_setup();
  78
  79         /* Give the person a second to get their finger out of the way */
  80         ao_delay(AO_MS_TO_TICKS(1000));
  81
  82         ao_log_micro_restore();
  83         ao_compute_height();
  84         ao_report_altitude();
  85         ao_pips();
  86         ao_log_micro_dump();
  87
  88         ao_delay(BOOST_DELAY);
  89         /* Wait for motion, averaging values to get ground pressure */
  90         time = ao_time();
  91         ao_pa_get();
  92         pa_avg = pa_ground = pa << FILTER_SHIFT;
  93         sample_count = 0;
  94         for (;;) {
  95                 time += SAMPLE_SLEEP;
  96                 if (sample_count == 0)
  97                         ao_led_on(AO_LED_REPORT);
  98                 ao_delay_until(time);
  99                 ao_pa_get();
 100                 if (sample_count == 0)
 101                         ao_led_off(AO_LED_REPORT);
 102                 pa_avg = pa_avg - (pa_avg >> FILTER_SHIFT) + pa;
 103                 pa_diff = pa_ground - pa_avg;
 104
 105                 /* Check for a significant pressure change */
 106                 if (pa_diff > (BOOST_DETECT << FILTER_SHIFT))
 107                         break;
 108
 109                 if (sample_count < GROUND_AVG * 2) {
 110                         if (sample_count < GROUND_AVG)
 111                                 pa_sum += pa;
 112                         ++sample_count;
 113                 } else {
 114                         pa_ground = pa_sum >> (GROUND_AVG_SHIFT - FILTER_SHIFT);
 115                         pa_sum = 0;
 116                         sample_count = 0;
 117                 }
 118         }
 119
 120         pa_ground >>= FILTER_SHIFT;
 121
 122         /* Now sit around until the pressure is stable again and record the max */
 123
 124         sample_count = 0;
 125         pa_min = pa_avg;
 126         pa_interval_min = pa_avg;
 127         pa_interval_max = pa_avg;
 128         for (;;) {
 129                 time += SAMPLE_SLEEP;
 130                 ao_delay_until(time);
 131                 if ((sample_count & 3) == 0)
 132                         ao_led_on(AO_LED_REPORT);
 133                 ao_pa_get();
 134                 if ((sample_count & 3) == 0)
 135                         ao_led_off(AO_LED_REPORT);
 136                 if (sample_count & 1)
 137                         ao_log_micro_data();
 138                 pa_avg = pa_avg - (pa_avg >> FILTER_SHIFT) + pa;
 139                 if (pa_avg < pa_min)
 140                         pa_min = pa_avg;
 141
 142                 if (sample_count == (GROUND_AVG - 1)) {
 143                         pa_diff = pa_interval_max - pa_interval_min;
 144
 145                         /* Check to see if the pressure is now stable */
 146                         if (pa_diff < (LAND_DETECT << FILTER_SHIFT))
 147                                 break;
 148                         sample_count = 0;
 149                         pa_interval_min = pa_avg;
 150                         pa_interval_max = pa_avg;
 151                 } else {
 152                         if (pa_avg < pa_interval_min)
 153                                 pa_interval_min = pa_avg;
 154                         if (pa_avg > pa_interval_max)
 155                                 pa_interval_max = pa_avg;
 156                         ++sample_count;
 157                 }
 158         }
 159         pa_min >>= FILTER_SHIFT;
 160         ao_log_micro_save();
 161         ao_compute_height();
 162         ao_report_altitude();
 163         for (;;) {
 164                 cli();
 165                 set_sleep_mode(SLEEP_MODE_PWR_DOWN);
 166                 sleep_mode();
 167         }
 168 }