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Attempt to increase reliability for UART #6

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Merged
merged 1 commit into from
Aug 10, 2020
Merged

Attempt to increase reliability for UART #6

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16 changes: 8 additions & 8 deletions adafruit_pm25.py
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Original file line number Diff line number Diff line change
Expand Up @@ -172,17 +172,17 @@ def __init__(self, uart, reset_pin=None):
super().__init__()

def _read_into_buffer(self):
b = self._uart.read(1)
if not b:
raise RuntimeError("Unable to read from PM2.5 UART")
b = b[0]
if b != 0x42:
raise RuntimeError("Unable to read from PM2.5 UART")
self._buffer[0] = b # read one byte
while True:
b = self._uart.read(1)
if not b:
raise RuntimeError("Unable to read from PM2.5 (no start of frame)")
if b[0] == 0x42:
break
self._buffer[0] = b[0] # first byte and start of frame

remain = self._uart.read(31)
if not remain or len(remain) != 31:
raise RuntimeError("Unable to read from PM2.5 UART")
raise RuntimeError("Unable to read from PM2.5 (incomplete frame)")
for i in range(31):
self._buffer[i + 1] = remain[i]
# print([hex(i) for i in self._buffer])