Python LT8900 via SPI

	def __init__(self, spi_bus, spi_dev, config = None):
		spi = spidev.SpiDev()
		spi.open(spi_bus, spi_dev)
		self._spi = spi

		self._dequeue_thread = None
		self._last_syncword = None

		self.configure(config, update = False)

		if len(self._register_map) != 53:
			raise ValueError('Inconsistent register map!')

		self._software_tx_queue = {}

		return None

	def __del__(self):
		self._debug('Deleting object')
		self._config['use_software_tx_queue'] = False
		self._spi.close()

	def _debug(self, message):
		if self._config is not None and 'debug_log_command' in self._config:
			self._config['debug_log_command'](message)
		return None

			mask = ((1 << (bit_range[1] - bit_range[0] + 1)) - 1) << bit_range[0]
			key_value = (value & mask) >> bit_range[0]
			result[key] = key_value

		# Return the filled in structure
		return result

	def configure(self, config, update = True):
		if config is None:
			config = {}

		if update:
			self._config.update(config)
		else:
			self._config = config

		with self._get_mutex():
			self._spi.max_speed_hz = self._config.get('frequency', 4000000)
			self._spi.bits_per_word = self._config.get('bits_per_word', 8)
			self._spi.cshigh = self._config.get('csigh', False)
			self._spi.no_cs  = self._config.get('no_cs', False)
			self._spi.lsbfirst = self._config.get('lsbfirst', False)
			self._spi.threewire = self._config.get('threewire', False)
			self._spi.mode = self._config.get('mode', 1)

		# If using a queue, start a thread to run the queue
		if self._should_use_queue():
			if self._dequeue_thread is None:
				self._dequeue_thread = threading.Thread(target = self._run_queue, daemon = True)
				self._software_tx_queue_mutex = threading.Lock()
				self._dequeue_thread.start()
		else:
			if self._dequeue_thread is not None:
				self._debug("Joining existing thread to wait for termination")
				self._dequeue_thread.join()
				self._dequeue_thread = None
				self._software_tx_queue_mutex = None

		return None

	def initialize(self):
		self._reset_device()

		self._set_defaults()

		if not self._check_radio():
			return False
		return True

	def set_channel(self, channel):
		state = self.get_register_bits('radio_state')
		state['channel'] = channel

		self.put_register_bits('radio_state', state)

		return state

	def set_syncword(self, syncword, force = False, submit_queue = '__DEFAULT__'):
		# If queuing is being used, just store this message
		if submit_queue is not None and self._should_use_queue():
			self._enqueue(submit_queue, syncword, None, None, post_delay = 0)
			return None

		# Do not set the syncword again if it's not needed
		if not force:
			if self._last_syncword is not None:
				if syncword == self._last_syncword:
					return None

		self._last_syncword = syncword

		packet_config = self.get_register_bits('packet_config')
		packet_config['syncword_len'] = len(syncword) - 1

		self.put_register_bits('packet_config', packet_config)

		if len(syncword) == 1:

		with self._get_mutex(lock):
			result = self._spi.xfer(new_message, self._spi.max_speed_hz, 10)

		self._debug("Writing: {} = {}".format(log_message, result))

		return new_message

	def transmit(self, message, channel = None, lock = True, post_delay = 0, syncword = None, submit_queue = '__DEFAULT__'):
		# If we are using a radio transmit queue, just queue this message
		# (unless we are called from the dequeue procedure)
		if submit_queue is not None and self._should_use_queue():
			if syncword is None:
				syncword = self._last_syncword
			self._enqueue(submit_queue, syncword, message, channel, post_delay = post_delay)
			return True

		sent_packet = True

		with self._get_mutex(lock):
			# Set the syncword
			if syncword is not None:
				self.set_syncword(syncword, submit_queue = None)

			if channel is None:
				state = self.get_register_bits('radio_state')
				channel = state['channel']

			# Initialize the transmitter
			self.put_register_bits('radio_state', {

				if radio_status['framer_status'] == 0:
					sent_packet = False
					break
				time.sleep(0.001)

		if post_delay != 0:
			raise ValueError('No sleeping allowed') # XXX
			time.sleep(post_delay)

		return sent_packet

	def multi_transmit(self, message, channels, retries = 3, delay = 0.1, syncword = None, submit_queue = '__DEFAULT__'):
		delay = delay / len(channels)
		for channel in channels:
			for i in range(retries):
				if not self.transmit(message, channel, post_delay = delay, syncword = syncword, submit_queue = submit_queue):
					return False

		return True

	def _enqueue(self, submit_queue, syncword, message, channel, post_delay = 0):
		with self._software_tx_queue_mutex:
			if submit_queue not in self._software_tx_queue:
				self._software_tx_queue[submit_queue] = []

			if len(self._software_tx_queue[submit_queue]) == 0:
				dispatch_time = time.time()
			else:
				last_item = self._software_tx_queue[submit_queue][-1]
				dispatch_time = last_item['time'] + last_item['post_delay']

			self._software_tx_queue[submit_queue].append({
				'syncword': syncword,
				'message': message,
				'channel': channel,
				'time': dispatch_time,
				'post_delay': post_delay

			})

		return None

	def _run_queue(self):
		self._debug("Started run_queue process")





		sleep_time = 0
		while True:
			self._debug("Sleeping for {} seconds".format(sleep_time))
			time.sleep(sleep_time)
			with self._software_tx_queue_mutex:
				for queue in self._software_tx_queue:
					self._debug("Running the queue named {}: {} items left".format(queue, len(self._software_tx_queue[queue])))
			item_count = self._run_queue_once()
			self._debug("Completed running the queue, {} items left (continue queue = {})".format(item_count, self._should_use_queue()))

			if item_count == 0:
				# If the queue is empty and we are no longer queuing
				# events, exit this function (which should be joined)
				if not self._should_use_queue():
					self._debug("Request to stop run_queue process, exiting")
					return None

				# If there are no events, wait a bit
				# longer before trying again
				sleep_time = 0.5
				continue

			# If there are more events to process, try again in 1ms
			sleep_time = 0.001

		return None

	def _run_queue_once(self):
		now = time.time()
		to_transmit = []
		remaining_items = 0
		with self._software_tx_queue_mutex:
			for submit_queue in self._software_tx_queue:
				new_software_tx_queue = []
				for item in self._software_tx_queue[submit_queue]:




					if item['time'] <= now:
						item['from_queue'] = submit_queue
						to_transmit.append(item)
						continue
					else:
						new_software_tx_queue.append(item)
						remaining_items += 1



				self._software_tx_queue[submit_queue] = new_software_tx_queue


		default_syncword = None

		with self._get_mutex():
			for item in to_transmit:
				self._debug("Transmitting item {}".format(item))
				syncword = item['syncword']
				message = item['message']
				channel = item['channel']

				if syncword is not None:
					default_syncword = syncword
				else:
					syncword = default_syncword

				if message is None or channel is None:
					continue

				for retry in range(3):
					if self.transmit(message, channel, lock = False, submit_queue = None, syncword = syncword):
						break

		return remaining_items
		
	def start_listening(self, channel):
		# Initialize the receiver
		self.stop_listening()

		# Go into listening mode
		self.put_register_bits('radio_state', {