Initial Commit

bme680/__init__.py

@@ -0,0 +1,127 @@
+from . import constants
+import math
+
+class BME680(constants.BME680):
+    def __init__(self):
+        constants.BME680.__init__(self)
+
+    def init(self):
+        pass
+
+    def soft_reset(self):
+        pass
+
+    def set_sensor_mode(self):
+        pass
+
+    def get_sensor_mode(self, mode):
+        pass
+
+    def set_profile_duration(self, duration):
+        pass
+
+    def get_profile_duration(self):
+        pass
+
+    def _get_sensor_data(self):
+        pass
+
+    def _get_regs(self, addr, length):
+        pass
+
+    def _get_calibration_data(self):
+        calibration = self._get_regs(constants.COEFF_ADDR1, constants.COEFF_ADDR1_LEN)
+        calibration += self._get_regs(constants.COEFF_ADDR2, constants.COEFF_ADDR2_LEN)
+
+        heat_range = self._get_regs(constants.ADDR_RES_HEAT_RANGE_ADDR, 1)[0]
+        heat_value = self._get_regs(constants.ADDR_RES_HEAT_VAL_ADDR, 1)[0]
+        sw_error = self._get_regs(constants.ADDR_RANGE_SW_ERR_ADDR, 1)[0]
+
+        self.calibration_data.set_from_array(calibration)
+        self.calibration_data.set_other(heat_range, heat_value, sw_error)
+        
+    def _calc_temperature(self, temperature_adc):
+        var1 = (temperature_adc / 8) - (self.calibration_data.par_t1 * 2)
+        var2 = (var1 * self.calibration_data.par_t2) / 2048
+        var3 = ((var1 / 2) * (var1 / 2)) / 4096
+        var3 = ((var3) * (self.calibration_data.par_t3 * 16)) / 16384
+
+        # Save teperature data for pressure calculations
+        self.calibration_data.t_fine = (var2 + var3)
+        calc_temp = (((self.calibration_data.t_fine * 5) + 128) / 256)
+
+        return calc_temp
+
+    def _calc_pressure(self, pressure_adc):
+        var1 = (self.calibration_data.t_fine / 2) - 64000
+        var2 = ((var1 / 4) * (var1 / 4)) / 2048
+        var2 = (var2 * self.calibration_data.par_p6) / 4
+        var2 = var2 + ((var1 * self.calibration_data.par_p5) * 2)
+        var2 = (var2 / 4) + (self.calibration_data.par_p4 * 65536)
+        
+        var1 = ((var1 / 4) * (var1 / 4)) / 8192
+        var1 = ((var1 * (self.calibration_data.par_p3 * 32)) / 8) + ((self.calibration_data.par_p2 * var1) / 2)
+        var1 = var1 / 262144
+        var1 = ((32768 + var1) * self.calibration_data.par_p1) / 32768
+        calc_pres = 1048576 - pressure_adc
+        calc_pres = (calc_pres - (var2 / 4096)) * 3125
+        calc_pres = (calc_pres / var1) * 2
+        var1 = (self.calibration_data.par_p9 * (((calc_pres / 8) * (calc_pres / 8)) / 8192)) / 4096
+        var2 = ((calc_pres / 4) * self.calibration_data.par_p8) / 8192
+        var3 = ((calc_pres / 256)
+                * (calc_pres / 256)
+                * (calc_pres / 256)
+                * self.calibration_data.par_p10) / 131072
+        calc_pres = calc_pres + ((var1 + var2 + var3 + (self.calibration_data.par_p7 * 128)) / 16)
+
+        return calc_pres
+
+    def _calc_humidity(self, humidity_adc):
+        temp_scaled = ((self.calibration_data.t_fine * 5) + 128) / 256
