tgikal
commented
5 years ago The SPI and I2C interfaces use an entirely different backend. The problem looks like it's occurring in adafruit_pn532/spi.py -> _wait_ready.
I believe it's related to the with self._spi as spi: statement calling the class each iteration of the while loop:
def _wait_ready(self, timeout=1):
"""Poll PN532 if status byte is ready, up to `timeout` seconds"""
status = bytearray([reverse_bit(_SPI_STATREAD), 0])
timestamp = time.monotonic()
while (time.monotonic() - timestamp) < timeout:
with self._spi as spi:
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
return True # Not busy anymore!
else:
time.sleep(0.01) # pause a bit till we ask again
# We timed out!
return FalseChanging the while loop around a bit seems to have corrected it:
def _wait_ready(self, timeout=1):
"""Poll PN532 if status byte is ready, up to `timeout` seconds"""
status = bytearray([reverse_bit(_SPI_STATREAD), 0])
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
return True # Not busy anymore!
else:
time.sleep(0.1) # pause a bit till we ask again
# We timed out!
return False
caternuson
BraindeadBZH
Hi,
When in SPI mode calling read_passive_target with a timeout, a NFC tag is only detect at the very beginning of the poll. This is not the case with i2c which detects tags through all the duration of the timeout.