exec/pressure/bmp388.py

   1 #!/usr/bin/python
   2 # -*- coding: utf-8 -*-
   3 import time
   4 import smbus
   5 import math
   6
   7 # define BMP388 Device I2C address
   8
   9 I2C_ADD_BMP388_AD0_LOW = 0x76
  10 I2C_ADD_BMP388_AD0_HIGH = 0x77
  11 I2C_ADD_BMP388 = I2C_ADD_BMP388_AD0_HIGH
  12
  13 BMP388_REG_ADD_WIA = 0x00
  14 BMP388_REG_VAL_WIA = 0x50
  15
  16 BMP388_REG_ADD_ERR = 0x02
  17 BMP388_REG_VAL_FATAL_ERR = 0x01
  18 BMP388_REG_VAL_CMD_ERR = 0x02
  19 BMP388_REG_VAL_CONF_ERR = 0x04
  20
  21 BMP388_REG_ADD_STATUS = 0x03
  22 BMP388_REG_VAL_CMD_RDY = 0x10
  23 BMP388_REG_VAL_DRDY_PRESS = 0x20
  24 BMP388_REG_VAL_DRDY_TEMP = 0x40
  25
  26 BMP388_REG_ADD_CMD = 0x7E
  27 BMP388_REG_VAL_EXTMODE_EN = 0x34
  28 BMP388_REG_VAL_FIFI_FLUSH = 0xB0
  29 BMP388_REG_VAL_SOFT_RESET = 0xB6
  30
  31 BMP388_REG_ADD_PWR_CTRL = 0x1B
  32 BMP388_REG_VAL_PRESS_EN = 0x01
  33 BMP388_REG_VAL_TEMP_EN = 0x02
  34 BMP388_REG_VAL_NORMAL_MODE = 0x30
  35
  36 BMP388_REG_ADD_PRESS_XLSB = 0x04
  37 BMP388_REG_ADD_PRESS_LSB = 0x05
  38 BMP388_REG_ADD_PRESS_MSB = 0x06
  39 BMP388_REG_ADD_TEMP_XLSB = 0x07
  40 BMP388_REG_ADD_TEMP_LSB = 0x08
  41 BMP388_REG_ADD_TEMP_MSB = 0x09
  42
  43 BMP388_REG_ADD_T1_LSB = 0x31
  44 BMP388_REG_ADD_T1_MSB = 0x32
  45 BMP388_REG_ADD_T2_LSB = 0x33
  46 BMP388_REG_ADD_T2_MSB = 0x34
  47 BMP388_REG_ADD_T3 = 0x35
  48 BMP388_REG_ADD_P1_LSB = 0x36
  49 BMP388_REG_ADD_P1_MSB = 0x37
  50 BMP388_REG_ADD_P2_LSB = 0x38
  51 BMP388_REG_ADD_P2_MSB = 0x39
  52 BMP388_REG_ADD_P3 = 0x3A
  53 BMP388_REG_ADD_P4 = 0x3B
  54 BMP388_REG_ADD_P5_LSB = 0x3C
  55 BMP388_REG_ADD_P5_MSB = 0x3D
  56 BMP388_REG_ADD_P6_LSB = 0x3E
  57 BMP388_REG_ADD_P6_MSB = 0x3F
  58 BMP388_REG_ADD_P7 = 0x40
  59 BMP388_REG_ADD_P8 = 0x41
  60 BMP388_REG_ADD_P9_LSB = 0x42
  61 BMP388_REG_ADD_P9_MSB = 0x43
  62 BMP388_REG_ADD_P10 = 0x44
  63 BMP388_REG_ADD_P11 = 0x45
  64
  65
  66 class BMP388(object):
  67
  68     """docstring for BMP388"""
  69
  70     def __init__(self, address=I2C_ADD_BMP388):
  71         self._address = address
  72         self._bus = smbus.SMBus(0x01)
  73
  74         # Load calibration values.
  75
  76         if self._read_byte(BMP388_REG_ADD_WIA) == BMP388_REG_VAL_WIA:
  77             print("Pressure sersor is BMP388!\r\n")
  78             u8RegData = self._read_byte(BMP388_REG_ADD_STATUS)
  79             if u8RegData & BMP388_REG_VAL_CMD_RDY:
  80                 self._write_byte(BMP388_REG_ADD_CMD,
  81                                  BMP388_REG_VAL_SOFT_RESET)
  82                 time.sleep(0.01)
  83         else:
  84             print ("Pressure sersor NULL!\r\n")
  85         self._write_byte(BMP388_REG_ADD_PWR_CTRL,
  86                          BMP388_REG_VAL_PRESS_EN
  87                          | BMP388_REG_VAL_TEMP_EN
  88                          | BMP388_REG_VAL_NORMAL_MODE)
  89         self._load_calibration()
  90
  91     def _read_byte(self, cmd):
  92         return self._bus.read_byte_data(self._address, cmd)
  93
  94     def _read_s8(self, cmd):
  95         result = self._read_byte(cmd)
  96         if result > 128:
  97             result -= 256
  98         return result
  99
 100     def _read_u16(self, cmd):
 101         LSB = self._bus.read_byte_data(self._address, cmd)
 102         MSB = self._bus.read_byte_data(self._address, cmd + 0x01)
 103         return (MSB << 0x08) + LSB
 104
 105     def _read_s16(self, cmd):
 106         result = self._read_u16(cmd)
 107         if result > 32767:
 108             result -= 65536
 109         return result
 110
 111     def _write_byte(self, cmd, val):
 112         self._bus.write_byte_data(self._address, cmd, val)
 113
 114     def _load_calibration(self):
 115         print ("_load_calibration\r\n")
 116         self.T1 = self._read_u16(BMP388_REG_ADD_T1_LSB)
 117         self.T2 = self._read_u16(BMP388_REG_ADD_T2_LSB)
 118         self.T3 = self._read_s8(BMP388_REG_ADD_T3)
 119         self.P1 = self._read_s16(BMP388_REG_ADD_P1_LSB)
 120         self.P2 = self._read_s16(BMP388_REG_ADD_P2_LSB)
 121         self.P3 = self._read_s8(BMP388_REG_ADD_P3)
 122         self.P4 = self._read_s8(BMP388_REG_ADD_P4)
 123         self.P5 = self._read_u16(BMP388_REG_ADD_P5_LSB)
