Python LT8900 via SPI

# |-------+-------+-------+-------+-------+-------+--------|
# | P1-17 | P1-18 | P1-21 | P1-19 | P1-23 | P1-24 | P1-25  |
# -________________________________________________________-
#                     Raspberry Pi

import spidev
import time


class radio:
	__register_map = [
		{'name': "Unknown"}, # 0
		{'name': "Unknown"}, # 1
		{'name': "Unknown"}, # 2
		{                    # 3

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

		return None

	def __debug(self, message):
		print("DEBUG: " + message)
		return None

	def __reset_device(self):
		if self.__config is not None:
			if self.__config['reset_command'] is not None:
				return self.__config['reset_command']()
		return None

		value2 = self.get_register(1);

		if value1 == 0x6fe0 and value2 == 0x5681:
			return True
		return False

	def __set_defaults(self):
		self.put_register_bits('radio_state', {'tx_enabled': 0, 'rx_enabled': 0, 'channel': 76})
		self.put_register_bits('power', {'current': 4, 'gain': 0})
		self.put_register_bits('rssi_power', {'mode': 0})
		self.put_register_bits('crystal', {'trim_adjust': 0})
		self.put_register_bits('packet_config', {
			'preamble_len': 2,
			'syncword_len': 1,
			'trailer_len': 0,
			'packet_type': 0,
			'fec_type': 0,
			'br_clock_sel': 0
		})
		self.put_register_bits('chip_power', {
			'power_down': 0,
			'sleep_mode': 0,
			'br_clock_on_sleep': 0,
			'rexmit_times': 3,
			'miso_tri_opt': 0,
			'scramble_value': 0
		})
		self.put_register_bits('thresholds', {
			'fifo_empty_threshold': 8,
			'fifo_full_threshold': 16,
			'syncword_error_bits': 2
		})
		self.put_register_bits('format_config', {
			'crc_enabled': 1,
			'scramble_enabled': 0,
			'packet_length_encoded': 1,
			'auto_term_tx': 1,
			'auto_ack': 0,
			'pkt_fifo_polarity': 0,
			'crc_initial_data': 0
		})
		self.put_register_bits('scan_rssi', {'channel': 63, 'ack_time': 176})
		self.put_register_bits('gain_block', {'enabled': 1})
		self.put_register_bits('vco_calibrate', {'enabled': 1})
		self.put_register_bits('scan_rssi_state', {'enabled': 0, 'channel_offset': 0, 'wait_time': 15})

		return True

	def __put_register_high_low(self, reg, high, low, delay = 7):
		reg = self.__register_number(reg)
		result = self.__spi.xfer([reg, high, low], self.__spi.max_speed_hz, delay)

		if reg & 0x80 == 0x80:

		self.put_register_bits('radio_state', state)

		return state

	def set_syncword(self, 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:
			self.put_register("syncword_0", syncword[0])
		elif len(syncword) == 2:
			self.put_register("syncword_0", syncword[1])
			self.put_register("syncword_3", syncword[0])
		elif len(syncword) == 3:
			self.put_register("syncword_0", syncword[2])
			self.put_register("syncword_2", syncword[1])
			self.put_register("syncword_3", syncword[0])
		elif len(syncword) == 4:
			self.put_register("syncword_0", syncword[3])
			self.put_register("syncword_1", syncword[2])
			self.put_register("syncword_2", syncword[1])
			self.put_register("syncword_3", syncword[0])
		elif len(syncword) > 4:
			raise ValueError("SyncWord length must be less than 5")

		return None

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

		# Initialize the transmitter

			'clear_read': 1,
			'clear_write': 1
		})

		# Format message to send to fifo
		## XXX: TODO: Length encoding is optional, should check register
		message = [self.__register_number('fifo'), len(message)] + message
		log_message = [] + message

		# Transfer the message
		result = self.__spi.xfer(message, self.__spi.max_speed_hz, 10)
		self.__debug("Writing: {} = {}".format(log_message, result))

		# Tell the radio to transmit the FIFO buffer to the specified channel
		self.put_register_bits('radio_state', {
			'tx_enabled': 1,
			'rx_enabled': 0,
			'channel': channel
		})

		# Wait for buffer to empty
		# XXX: Untested
		while True:
			radio_status = self.get_register_bits('status')
			self.__debug("radio_status={}".format(radio_status))

			if radio_status['fifo_flag'] == 0:
				break
			time.sleep(0.1)

		return True

	def multi_transmit(self, message, channels, retries = 3):
		for i in range(retries):
			for channel in channels:
				if not self.transmit(message, channel):
					return False
				time.sleep(0.1 / retries)
		return True

	def start_listening(self, channel):
		# Initialize the receiver
		self.put_register_bits('radio_state', {
			'tx_enabled': 0,
			'rx_enabled': 0,
			'channel': 0
		})

		self.put_register_bits('fifo_state', {
			'clear_read': 1,
			'clear_write': 1
		})

		# Go into listening mode
		self.put_register_bits('radio_state', {
			'tx_enabled': 0,
			'rx_enabled': 1,
			'channel': channel
		})

		return True

	def receive(self, channel = None, wait = False, length = None):
		if wait:
			if channel is None:
				state = self.get_register_bits('radio_state')
				channel = state['channel']

			self.__start_listening(channel)

		message = []

		while True:
			radio_status = self.get_register_bits('status')
			if radio_status['packet_flag'] == 0:
				if wait:
					time.sleep(0.1)
					continue
				else:
					return None

			if radio_status['crc_error'] == 1:
				# Handle invalid packet ?
				# XXX:TODO: Is this sufficient ?
				self.__start_listening(channel)
				continue

			# Data is available, read it from the FIFO register
			# The first result will include the length
			# XXX *IF* length encoding is enabled ?
			fifo_data = self.get_register('fifo')
			message_length = fifo_data >> 8

			# Keep track of the total message length to truncate it
			final_message_length = message_length

			message += [fifo_data & 0xff]
			message_length -= 1

			# Read subsequent bytes from the FIFO register until
			# there are no more bytes to read
			while message_length > 0:
				fifo_data = self.get_register('fifo')
				message += [fifo_data >> 8, fifo_data & 0xff]
				message_length -= 2

			# Truncate the message to its final size, since we have
			# to read in 16-bit words, we may have an extra byte
			message = message[0:final_message_length]
			break

		return message