+        var1 = (humidity_adc - ((self.calibration_data.par_h1 * 16))) \
+                - (((temp_scaled * self.calibration_data.par_h3) / (100)) / 2)
+        var2 = (self.calibration_data.par_h2
+                * (((temp_scaled * self.calibration_data.par_h4) / (100))
+                + (((temp_scaled * ((temp_scaled * self.calibration_data.par_h5) / (100))) / 64)
+                / (100)) + (1 * 16384))) / 1024
+        var3 = var1 * var2
+        var4 = self.calibration_data.par_h6 * 128
+        var4 = ((var4) + ((temp_scaled * self.calibration_data.par_h7) / (100))) / 16
+        var5 = ((var3 / 16384) * (var3 / 16384)) / 1024
+        var6 = (var4 * var5) / 2
+        calc_hum = (((var3 + var6) / 1024) * (1000)) / 4096
+
+        return min(max(calc_hum,0),100000)
+
+    def _calc_gas_resistance(self, gas_res_adc, gas_range):
+        var1 = ((1340 + (5 * self.calibration_data.range_sw_err)) * (constants.lookupTable1[gas_range])) / 65536
+        var2 = (((gas_res_adc * 32768) - (16777216)) + var1)
+        var3 = ((constants.lookupTable2[gas_range] * var1) / 512)
+        calc_gas_res = ((var3 + (var2 / 2)) / var2)
+
+        return calc_gas_res
+
+    def _calc_heater_resistance(self, temperature):
+        temperature = min(max(temperature,200),400)
+
+        var1 = ((self.ambient_temperature * self.calibration_data.par_gh3) / 1000) * 256
+        var2 = (self.calibration_data.par_gh1 + 784) * (((((self.calibration_data.par_gh2 + 154009) * temperature * 5) / 100) + 3276800) / 10)
+        var3 = var1 + (var2 / 2)
+        var4 = (var3 / (self.calibration_data.res_heat_range + 4))
+        var5 = (131 * self.calibration_data.res_heat_val) + 65536
+        heatr_res_x100 = (((var4 / var5) - 250) * 34)
+        heatr_res = ((heatr_res_x100 + 50) / 100)
+
+        return int(heatr_res)
+
+    def _calc_heater_duration(self, duration):
+        if duration < 0xfc0:
+            factor = 0
+
+            while duration > 0x3f:
+                duration /= 4
+                factor += 1
+
+            return int(duration + (factor * 64))
+
+        return 0xff

bme680/constants.py

@@ -0,0 +1,381 @@
+# BME680 General config
+POLL_PERIOD_MS = 10
+
+# BME680 I2C addresses
+I2C_ADDR_PRIMARY = 0x76
+I2C_ADDR_SECONDARY = 0x77
+
+# BME680 unique chip identifier
+CHIP_ID = 0x61
+
+# BME680 coefficients related defines
+COEFF_SIZE = 41
+COEFF_ADDR1_LEN = 25
+COEFF_ADDR2_LEN = 16
+
+# BME680 field_x related defines
+FIELD_LENGTH = 15
+FIELD_ADDR_OFFSET = 17
+
+# Soft reset command
+SOFT_RESET_CMD = 0xb6
+
+# Error code definitions
+OK = 0
+# Errors
+E_NULL_PTR = -1
+E_COM_FAIL = -2
+E_DEV_NOT_FOUND = -3
+E_INVALID_LENGTH = -4
+
+# Warnings
+W_DEFINE_PWR_MODE = 1
+W_NO_NEW_DATA = 2
+
+# Info's
+I_MIN_CORRECTION = 1
+I_MAX_CORRECTION = 2
+
+# Register map
+# Other coefficient's address
+ADDR_RES_HEAT_VAL_ADDR = 0x00
+ADDR_RES_HEAT_RANGE_ADDR = 0x02
+ADDR_RANGE_SW_ERR_ADDR = 0x04
+ADDR_SENS_CONF_START = 0x5A
+ADDR_GAS_CONF_START = 0x64
+
+# Field settings
