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add more retrying to make for greater stable #5

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Merged
merged 2 commits into from
Oct 2, 2018
Merged

add more retrying to make for greater stable #5

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06243aa
make I2C init more standard, move try/except into the wakeup location
ladyada Oct 2, 2018
60ef01a
add init retries
ladyada Oct 2, 2018
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17 changes: 14 additions & 3 deletions adafruit_am2320.py
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Original file line number Diff line number Diff line change
Expand Up @@ -85,12 +85,23 @@ class AM2320:

"""
def __init__(self, i2c_bus, address=AM2320_DEFAULT_ADDR):
self._i2c = I2CDevice(i2c_bus, address)
for _ in range(3):
# retry since we have to wake up the devices
try:
self._i2c = I2CDevice(i2c_bus, address)
return
except ValueError:
pass
time.sleep(0.25)
raise ValueError("AM2320 not found")

def _read_register(self, register, length):
with self._i2c as i2c:
# wake up sensor
i2c.write(bytes([0x00]))
try:
i2c.write(bytes([0x00]))
except OSError:
pass
time.sleep(0.01) # wait 10 ms

# Send command to read register
Expand All @@ -103,7 +114,7 @@ def _read_register(self, register, length):
# print("$%02X => %s" % (register, [hex(i) for i in result]))
# Check preamble indicates correct readings
if result[0] != 0x3 or result[1] != length:
raise RuntimeError('I2C modbus read failure')
raise RuntimeError('I2C read failure')
# Check CRC on all but last 2 bytes
crc1 = struct.unpack("<H", bytes(result[-2:]))[0]
crc2 = _crc16(result[0:-2])
Expand Down
15 changes: 4 additions & 11 deletions examples/am2320_simpletest.py
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Expand Up @@ -3,18 +3,11 @@
import busio
import adafruit_am2320

# can also use board.SDA and board.SCL for neater looking code!
i2c = busio.I2C(board.D2, board.D0)
# create the I2C shared bus
i2c = busio.I2C(board.SCL, board.SDA)
am = adafruit_am2320.AM2320(i2c)


while True:
try:
print("Temperature: ", am.temperature)
print("Humidity: ", am.relative_humidity)
except OSError:
# These sensors are a bit flakey, its ok if the readings fail
pass
except RuntimeError:
pass
print("Temperature: ", am.temperature)
print("Humidity: ", am.relative_humidity)
time.sleep(2)