jepler/Adafruit_CircuitPython_AMG88xx
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Merge pull request #16 from peterhinch/temperature_fixes

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Fixes for temperature conversion bugs issue #15.
This commit is contained in:
Limor "Ladyada" Fried 2019-05-22 14:15:17 -04:00 committed by GitHub
commit 9f7a86830c
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GPG key ID: 4AEE18F83AFDEB23
1 changed files with 9 additions and 3 deletions
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12
adafruit_amg88xx.py
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@ -54,7 +54,7 @@ from micropython import const
# Operating Modes
# pylint: disable=bad-whitespace
_NORMAL_MODE = const(0x00)
_SLEEP_MODE = const(0x01)
_SLEEP_MODE = const(0x10)
_STAND_BY_60 = const(0x20)
_STAND_BY_10 = const(0x21)
@ -86,10 +86,16 @@ _THERMISTOR_CONVERSION = .0625
def _signed_12bit_to_float(val):
#take first 11 bits as absolute val
abs_val = (val & 0x7FF)
if val & 0x8000:
if val & 0x800:
return 0 - float(abs_val)
return float(abs_val)
def _twos_comp_to_float(val):
val &= 0xfff
if val & 0x800:
val -= 0x1000
return float(val)
class AMG88XX:
"""Driver for the AMG88xx GRID-Eye IR 8x8 thermal camera."""
@ -161,6 +167,6 @@ class AMG88XX:
i2c.readinto(buf, start=1)
raw = (buf[2] << 8) | buf[1]
retbuf[row][col] = _signed_12bit_to_float(raw) * _PIXEL_TEMP_CONVERSION
retbuf[row][col] = _twos_comp_to_float(raw) * _PIXEL_TEMP_CONVERSION
return retbuf