+FIELD0_ADDR = 0x1d
+
+# Heater settings
+RES_HEAT0_ADDR = 0x5a
+GAS_WAIT0_ADDR = 0x64
+
+# Sensor configuration registers
+CONF_HEAT_CTRL_ADDR = 0x70
+CONF_ODR_RUN_GAS_NBC_ADDR = 0x71
+CONF_OS_H_ADDR = 0x72
+MEM_PAGE_ADDR = 0xf3
+CONF_T_P_MODE_ADDR = 0x74
+CONF_ODR_FILT_ADDR = 0x75
+
+# Coefficient's address
+COEFF_ADDR1 = 0x89
+COEFF_ADDR2 = 0xe1
+
+# Chip identifier
+CHIP_ID_ADDR = 0xd0
+
+# Soft reset register
+SOFT_RESET_ADDR = 0xe0
+
+# Heater control settings
+ENABLE_HEATER = 0x00
+DISABLE_HEATER = 0x08
+
+# Gas measurement settings
+DISABLE_GAS_MEAS = 0x00
+ENABLE_GAS_MEAS = 0x01
+
+# Over-sampling settings
+OS_NONE = 0
+OS_1X = 1
+OS_2X = 2
+OS_4X = 3
+OS_8X = 4
+OS_16X = 5
+
+# IIR filter settings
+FILTER_SIZE_0 = 0
+FILTER_SIZE_1 = 1
+FILTER_SIZE_3 = 2
+FILTER_SIZE_7 = 3
+FILTER_SIZE_15 = 4
+FILTER_SIZE_31 = 5
+FILTER_SIZE_63 = 6
+FILTER_SIZE_127 = 7
+
+# Power mode settings
+SLEEP_MODE = 0
+FORCED_MODE = 1
+
+# Delay related macro declaration
+RESET_PERIOD = 10
+
+# SPI memory page settings
+MEM_PAGE0 = 0x10
+MEM_PAGE1 = 0x00
+
+# Ambient humidity shift value for compensation
+HUM_REG_SHIFT_VAL = 4
+
+# Run gas enable and disable settings
+RUN_GAS_DISABLE = 0
+RUN_GAS_ENABLE = 1
+
+# Buffer length macro declaration
+TMP_BUFFER_LENGTH = 40
+REG_BUFFER_LENGTH = 6
+FIELD_DATA_LENGTH = 3
+GAS_REG_BUF_LENGTH = 20
+GAS_HEATER_PROF_LEN_MAX  = 10
+
+# Settings selector
+OST_SEL = 1
+OSP_SEL = 2
+OSH_SEL = 4
+GAS_MEAS_SEL = 8
+FILTER_SEL = 16
+HCNTRL_SEL = 32
+RUN_GAS_SEL = 64
+NBCONV_SEL = 128
+GAS_SENSOR_SEL = GAS_MEAS_SEL | RUN_GAS_SEL | NBCONV_SEL
+
+# Number of conversion settings
+NBCONV_MIN = 0
+NBCONV_MAX = 10
+
+# Mask definitions
+GAS_MEAS_MSK = 0x30
+NBCONV_MSK = 0X0F
+FILTER_MSK = 0X1C
+OST_MSK = 0XE0
+OSP_MSK = 0X1C
+OSH_MSK = 0X07
+HCTRL_MSK = 0x08
+RUN_GAS_MSK = 0x10
+MODE_MSK = 0x03
+RHRANGE_MSK = 0x30
+RSERROR_MSK = 0xf0
+NEW_DATA_MSK = 0x80
+GAS_INDEX_MSK = 0x0f
+GAS_RANGE_MSK = 0x0f
+GASM_VALID_MSK = 0x20
+HEAT_STAB_MSK = 0x10
+MEM_PAGE_MSK = 0x10
+SPI_RD_MSK = 0x80
+SPI_WR_MSK = 0x7f
+BIT_H1_DATA_MSK = 0x0F
+
+# Bit position definitions for sensor settings
+GAS_MEAS_POS = 4
+FILTER_POS = 2
+OST_POS = 5
+OSP_POS = 2
+RUN_GAS_POS = 4
+
+# Array Index to Field data mapping for Calibration Data
+T2_LSB_REG = 1
+T2_MSB_REG = 2
+T3_REG = 3
+P1_LSB_REG = 5
+P1_MSB_REG = 6
+P2_LSB_REG = 7
+P2_MSB_REG = 8
+P3_REG = 9
+P4_LSB_REG = 11
+P4_MSB_REG = 12
+P5_LSB_REG = 13
+P5_MSB_REG = 14
+P7_REG = 15
+P6_REG = 16
+P8_LSB_REG = 19
+P8_MSB_REG = 20
+P9_LSB_REG = 21
+P9_MSB_REG = 22
+P10_REG = 23
+H2_MSB_REG = 25
+H2_LSB_REG = 26
+H1_LSB_REG = 26
+H1_MSB_REG = 27
+H3_REG = 28
+H4_REG = 29
+H5_REG = 30
+H6_REG = 31
+H7_REG = 32
+T1_LSB_REG = 33
+T1_MSB_REG = 34
+GH2_LSB_REG = 35
+GH2_MSB_REG = 36
+GH1_REG = 37
+GH3_REG = 38
+
+# BME680 register buffer index settings
+REG_FILTER_INDEX = 5
+REG_TEMP_INDEX = 4
+REG_PRES_INDEX = 4
+REG_HUM_INDEX = 2
+REG_NBCONV_INDEX = 1
+REG_RUN_GAS_INDEX = 1
+REG_HCTRL_INDEX = 0
+
+# Look up tables for the possible gas range values
