1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
|
/*
* spreadspace avr utils
*
*
* Copyright (C) 2016 Bernhard Tittelbach <bernhard@tittelbach.org>
* appreciative nod to Adafruit for writing a great example, go buy their stuff
*
* This file is part of spreadspace avr utils.
*
* spreadspace avr utils is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* any later version.
*
* spreadspace avr utils is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with spreadspace avr utils. If not, see <http://www.gnu.org/licenses/>.
*/
#include <stdio.h>
#include <avr/pgmspace.h>
#include <LUFA/Drivers/Peripheral/SPI.h>
#include "bmp280.h"
int32_t bmp280_t_fine = 0;
void bmp280_cs(bmp280_sensor *sensor, uint8_t select)
{
if (!select)
*(sensor->cs_port) |= _BV(sensor->cs_pin);
else
*(sensor->cs_port) &= ~ _BV(sensor->cs_pin);
}
void bmp280_write8(uint8_t reg, uint8_t value)
{
SPI_SendByte(reg & ~0x80); //bit 7 needs to be low for write mode
SPI_SendByte(value);
}
uint8_t bmp280_read8(uint8_t reg)
{
SPI_SendByte(reg | 0x80); //bit 7 high for read mode
return SPI_ReceiveByte();
}
uint16_t bmp280_read16(uint8_t reg)
{
uint16_t value = 0;
SPI_SendByte(reg | 0x80); //bit 7 high for read mode
value |= ((uint16_t) SPI_ReceiveByte() & 0xFF) << 8;
value |= (uint16_t) SPI_ReceiveByte() & 0xFF;
return value;
}
uint32_t bmp280_read24(uint8_t reg)
{
uint32_t value = 0;
SPI_SendByte(reg | 0x80); //bit 7 high for read mode
value |= ((uint32_t) SPI_ReceiveByte() & 0xFF) << 16;
value |= ((uint32_t) SPI_ReceiveByte() & 0xFF) << 8;
value |= (uint32_t) SPI_ReceiveByte() & 0xFF;
return value;
}
int16_t bmp280_readS16(uint8_t reg)
{
return (int16_t) bmp280_read16(reg);
}
uint16_t bmp280_read16_LE(uint8_t reg)
{
uint16_t value = 0;
SPI_SendByte(reg | 0x80); //bit 7 high for read mode
value |= (uint16_t) SPI_ReceiveByte() & 0xFF;
value |= ((uint16_t) SPI_ReceiveByte() & 0xFF) << 8;
return value;
}
int16_t bmp280_readS16_LE(uint8_t reg)
{
return (int16_t)bmp280_read16_LE(reg);
}
void bmp280_readCoefficients(bmp280_sensor *sensor)
{
bmp280_cs(sensor, true);
sensor->dig_T1 = bmp280_read16_LE(BMP280_REGISTER_DIG_T1);
sensor->dig_T2 = bmp280_readS16_LE(BMP280_REGISTER_DIG_T2);
sensor->dig_T3 = bmp280_readS16_LE(BMP280_REGISTER_DIG_T3);
sensor->dig_P1 = bmp280_read16_LE(BMP280_REGISTER_DIG_P1);
sensor->dig_P2 = bmp280_readS16_LE(BMP280_REGISTER_DIG_P2);
sensor->dig_P3 = bmp280_readS16_LE(BMP280_REGISTER_DIG_P3);
sensor->dig_P4 = bmp280_readS16_LE(BMP280_REGISTER_DIG_P4);
sensor->dig_P5 = bmp280_readS16_LE(BMP280_REGISTER_DIG_P5);
sensor->dig_P6 = bmp280_readS16_LE(BMP280_REGISTER_DIG_P6);
sensor->dig_P7 = bmp280_readS16_LE(BMP280_REGISTER_DIG_P7);
sensor->dig_P8 = bmp280_readS16_LE(BMP280_REGISTER_DIG_P8);
sensor->dig_P9 = bmp280_readS16_LE(BMP280_REGISTER_DIG_P9);
bmp280_cs(sensor, false);
}
//need to init SPI beforehand
void bmp280_init(bmp280_sensor *sensor, volatile uint8_t *cs_port, uint8_t cs_pin)
{
memset(sensor,0,sizeof(bmp280_sensor));
sensor->cs_port = cs_port;
sensor->cs_pin = cs_pin;
bmp280_readCoefficients(sensor);
}
float bmp280_readTemp(bmp280_sensor *sensor)
{
int32_t var1, var2;
bmp280_cs(sensor, true);
int32_t adc_T = bmp280_read24(BMP280_REGISTER_TEMPDATA);
bmp280_cs(sensor, false);
adc_T >>= 4;
var1 = ((((adc_T>>3) - ((int32_t)sensor->dig_T1 <<1))) *
((int32_t)sensor->dig_T2)) >> 11;
var2 = (((((adc_T>>4) - ((int32_t)sensor->dig_T1)) *
((adc_T>>4) - ((int32_t)sensor->dig_T1))) >> 12) *
((int32_t)sensor->dig_T3)) >> 14;
bmp280_t_fine = var1 + var2;
float T = (bmp280_t_fine * 5 + 128) >> 8;
return T/100;
}
float bmp280_readPressure(bmp280_sensor *sensor)
{
int64_t var1, var2, p;
// Must be done first to get the bmp280_t_fine variable
bmp280_readTemp(sensor);
bmp280_cs(sensor, true);
int32_t adc_P = bmp280_read24(BMP280_REGISTER_PRESSUREDATA);
bmp280_cs(sensor, false);
adc_P >>= 4;
var1 = ((int64_t)bmp280_t_fine) - 128000;
var2 = var1 * var1 * (int64_t)sensor->dig_P6;
var2 = var2 + ((var1*(int64_t)sensor->dig_P5)<<17);
var2 = var2 + (((int64_t)sensor->dig_P4)<<35);
var1 = ((var1 * var1 * (int64_t)sensor->dig_P3)>>8) +
((var1 * (int64_t)sensor->dig_P2)<<12);
var1 = (((((int64_t)1)<<47)+var1))*((int64_t)sensor->dig_P1)>>33;
if (var1 == 0)
{
return 0; // avoid exception caused by division by zero
}
p = 1048576 - adc_P;
p = (((p<<31) - var2)*3125) / var1;
var1 = (((int64_t)sensor->dig_P9) * (p>>13) * (p>>13)) >> 25;
var2 = (((int64_t)sensor->dig_P8) * p) >> 19;
p = ((p + var1 + var2) >> 8) + (((int64_t)sensor->dig_P7)<<4);
return (float)p/256;
}
/*float bmp280_readAltitude(bmp280_sensor *sensor, float sealevelp)
{
float altitude;
float pressure = bmp280_readPressure(sensor); // in Si units for Pascal
pressure /= 100;
altitude = 44330 * (1.0 - pow(pressure / seaLevelhPa, 0.1903));
return altitude;
}*/
/// Helper Functions
|
