From bcac66e038e81879006b78ad71c10599850daed8 Mon Sep 17 00:00:00 2001
From: Blaise Thompson <blaise@untzag.com>
Date: Wed, 30 Jun 2021 16:43:00 -0500
Subject: return bme680

---
 firmware/bme680.py | 229 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 229 insertions(+)
 create mode 100644 firmware/bme680.py

diff --git a/firmware/bme680.py b/firmware/bme680.py
new file mode 100644
index 0000000..802bd80
--- /dev/null
+++ b/firmware/bme680.py
@@ -0,0 +1,229 @@
+# Spaces, comments and some functions have been removed from the original file to save memory
+# Original source: https://github.com/adafruit/Adafruit_CircuitPython_BME680/blob/master/adafruit_bme680.py
+import time
+import math
+from micropython import const
+from ubinascii import hexlify as hex
+try:
+  import struct
+except ImportError:
+  import ustruct as struct
+_BME680_CHIPID = const(0x61)
+_BME680_REG_CHIPID = const(0xD0)
+_BME680_BME680_COEFF_ADDR1 = const(0x89)
+_BME680_BME680_COEFF_ADDR2 = const(0xE1)
+_BME680_BME680_RES_HEAT_0 = const(0x5A)
+_BME680_BME680_GAS_WAIT_0 = const(0x64)
+_BME680_REG_SOFTRESET = const(0xE0)
+_BME680_REG_CTRL_GAS = const(0x71)
+_BME680_REG_CTRL_HUM = const(0x72)
+_BME280_REG_STATUS = const(0xF3)
+_BME680_REG_CTRL_MEAS = const(0x74)
+_BME680_REG_CONFIG = const(0x75)
+_BME680_REG_PAGE_SELECT = const(0x73)
+_BME680_REG_MEAS_STATUS = const(0x1D)
+_BME680_REG_PDATA = const(0x1F)
+_BME680_REG_TDATA = const(0x22)
+_BME680_REG_HDATA = const(0x25)
+_BME680_SAMPLERATES = (0, 1, 2, 4, 8, 16)
+_BME680_FILTERSIZES = (0, 1, 3, 7, 15, 31, 63, 127)
+_BME680_RUNGAS = const(0x10)
+_LOOKUP_TABLE_1 = (2147483647.0, 2147483647.0, 2147483647.0, 2147483647.0, 2147483647.0,
+  2126008810.0, 2147483647.0, 2130303777.0, 2147483647.0, 2147483647.0,
+  2143188679.0, 2136746228.0, 2147483647.0, 2126008810.0, 2147483647.0,
+  2147483647.0)
+_LOOKUP_TABLE_2 = (4096000000.0, 2048000000.0, 1024000000.0, 512000000.0, 255744255.0, 127110228.0,
+  64000000.0, 32258064.0, 16016016.0, 8000000.0, 4000000.0, 2000000.0, 1000000.0,
+  500000.0, 250000.0, 125000.0)
+def _read24(arr):
+  ret = 0.0
+  for b in arr:
+    ret *= 256.0
+    ret += float(b & 0xFF)
+  return ret
+class Adafruit_BME680:
+  def __init__(self, *, refresh_rate=10):
+    self._write(_BME680_REG_SOFTRESET, [0xB6])
+    time.sleep(0.005)
+    chip_id = self._read_byte(_BME680_REG_CHIPID)
+    if chip_id != _BME680_CHIPID:
+      raise RuntimeError('Failed 0x%x' % chip_id)
+    self._read_calibration()
+    self._write(_BME680_BME680_RES_HEAT_0, [0x73])
+    self._write(_BME680_BME680_GAS_WAIT_0, [0x65])
+    self.sea_level_pressure = 1013.25
+    self._pressure_oversample = 0b011
+    self._temp_oversample = 0b100
+    self._humidity_oversample = 0b010
+    self._filter = 0b010
+    self._adc_pres = None
+    self._adc_temp = None
+    self._adc_hum = None
+    self._adc_gas = None
+    self._gas_range = None
+    self._t_fine = None
+    self._last_reading = 0
+    self._min_refresh_time = 1000 / refresh_rate
+  @property
+  def pressure_oversample(self):
+    return _BME680_SAMPLERATES[self._pressure_oversample]
+  @pressure_oversample.setter
+  def pressure_oversample(self, sample_rate):
+    if sample_rate in _BME680_SAMPLERATES:
+      self._pressure_oversample = _BME680_SAMPLERATES.index(sample_rate)
+    else:
+      raise RuntimeError("Invalid")
+  @property
+  def humidity_oversample(self):