+lookupTable1 = [2147483647, 2147483647, 2147483647, 2147483647,
+        2147483647, 2126008810, 2147483647, 2130303777, 2147483647,
+        2147483647, 2143188679, 2136746228, 2147483647, 2126008810,
+        2147483647, 2147483647]
+
+lookupTable2 = [4096000000, 2048000000, 1024000000, 512000000,
+        255744255, 127110228, 64000000, 32258064,
+        16016016, 8000000, 4000000, 2000000,
+        1000000, 500000, 250000, 125000]
+
+def bytes_to_word(msb, lsb):
+    return (msb << 8) | lsb
+
+# Sensor field data structure
+
+class FieldData:
+    def __init__(self):
+        # Contains new_data, gasm_valid & heat_stab
+        self.status = None
+        # The index of the heater profile used
+        self.gas_index = None
+        # Measurement index to track order
+        self.meas_index = None
+        # Temperature in degree celsius x100
+        self.temperature = None
+        # Pressure in Pascal
+        self.pressure = None
+        # Humidity in % relative humidity x1000
+        self.humidity = None
+        # Gas resistance in Ohms
+        self.gas_resistance = None
+
+# Structure to hold the Calibration data
+
+class CalibrationData:
+    def __init__(self):
+        self.par_h1 = None
+        self.par_h2 = None
+        self.par_h3 = None
+        self.par_h4 = None
+        self.par_h5 = None
+        self.par_h6 = None
+        self.par_h7 = None
+        self.par_gh1 = None
+        self.par_gh2 = None
+        self.par_gh3 = None
+        self.par_t1 = None
+        self.par_t2 = None
+        self.par_t3 = None
+        self.par_p1 = None
+        self.par_p2 = None
+        self.par_p3 = None
+        self.par_p4 = None
+        self.par_p5 = None
+        self.par_p6 = None
+        self.par_p7 = None
+        self.par_p8 = None
+        self.par_p9 = None
+        self.par_p10 = None
+        # Variable to store t_fine size
+        self.t_fine = None
+        # Variable to store heater resistance range
+        self.res_heat_range = None
+        # Variable to store heater resistance value
+        self.res_heat_val = None
+        # Variable to store error range
+        self.range_sw_err = None
+
+    def set_from_array(self, calibration):
+        # Temperature related coefficients
+        self.par_t1 = bytes_to_word(calibration[T1_MSB_REG], calibration[T1_LSB_REG])
+        self.par_t2 = bytes_to_word(calibration[T2_MSB_REG], calibration[T2_LSB_REG])
+        self.par_t3 = calibration[T3_REG]
+
+        # Pressure related coefficients
+        self.par_p1 = bytes_to_word(calibration[P1_MSB_REG], calibration[P1_LSB_REG])
+        self.par_p2 = bytes_to_word(calibration[P2_MSB_REG], calibration[P2_LSB_REG])
+        self.par_p3 = calibration[P3_REG]
+        self.par_p4 = bytes_to_word(calibration[P4_MSB_REG], calibration[P4_LSB_REG])
+        self.par_p5 = bytes_to_word(calibration[P5_MSB_REG], calibration[P5_LSB_REG])
+        self.par_p6 = calibration[P6_REG]
+        self.par_p7 = calibration[P7_REG]
