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PN532_SPI._wait_ready: fixed command overwriting

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Use separate buffer for sending and receiving form SPI
This fixes #28
This commit is contained in:
Basil Huber 2020-01-05 21:58:13 +01:00
parent 34c3dfcf76
commit 3da8e1652c
1 changed files with 4 additions and 4 deletions
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8
adafruit_pn532/spi.py
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@ -78,14 +78,14 @@ class PN532_SPI(PN532):
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