+    return _BME680_SAMPLERATES[self._humidity_oversample]
+  @humidity_oversample.setter
+  def humidity_oversample(self, sample_rate):
+    if sample_rate in _BME680_SAMPLERATES:
+      self._humidity_oversample = _BME680_SAMPLERATES.index(sample_rate)
+    else:
+      raise RuntimeError("Invalid")
+  @property
+  def temperature_oversample(self):
+      return _BME680_SAMPLERATES[self._temp_oversample]
+  @temperature_oversample.setter
+  def temperature_oversample(self, sample_rate):
+    if sample_rate in _BME680_SAMPLERATES:
+      self._temp_oversample = _BME680_SAMPLERATES.index(sample_rate)
+    else:
+      raise RuntimeError("Invalid")
+  @property
+  def filter_size(self):
+    return _BME680_FILTERSIZES[self._filter]
+  @filter_size.setter
+  def filter_size(self, size):
+    if size in _BME680_FILTERSIZES:
+      self._filter = _BME680_FILTERSIZES[size]
+    else:
+      raise RuntimeError("Invalid")
+  @property
+  def temperature(self):
+    self._perform_reading()
+    calc_temp = (((self._t_fine * 5) + 128) / 256)
+    return calc_temp / 100
+  @property
+  def pressure(self):
+    self._perform_reading()
+    var1 = (self._t_fine / 2) - 64000
+    var2 = ((var1 / 4) * (var1 / 4)) / 2048
+    var2 = (var2 * self._pressure_calibration[5]) / 4
+    var2 = var2 + (var1 * self._pressure_calibration[4] * 2)
+    var2 = (var2 / 4) + (self._pressure_calibration[3] * 65536)
+    var1 = (((((var1 / 4) * (var1 / 4)) / 8192) *
+      (self._pressure_calibration[2] * 32) / 8) +
+      ((self._pressure_calibration[1] * var1) / 2))
+    var1 = var1 / 262144
+    var1 = ((32768 + var1) * self._pressure_calibration[0]) / 32768
+    calc_pres = 1048576 - self._adc_pres
+    calc_pres = (calc_pres - (var2 / 4096)) * 3125
+    calc_pres = (calc_pres / var1) * 2
+    var1 = (self._pressure_calibration[8] * (((calc_pres / 8) * (calc_pres / 8)) / 8192)) / 4096
+    var2 = ((calc_pres / 4) * self._pressure_calibration[7]) / 8192
+    var3 = (((calc_pres / 256) ** 3) * self._pressure_calibration[9]) / 131072
+    calc_pres += ((var1 + var2 + var3 + (self._pressure_calibration[6] * 128)) / 16)
+    return calc_pres  # Pa
+  @property
+  def humidity(self):
+    self._perform_reading()
+    temp_scaled = ((self._t_fine * 5) + 128) / 256
+    var1 = ((self._adc_hum - (self._humidity_calibration[0] * 16)) -
+      ((temp_scaled * self._humidity_calibration[2]) / 200))
+    var2 = (self._humidity_calibration[1] *
+      (((temp_scaled * self._humidity_calibration[3]) / 100) +
+       (((temp_scaled * ((temp_scaled * self._humidity_calibration[4]) / 100)) /
+         64) / 100) + 16384)) / 1024
+    var3 = var1 * var2
+    var4 = self._humidity_calibration[5] * 128
+    var4 = (var4 + ((temp_scaled * self._humidity_calibration[6]) / 100)) / 16
+    var5 = ((var3 / 16384) * (var3 / 16384)) / 1024
+    var6 = (var4 * var5) / 2
+    calc_hum = (((var3 + var6) / 1024) * 1000) / 4096
+    calc_hum /= 1000
+    if calc_hum > 100:
+      calc_hum = 100
+    if calc_hum < 0:
+      calc_hum = 0
+    return calc_hum
+  @property
+  def altitude(self):
+    pressure = self.pressure
+    return 44330 * (1.0 - math.pow(pressure / self.sea_level_pressure, 0.1903))
+  @property
+  def gas(self):
+    self._perform_reading()
+    var1 = ((1340 + (5 * self._sw_err)) * (_LOOKUP_TABLE_1[self._gas_range])) / 65536
+    var2 = ((self._adc_gas * 32768) - 16777216) + var1