 124         self.P6 = self._read_u16(BMP388_REG_ADD_P6_LSB)
 125         self.P7 = self._read_s8(BMP388_REG_ADD_P7)
 126         self.P8 = self._read_s8(BMP388_REG_ADD_P8)
 127         self.P9 = self._read_s16(BMP388_REG_ADD_P9_LSB)
 128         self.P10 = self._read_s8(BMP388_REG_ADD_P10)
 129         self.P11 = self._read_s8(BMP388_REG_ADD_P11)
 130
 131         # print(self.T1)
 132         # print(self.T2)
 133         # print(self.T3)
 134         # print(self.P1)
 135         # print(self.P2)
 136         # print(self.P3)
 137         # print(self.P4)
 138         # print(self.P5)
 139         # print(self.P6)
 140         # print(self.P7)
 141         # print(self.P8)
 142         # print(self.P9)
 143         # print(self.P10)
 144         # print(self.P11)
 145
 146     def compensate_temperature(self, adc_T):
 147         partial_data1 = adc_T - 256 * self.T1
 148         partial_data2 = self.T2 * partial_data1
 149         partial_data3 = partial_data1 * partial_data1
 150         partial_data4 = partial_data3 * self.T3
 151         partial_data5 = partial_data2 * 262144 + partial_data4
 152         partial_data6 = partial_data5 / 4294967296
 153         self.T_fine = partial_data6
 154         comp_temp = partial_data6 * 25 / 16384
 155         return comp_temp
 156
 157     def compensate_pressure(self, adc_P):
 158         partial_data1 = self.T_fine * self.T_fine
 159         partial_data2 = partial_data1 / 0x40
 160         partial_data3 = partial_data2 * self.T_fine / 256
 161         partial_data4 = self.P8 * partial_data3 / 0x20
 162         partial_data5 = self.P7 * partial_data1 * 0x10
 163         partial_data6 = self.P6 * self.T_fine * 4194304
 164         offset = self.P5 * 140737488355328 + partial_data4 \
 165             + partial_data5 + partial_data6
 166
 167         partial_data2 = self.P4 * partial_data3 / 0x20
 168         partial_data4 = self.P3 * partial_data1 * 0x04
 169         partial_data5 = (self.P2 - 16384) * self.T_fine * 2097152
 170         sensitivity = (self.P1 - 16384) * 70368744177664 \
 171             + partial_data2 + partial_data4 + partial_data5
 172
 173         partial_data1 = sensitivity / 16777216 * adc_P
 174         partial_data2 = self.P10 * self.T_fine
 175         partial_data3 = partial_data2 + 65536 * self.P9
 176         partial_data4 = partial_data3 * adc_P / 8192
 177         partial_data5 = partial_data4 * adc_P / 512
 178         partial_data6 = adc_P * adc_P
 179         partial_data2 = self.P11 * partial_data6 / 65536
 180         partial_data3 = partial_data2 * adc_P / 128
 181         partial_data4 = offset / 0x04 + partial_data1 + partial_data5 \
 182             + partial_data3
 183         comp_press = partial_data4 * 25 / 1099511627776
 184         return comp_press
 185
 186     def get_temperature_and_pressure_and_altitude(self):
 187         """Returns pressure in Pa as double. Output value of "6386.2"equals 96386.2 Pa = 963.862 hPa."""
 188
 189         xlsb = self._read_byte(BMP388_REG_ADD_TEMP_XLSB)
 190         lsb = self._read_byte(BMP388_REG_ADD_TEMP_LSB)
 191         msb = self._read_byte(BMP388_REG_ADD_TEMP_MSB)
 192         adc_T = (msb << 0x10) + (lsb << 0x08) + xlsb
 193         temperature = self.compensate_temperature(adc_T)
 194         xlsb = self._read_byte(BMP388_REG_ADD_PRESS_XLSB)
 195         lsb = self._read_byte(BMP388_REG_ADD_PRESS_LSB)
 196         msb = self._read_byte(BMP388_REG_ADD_PRESS_MSB)
 197
 198         adc_P = (msb << 0x10) + (lsb << 0x08) + xlsb
 199         pressure = self.compensate_pressure(adc_P)
 200         altitude = 4433000 * (0x01 - pow(pressure / 100.0 / 101325.0,
 201                               0.1903))
 202
 203         return (temperature, pressure, altitude)
 204
 205
 206 if __name__ == '__main__':
 207
 208         import time
 209
 210         print("BMP388 Test Program ...\n")
 211
 212         bmp388 = BMP388()
 213
 214         while True:
 215                 time.sleep(0.5)
 216                 temperature,pressure,altitude = bmp388.get_temperature_and_pressure_and_altitude()
 217                 print(' Temperature = %.1f Pressure = %.2f  Altitude =%.2f '%(temperature/100.0,pressure/100.0,altitude/100.0))