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Ensure calibration registers loaded before read #5

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Ensure calibration registers loaded before read #5

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62dec35
Ensure calibration registers loaded before read
strongbutgood Mar 15, 2022
99c5c6e
Separate calibration data read
strongbutgood Mar 15, 2022
ffa6d30
Remove conditions from calibrate method
strongbutgood Mar 20, 2022
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40 changes: 24 additions & 16 deletions bmp280.py
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Original file line number Diff line number Diff line change
Expand Up @@ -90,22 +90,11 @@ def __init__(self, i2c_bus, addr=0x76, use_case=BMP280_CASE_HANDHELD_DYN):
self._bmp_i2c = i2c_bus
self._i2c_addr = addr

# read calibration data
# < little-endian
# H unsigned short
# h signed short
self._T1 = unp('<H', self._read(0x88, 2))[0]
self._T2 = unp('<h', self._read(0x8A, 2))[0]
self._T3 = unp('<h', self._read(0x8C, 2))[0]
self._P1 = unp('<H', self._read(0x8E, 2))[0]
self._P2 = unp('<h', self._read(0x90, 2))[0]
self._P3 = unp('<h', self._read(0x92, 2))[0]
self._P4 = unp('<h', self._read(0x94, 2))[0]
self._P5 = unp('<h', self._read(0x96, 2))[0]
self._P6 = unp('<h', self._read(0x98, 2))[0]
self._P7 = unp('<h', self._read(0x9A, 2))[0]
self._P8 = unp('<h', self._read(0x9C, 2))[0]
self._P9 = unp('<h', self._read(0x9E, 2))[0]
self._T1 = self._T2 = self._T3 = \
self._P1 = self._P2 = self._P3 = \
self._P4 = self._P5 = self._P6 = \
self._P7 = self._P8 = self._P9 = 0
self.calibrate()

# output raw
self._t_raw = 0
Expand Down Expand Up @@ -142,6 +131,25 @@ def _gauge(self):
self._t = 0
self._p = 0

def calibrate(self):
# read calibration data
# < little-endian
# H unsigned short
# h signed short
self._T1 = unp('<H', self._read(0x88, 2))[0]
self._T2 = unp('<h', self._read(0x8A, 2))[0]
self._T3 = unp('<h', self._read(0x8C, 2))[0]
self._P1 = unp('<H', self._read(0x8E, 2))[0]
self._P2 = unp('<h', self._read(0x90, 2))[0]
self._P3 = unp('<h', self._read(0x92, 2))[0]
self._P4 = unp('<h', self._read(0x94, 2))[0]
self._P5 = unp('<h', self._read(0x96, 2))[0]
self._P6 = unp('<h', self._read(0x98, 2))[0]
self._P7 = unp('<h', self._read(0x9A, 2))[0]
self._P8 = unp('<h', self._read(0x9C, 2))[0]
self._P9 = unp('<h', self._read(0x9E, 2))[0]
return self._T1 != 0

def reset(self):
self._write(_BMP280_REGISTER_RESET, 0xB6)

Expand Down