+    var3 = (_LOOKUP_TABLE_2[self._gas_range] * var1) / 512
+    calc_gas_res = (var3 + (var2 / 2)) / var2
+    return int(calc_gas_res)
+  def _perform_reading(self):
+    if (time.ticks_diff(self._last_reading, time.ticks_ms()) * time.ticks_diff(0, 1)
+        < self._min_refresh_time):
+      return
+    self._write(_BME680_REG_CONFIG, [self._filter << 2])
+    self._write(_BME680_REG_CTRL_MEAS,
+      [(self._temp_oversample << 5)|(self._pressure_oversample << 2)])
+    self._write(_BME680_REG_CTRL_HUM, [self._humidity_oversample])
+    self._write(_BME680_REG_CTRL_GAS, [_BME680_RUNGAS])
+    ctrl = self._read_byte(_BME680_REG_CTRL_MEAS)
+    ctrl = (ctrl & 0xFC) | 0x01
+    self._write(_BME680_REG_CTRL_MEAS, [ctrl])
+    new_data = False
+    while not new_data:
+      data = self._read(_BME680_REG_MEAS_STATUS, 15)
+      new_data = data[0] & 0x80 != 0
+      time.sleep(0.005)
+    self._last_reading = time.ticks_ms()
+    self._adc_pres = _read24(data[2:5]) / 16
+    self._adc_temp = _read24(data[5:8]) / 16
+    self._adc_hum = struct.unpack('>H', bytes(data[8:10]))[0]
+    self._adc_gas = int(struct.unpack('>H', bytes(data[13:15]))[0] / 64)
+    self._gas_range = data[14] & 0x0F
+    var1 = (self._adc_temp / 8) - (self._temp_calibration[0] * 2)
+    var2 = (var1 * self._temp_calibration[1]) / 2048
+    var3 = ((var1 / 2) * (var1 / 2)) / 4096
+    var3 = (var3 * self._temp_calibration[2] * 16) / 16384
+    self._t_fine = int(var2 + var3)
+  def _read_calibration(self):
+    coeff = self._read(_BME680_BME680_COEFF_ADDR1, 25)
+    coeff += self._read(_BME680_BME680_COEFF_ADDR2, 16)
+    coeff = list(struct.unpack('<hbBHhbBhhbbHhhBBBHbbbBbHhbb', bytes(coeff[1:39])))
+    coeff = [float(i) for i in coeff]
+    self._temp_calibration = [coeff[x] for x in [23, 0, 1]]
+    self._pressure_calibration = [coeff[x] for x in [3, 4, 5, 7, 8, 10, 9, 12, 13, 14]]
+    self._humidity_calibration = [coeff[x] for x in [17, 16, 18, 19, 20, 21, 22]]
+    self._gas_calibration = [coeff[x] for x in [25, 24, 26]]
+    self._humidity_calibration[1] *= 16
+    self._humidity_calibration[1] += self._humidity_calibration[0] % 16
+    self._humidity_calibration[0] /= 16
+    self._heat_range = (self._read_byte(0x02) & 0x30) / 16
+    self._heat_val = self._read_byte(0x00)
+    self._sw_err = (self._read_byte(0x04) & 0xF0) / 16
+  def _read_byte(self, register):
+    return self._read(register, 1)[0]
+  def _read(self, register, length):
+    raise NotImplementedError()
+  def _write(self, register, values):
+    raise NotImplementedError()
+class BME680(Adafruit_BME680):
+  def __init__(self, i2c, address=0x77, debug=False, *, refresh_rate=10):
+    self._i2c = i2c
+    self._address = address
+    self._debug = debug
+    super().__init__(refresh_rate=refresh_rate)
+  def _read(self, register, length):
+    result = bytearray(length)
+    self._i2c.readfrom_mem_into(self._address, register & 0xff, result)
+    if self._debug:
+      print("\t${:x} read ".format(register), " ".join(["{:02x}".format(i) for i in result]))
+    return result
+  def _write(self, register, values):
+    if self._debug:
+      print("\t${:x} write".format(register), " ".join(["{:02x}".format(i) for i in values]))
+    for value in values:
+      self._i2c.writeto_mem(self._address, register, bytearray([value & 0xFF]))
+      register += 1
-- 
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