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PN532_SPI._wait_ready: fixed command overwriting #29

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Merged
jepler merged 1 commit into from
Jan 7, 2020
Merged

PN532_SPI._wait_ready: fixed command overwriting #29

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PN532_SPI._wait_ready: fixed command overwriting 
Use separate buffer for sending and receiving form SPI
This fixes #28
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@basil-huber
basil-huber committed Jan 5, 2020
commit 3da8e1652c3926c505e411911d7c3e19d61317f8
8 changes: 4 additions & 4 deletions adafruit_pn532/spi.py
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Original file line number Diff line number Diff line change
Expand Up @@ -78,14 +78,14 @@ def _wakeup(self):

def _wait_ready(self, timeout=1):
"""Poll PN532 if status byte is ready, up to `timeout` seconds"""
status = bytearray([reverse_bit(_SPI_STATREAD), 0])

status_cmd = bytearray([reverse_bit(_SPI_STATREAD), 0x00])
status_response = bytearray([0x00, 0x00])
timestamp = time.monotonic()
with self._spi as spi:
while (time.monotonic() - timestamp) < timeout:
time.sleep(0.02) # required
spi.write_readinto(status, status) #pylint: disable=no-member
if reverse_bit(status[1]) == 0x01: # LSB data is read in MSB
spi.write_readinto(status_cmd, status_response) #pylint: disable=no-member
if reverse_bit(status_response[1]) == 0x01: # LSB data is read in MSB
return True # Not busy anymore!
else:
time.sleep(0.01) # pause a bit till we ask again
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