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Fix SPI read_passive_target timeout

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tgikal 2019-07-03 15:12:18 -04:00 • committed by GitHub
parent 3f759879c8
commit 5c75384f83
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1 changed files with 10 additions and 5 deletions
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15
adafruit_pn532/spi.py
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@ -51,7 +51,12 @@ _SPI_READY = const(0x01)
def reverse_bit(num): def reverse_bit(num):
"""Turn an LSB byte to an MSB byte, and vice versa. Used for SPI as """Turn an LSB byte to an MSB byte, and vice versa. Used for SPI as
it is LSB for the PN532, but 99% of SPI implementations are MSB only!""" it is LSB for the PN532, but 99% of SPI implementations are MSB only!"""
return int('{:08b}'.format(num)[::-1], 2) result = 0
for _ in range(8):
result <<= 1
result += (num & 1)
num >>= 1
return result
class PN532_SPI(PN532): class PN532_SPI(PN532):
"""Driver for the PN532 connected over SPI. Pass in a hardware or bitbang """Driver for the PN532 connected over SPI. Pass in a hardware or bitbang
@ -78,11 +83,11 @@ class PN532_SPI(PN532):
timestamp = time.monotonic() timestamp = time.monotonic()
with self._spi as spi: with self._spi as spi:
while (time.monotonic() - timestamp) < timeout: while (time.monotonic() - timestamp) < timeout:
time.sleep(0.02) # required (not needed when tested on rPi 3) time.sleep(0.02) # required
spi.write_readinto(status, status) #pylint: disable=no-member spi.write_readinto(status, status) #pylint: disable=no-member
if reverse_bit(status[1]) == 0x01: # LSB data is read in MSB if reverse_bit(status[1]) == 0x01: # LSB data is read in MSB
return True # Not busy anymore! return True # Not busy anymore!
else: # (not needed when tested on rPi 3) else:
time.sleep(0.01) # pause a bit till we ask again time.sleep(0.01) # pause a bit till we ask again
# We timed out! # We timed out!
return False return False
@ -95,7 +100,7 @@ class PN532_SPI(PN532):
frame[0] = reverse_bit(_SPI_DATAREAD) frame[0] = reverse_bit(_SPI_DATAREAD)
with self._spi as spi: with self._spi as spi:
time.sleep(0.02) # required (not needed when tested on rPi 3) time.sleep(0.02) # required
spi.write_readinto(frame, frame) #pylint: disable=no-member spi.write_readinto(frame, frame) #pylint: disable=no-member
for i, val in enumerate(frame): for i, val in enumerate(frame):
frame[i] = reverse_bit(val) # turn LSB data to MSB frame[i] = reverse_bit(val) # turn LSB data to MSB
@ -111,5 +116,5 @@ class PN532_SPI(PN532):
if self.debug: if self.debug:
print("Writing: ", [hex(i) for i in rev_frame]) print("Writing: ", [hex(i) for i in rev_frame])
with self._spi as spi: with self._spi as spi:
time.sleep(0.02) # required (not needed when tested on rPi 3) time.sleep(0.02) # required
spi.write(bytes(rev_frame)) #pylint: disable=no-member spi.write(bytes(rev_frame)) #pylint: disable=no-member