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Fix temperature reads and RP2040 reset quirk #22

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Merged
merged 2 commits into from
Jul 27, 2022
Merged

Fix temperature reads and RP2040 reset quirk #22

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7044454
some fixes
caternuson Jul 27, 2022
830cb3b
add exception type
caternuson Jul 27, 2022
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19 changes: 14 additions & 5 deletions adafruit_mpl3115a2.py
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Original file line number Diff line number Diff line change
Expand Up @@ -141,7 +141,11 @@ def __init__(self, i2c, *, address=_MPL3115A2_ADDRESS):
pass
time.sleep(0.01)
# Poll for the reset to finish.
self._poll_reg1(_MPL3115A2_CTRL_REG1_RST)
# try/except is a hack for RP2040
try:
self._poll_reg1(_MPL3115A2_CTRL_REG1_RST)
except OSError:
self._poll_reg1(_MPL3115A2_CTRL_REG1_RST)
# Configure the chip registers with default values.
self._ctrl_reg1 = _MPL3115A2_CTRL_REG1_OS128 | _MPL3115A2_CTRL_REG1_ALT
self._write_u8(_MPL3115A2_CTRL_REG1, self._ctrl_reg1)
Expand Down Expand Up @@ -198,7 +202,7 @@ def pressure(self):
self._write_u8(_MPL3115A2_CTRL_REG1, self._ctrl_reg1)
self._ctrl_reg1 |= 0b00000010 # Set OST to 1 to start measurement.
self._write_u8(_MPL3115A2_CTRL_REG1, self._ctrl_reg1)
# Poll status for PDR to be set.
# Poll status for PDR to be set = press conversion complete
while (
self._read_u8(_MPL3115A2_REGISTER_STATUS) & _MPL3115A2_REGISTER_STATUS_PDR
== 0
Expand All @@ -211,8 +215,8 @@ def pressure(self):
(self._BUFFER[0] << 16) | (self._BUFFER[1] << 8) | self._BUFFER[2]
) & 0xFFFFFF
pressure >>= 4
# Scale down to pascals.
return pressure / 4.0
# Scale down to hectopascals.
return pressure / 400.0

@property
def altitude(self):
Expand Down Expand Up @@ -248,7 +252,12 @@ def altitude(self):
@property
def temperature(self):
"""Read the temperature as measured by the sensor in degrees Celsius."""
# Poll status for TDR to be set.
# First poll for a measurement to be finished.
self._poll_reg1(_MPL3115A2_CTRL_REG1_OST)
# Initatiate a one-shot measurement
self._ctrl_reg1 |= 0b00000010 # Set OST to 1 to start measurement.
self._write_u8(_MPL3115A2_CTRL_REG1, self._ctrl_reg1)
# Poll status for TDR to be set = temp conv complete
while (
self._read_u8(_MPL3115A2_REGISTER_STATUS) & _MPL3115A2_REGISTER_STATUS_TDR
== 0
Expand Down