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Add functions to get/set baseline #42

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Merged
merged 2 commits into from
Apr 25, 2020
Merged

Add functions to get/set baseline #42

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3d65d3b
Add functions to get/set baseline
anlorn Apr 24, 2020
7279d2c
Add a property setter for baseline
anlorn Apr 25, 2020
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31 changes: 29 additions & 2 deletions adafruit_ccs811.py
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Original file line number Diff line number Diff line change
Expand Up @@ -44,13 +44,15 @@
__version__ = "0.0.0-auto.0"
__repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_CCS811.git"


_ALG_RESULT_DATA = const(0x02)
_RAW_DATA = const(0x03)
_ENV_DATA = const(0x05)
_NTC = const(0x06)
_THRESHOLDS = const(0x10)

# _BASELINE = 0x11
_BASELINE = const(0x11)

# _HW_ID = 0x20
# _HW_VERSION = 0x21
# _FW_BOOT_VERSION = 0x23
Expand Down Expand Up @@ -106,7 +108,6 @@ def __init__(self, i2c_bus, address=0x5A):
raise RuntimeError(
"Device ID returned is not correct! Please check your wiring."
)

# try to start the app
buf = bytearray(1)
buf[0] = 0xF4
Expand Down Expand Up @@ -156,6 +157,32 @@ def _update_data(self):
if self.error:
raise RuntimeError("Error:" + str(self.error_code))

@property
def baseline(self):
"""
The propery reads and returns the current baseline value.
The returned value is packed into an integer.
Later the same integer can be used in order
to set a new baseline.
"""
buf = bytearray(3)
buf[0] = _BASELINE
with self.i2c_device as i2c:
i2c.write_then_readinto(buf, buf, out_end=1, in_start=1)
return struct.unpack("<H", buf[1:])[0]

@baseline.setter
def baseline(self, baseline_int):
"""
The property lets you set a new baseline. As a value accepts
integer which represents packed baseline 2 bytes value.
"""
buf = bytearray(3)
buf[0] = _BASELINE
struct.pack_into("<H", buf, 1, baseline_int)
with self.i2c_device as i2c:
i2c.write(buf)

@property
def tvoc(self): # pylint: disable=invalid-name
"""Total Volatile Organic Compound in parts per billion."""
Expand Down