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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 #define NUM_PA_HIST     16
  64
  65 #define SKIP_PA_HIST(i,j)       (((i) + (j)) & (NUM_PA_HIST - 1))
  66
  67 static uint32_t pa_hist[NUM_PA_HIST];
  68
  69 int
  70 main(void)
  71 {
  72         int16_t         sample_count;
  73         uint16_t        time;
  74         uint32_t        pa_interval_min, pa_interval_max;
  75         int32_t         pa_diff;
  76         uint8_t         h, i;
  77
  78         ao_led_init(LEDS_AVAILABLE);
  79         ao_timer_init();
  80
  81         /* Init external hardware */
  82         ao_spi_init();
  83         ao_ms5607_init();
  84         ao_ms5607_setup();
  85
  86         /* Give the person a second to get their finger out of the way */
  87         ao_delay(AO_MS_TO_TICKS(1000));
  88
  89         ao_log_micro_restore();
  90         ao_compute_height();
  91         ao_report_altitude();
  92         ao_pips();
  93         ao_log_micro_dump();
  94
  95         ao_delay(BOOST_DELAY);
  96         /* Wait for motion, averaging values to get ground pressure */
  97         time = ao_time();
  98         ao_pa_get();
  99         pa_avg = pa_ground = pa << FILTER_SHIFT;
 100         sample_count = 0;
 101         h = 0;
 102         for (;;) {
 103                 time += SAMPLE_SLEEP;
 104                 if (sample_count == 0)
 105                         ao_led_on(AO_LED_REPORT);
 106                 ao_delay_until(time);
 107                 ao_pa_get();
 108                 if (sample_count == 0)
 109                         ao_led_off(AO_LED_REPORT);
 110                 pa_hist[h] = pa;
 111                 h = SKIP_PA_HIST(h,1);
 112                 pa_avg = pa_avg - (pa_avg >> FILTER_SHIFT) + pa;
 113                 pa_diff = pa_ground - pa_avg;
 114
 115                 /* Check for a significant pressure change */
 116                 if (pa_diff > (BOOST_DETECT << FILTER_SHIFT))
 117                         break;
 118
 119                 if (sample_count < GROUND_AVG * 2) {
 120                         if (sample_count < GROUND_AVG)
 121                                 pa_sum += pa;
 122                         ++sample_count;
 123                 } else {
 124                         pa_ground = pa_sum >> (GROUND_AVG_SHIFT - FILTER_SHIFT);
 125                         pa_sum = 0;
 126                         sample_count = 0;
 127                 }
 128         }
 129
 130         pa_ground >>= FILTER_SHIFT;
 131
 132         /* Go back and find the first sample a decent interval above the ground */
 133         pa_min = pa_ground - LAND_DETECT;
 134         for (i = SKIP_PA_HIST(h,2); i != h; i = SKIP_PA_HIST(i,2)) {
 135                 if (pa_hist[i] < pa_min)
 136                         break;
 137         }
 138
 139         /* Log the remaining samples so we get a complete history since leaving the ground */
 140         for (; i != h; i = SKIP_PA_HIST(i,2)) {
 141                 pa = pa_hist[i];
 142                 ao_log_micro_data();
 143         }
 144
 145         /* Now sit around until the pressure is stable again and record the max */
 146
 147         sample_count = 0;
 148         pa_min = pa_avg;
 149         pa_interval_min = pa_avg;
 150         pa_interval_max = pa_avg;
 151         for (;;) {
 152                 time += SAMPLE_SLEEP;
 153                 ao_delay_until(time);
 154                 if ((sample_count & 3) == 0)
 155                         ao_led_on(AO_LED_REPORT);
 156                 ao_pa_get();
 157                 if ((sample_count & 3) == 0)
 158                         ao_led_off(AO_LED_REPORT);
 159                 if (sample_count & 1)
 160                         ao_log_micro_data();
 161                 pa_avg = pa_avg - (pa_avg >> FILTER_SHIFT) + pa;
 162                 if (pa_avg < pa_min)
 163                         pa_min = pa_avg;
 164
 165                 if (sample_count == (GROUND_AVG - 1)) {
 166                         pa_diff = pa_interval_max - pa_interval_min;
 167
 168                         /* Check to see if the pressure is now stable */
 169                         if (pa_diff < (LAND_DETECT << FILTER_SHIFT))
 170                                 break;
 171                         sample_count = 0;
 172                         pa_interval_min = pa_avg;
 173                         pa_interval_max = pa_avg;
 174                 } else {
 175                         if (pa_avg < pa_interval_min)
 176                                 pa_interval_min = pa_avg;
 177                         if (pa_avg > pa_interval_max)
 178                                 pa_interval_max = pa_avg;
 179                         ++sample_count;
 180                 }
 181         }
 182         pa_min >>= FILTER_SHIFT;
 183         ao_log_micro_save();
 184         ao_compute_height();
 185         ao_report_altitude();
 186         for (;;) {
 187                 cli();
 188                 set_sleep_mode(SLEEP_MODE_PWR_DOWN);
 189                 sleep_mode();
 190         }
 191 }