Paparazzi UAS  v4.2.2_stable-4-gcc32f65
Paparazzi is a free software Unmanned Aircraft System.
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baro_board.c
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1  /*
2  * Copyright (C) 2010 ENAC
3  *
4  * This file is part of paparazzi.
5  *
6  * paparazzi is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 2, or (at your option)
9  * any later version.
10  *
11  * paparazzi is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with paparazzi; see the file COPYING. If not, write to
18  * the Free Software Foundation, 59 Temple Place - Suite 330,
19  * Boston, MA 02111-1307, USA.
20  *
21  */
22 
23 
24 /* driver for the analog Barometer Mpxa6115 using ADC ads1114 (16 bits I2C 860SpS max) from Texas instruments
25  * Navarro & Gorraz & Hattenberger
26  */
27 
29 
30 
31 /* Common Baro struct */
32 struct Baro baro;
33 
34 #if USE_BARO_AS_ALTIMETER
35 /* Number of values to compute an offset at startup */
36 #define OFFSET_NBSAMPLES_AVRG 100
37 
38 /* Weight for offset IIR filter */
39 #define OFFSET_FILTER 7
40 
41 float baro_alt;
42 float baro_alt_offset;
44 #endif
45 
46 void baro_init( void ) {
47  ads1114_init();
49  baro.absolute = 0;
50  baro.differential = 0; /* not handled on this board, use extra module (ex: airspeed_ads1114) */
51 #if USE_BARO_AS_ALTIMETER
52  baro_alt = 0.;
53  baro_alt_offset = 0.;
55 #endif
56 }
57 
58 void baro_periodic( void ) {
59 
60 #if USE_BARO_AS_ALTIMETER
61  if (baro.status == BS_UNINITIALIZED && BARO_ABS_ADS.data_available) {
62  // IIR filter to compute an initial offset
63  baro_alt_offset = (OFFSET_FILTER * baro_alt_offset + (float)baro.absolute) / (OFFSET_FILTER + 1);
64  // decrease init counter
65  --offset_cnt;
66  if (offset_cnt == 0) baro.status = BS_RUNNING;
67  }
68 #endif
69  // Read the ADC
71 }
72 
unsigned short uint16_t
Definition: types.h:16
Definition: baro.h:41
#define OFFSET_NBSAMPLES_AVRG
void baro_periodic(void)
Definition: baro_board.c:56
float baro_alt
void ads1114_read(struct ads1114_periph *p)
Definition: ads1114.c:62
void ads1114_init(void)
Definition: ads1114.c:37
int32_t absolute
Definition: baro.h:42
struct Baro baro
Definition: baro_board.c:34
int32_t differential
Definition: baro.h:43
void baro_init(void)
Definition: baro_board.c:38
uint16_t offset_cnt
enum BaroStatus status
Definition: baro.h:44
#define BARO_ABS_ADS
Definition: baro_board.h:49