+        self.par_p8 = bytes_to_word(calibration[P8_MSB_REG], calibration[P8_LSB_REG])
+        self.par_p9 = bytes_to_word(calibration[P9_MSB_REG], calibration[P9_LSB_REG])
+        self.par_p10 = calibration[P10_REG]
+
+        # Humidity related coefficients
+        self.par_h1 = (calibration[H1_MSB_REG] << HUM_REG_SHIFT_VAL) | (calibration[H1_LSB_REG] & BIT_H1_DATA_MSK)
+        self.par_h2 = (calibration[H2_MSB_REG] << HUM_REG_SHIFT_VAL) | (calibration[H2_LSB_REG] >> HUM_REG_SHIFT_VAL)
+        self.par_h3 = calibration[H3_REG]
+        self.par_h4 = calibration[H4_REG]
+        self.par_h5 = calibration[H5_REG]
+        self.par_h6 = calibration[H6_REG]
+        self.par_h7 = calibration[H7_REG]
+
+        # Gas heater related coefficients
+        self.par_gh1 = calibration[GH1_REG]
+        self.par_gh2 = bytes_to_word(calibration[GH2_MSB_REG], calibration[GH2_LSB_REG])
+        self.par_gh3 = calibration[GH3_REG]
+
+    def set_other(self, heat_range, heat_value, sw_error):
+        self.res_heat_range = (heat_range & RHRANGE_MSK) / 16
+        self.res_heat_val = heat_value
+        self.range_sw_err = (sw_error * RSERROR_MSK) / 16
+
+# BME680 sensor settings structure which comprises of ODR,
+# over-sampling and filter settings.
+
+class TPHSettings:
+    def __init__(self):
+        # Humidity oversampling
+        self.os_hum = None
+        # Temperature oversampling
+        self.os_temp = None
+        # Pressure oversampling
+        self.os_pres = None
+        # Filter coefficient
+        self.filter = None
+
+# BME680 gas sensor which comprises of gas settings
+## and status parameters
+
+class GasSettings:
+    def __init__(self):
+        # Variable to store nb conversion
+        self.nb_conv = None
+        # Variable to store heater control
+        self.heatr_ctrl = None
+        # Run gas enable value
+        self.run_gas = None
+        # Pointer to store heater temperature
+        self.heatr_temp = None
+        # Pointer to store duration profile
+        self.heatr_dur = None
+
+# BME680 device structure
+
+class BME680:
+    def __init__(self):
+        # Chip Id
+        self.chip_id = None
+        # Device Id
+        self.dev_id = None
+        # SPI/I2C interface
+        self.intf = None
+        # Memory page used
+        self.mem_page = None
+        # Ambient temperature in Degree C
+        self.ambient_temperature = None
+        # Sensor calibration data
+        self.calibration_data = CalibrationData()
+        # Sensor settings
+        self.tph_settings = TPHSettings()
+        # Gas Sensor settings
+        self.gas_settings = GasSettings()
+        # Sensor power modes
+        self.power_mode = None
+        # New sensor fields
+        self.new_fields = None
+        # Store the info messages
+        self.info_msg = None
+        # Burst read structure
+        self.read = None
+        # Burst write structure
+        self.write = None
+        # Delay in ms
+        self.delay_ms = None
+        # Communication function result
+        self.com_rslt = None