270 lines
8.6 KiB
Python
270 lines
8.6 KiB
Python
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import datetime
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import logging
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import time
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import RPi.GPIO as GPIO
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import spidev
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class LoraBoardDraguino():
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def __init__(self, frequency, sf):
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assert 7 <= sf <= 12
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self.frequency = frequency
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self.sf = sf
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# pin are given in BCM schema
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self._pin_ss = 25 # GPIO 6
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self._pin_dio0 = 4 # GPIO 7
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self._pin_rst = 17 # GPIO 0
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self._spi_bus = 0
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self._spi_cs = 0 # TODO: Draguino has it's own non-standard CS pin
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self.spi = None
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self._is_sx1272 = None # is set in setup
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def __enter__(self):
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self.setup_device()
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return self
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def __exit__(self, exc_type, exc_val, exc_tb):
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self.teardown_device()
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def _init_pins(self):
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GPIO.setmode(GPIO.BCM)
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GPIO.setup(self._pin_ss, GPIO.OUT)
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GPIO.setup(self._pin_dio0, GPIO.IN)
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GPIO.setup(self._pin_rst, GPIO.OUT)
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# save default values
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#GPIO.output(self._pin_ss, 1)
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#GPIO.output(self._pin_rst, 0)
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def _init_spi(self):
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self.spi = spidev.SpiDev()
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self.spi.open(self._spi_bus, self._spi_cs)
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self.spi.max_speed_hz = 5000000 # TODO: what value works good?
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def setup_device(self):
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self._init_pins()
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self._init_spi()
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GPIO.output(self._pin_rst, 1)
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time.sleep(0.10)
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GPIO.output(self._pin_rst, 0)
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time.sleep(0.10)
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version = self.read_register(SX127x.REG_VERSION)
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if version == 0x22:
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logging.info("SX1272 detected, starting...")
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self._is_sx1272 = True
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else:
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# sx1276?
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GPIO.output(self._pin_rst, 0)
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time.sleep(0.10)
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GPIO.output(self._pin_rst, 1)
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time.sleep(0.10)
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version = self.read_register(SX127x.REG_VERSION)
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if version == 0x12:
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logging.info("SX1276 detected, starting...")
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self._is_sx1272 = False
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else:
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logging.critical("Unrecognized transceiver")
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raise RuntimeError("Unrecognized transceiver")
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self.write_register(SX127x.REG_OPMODE, SX127x.SX72_MODE_LONG_RANGE | SX127x.SX72_MODE_SLEEP)
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frf = int((self.frequency << 19) / 32000000)
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self.write_register(SX127x.REG_FRF_MSB, (frf >> 16) & 0xFF)
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self.write_register(SX127x.REG_FRF_MID, (frf >> 8) & 0xFF)
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self.write_register(SX127x.REG_FRF_LSB, frf & 0xFF)
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#self.write_register(SX127x.REG_SYNC_WORD, 0x34); # LoRaWAN public sync word
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if self._is_sx1272:
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if self.sf == 11 or self.sf == 12:
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self.write_register(SX127x.REG_MODEM_CONFIG, 0x0B)
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else:
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self.write_register(SX127x.REG_MODEM_CONFIG, 0x0A)
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self.write_register(SX127x.REG_MODEM_CONFIG2, (self.sf << 4) | 0x04)
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else:
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if self.sf == 11 or self.sf == 12:
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self.write_register(SX127x.REG_MODEM_CONFIG3, 0x0C)
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else:
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self.write_register(SX127x.REG_MODEM_CONFIG3, 0x04)
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self.write_register(SX127x.REG_MODEM_CONFIG, 0x72) # 125kHz 4/5
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self.write_register(SX127x.REG_MODEM_CONFIG2, (self.sf << 4) | 0x04) # enable CTC
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if self.sf == 10 or self.sf == 11 or self.sf == 12:
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self.write_register(SX127x.REG_SYMB_TIMEOUT_LSB, 0x05)
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else:
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self.write_register(SX127x.REG_SYMB_TIMEOUT_LSB, 0x08)
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self.write_register(SX127x.REG_MAX_PAYLOAD_LENGTH, 0x80)
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self.write_register(SX127x.REG_PAYLOAD_LENGTH, 0x80)
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#self.write_register(SX127x.REG_HOP_PERIOD, 0xFF)
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self.write_register(SX127x.REG_FIFO_ADDR_PTR, self.read_register(SX127x.REG_FIFO_RX_BASE_AD))
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self.write_register(SX127x.REG_PA_CONFIG, 0) # set to a very low value
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# Set Continuous Receive Mode
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self.write_register(SX127x.REG_LNA, SX127x.LNA_MAX_GAIN)
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self.write_register(SX127x.REG_OPMODE, SX127x.SX72_MODE_LONG_RANGE | SX127x.SX72_MODE_RX_CONTINUOS)
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def teardown_device(self):
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logging.info("tear down transceiver...")
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GPIO.cleanup()
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self.spi.close()
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def read_register(self, register):
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GPIO.output(self._pin_ss, 0)
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value = self.spi.xfer([register & 0x7F, 0])[1]
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GPIO.output(self._pin_ss, 1)
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return value
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def write_register(self, register, value):
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GPIO.output(self._pin_ss, 0)
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self.spi.xfer([register | 0x80, value])
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GPIO.output(self._pin_ss, 1)
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def write_bulk_register(self, register, values):
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GPIO.output(self._pin_ss, 0)
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self.spi.xfer([register | 0x80] + list(values))
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GPIO.output(self._pin_ss, 1)
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def set_mode_rx(self):
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self.write_register(SX127x.REG_OPMODE, SX127x.SX72_MODE_LONG_RANGE | SX127x.SX72_MODE_RX_CONTINUOS)
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def receive_package(self):
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self.write_register(SX127x.REG_IRQ_FLAGS, 0x40) # clear rxDone
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irqflags = self.read_register(SX127x.REG_IRQ_FLAGS)
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if irqflags & 0x20:
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logging.warning("CRC error")
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self.write_register(SX127x.REG_IRQ_FLAGS, 0x20)
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crc = False
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#return {'datetime': datetime.datetime.now(),
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# 'crc': False} # TODO: still get payload?
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else:
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crc = True
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current_addr = self.read_register(SX127x.REG_FIFO_RX_CURRENT_ADDR)
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received_count = self.read_register(SX127x.REG_RX_NB_BYTES)
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self.write_register(SX127x.REG_FIFO_ADDR_PTR, current_addr)
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payload = bytearray()
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for _ in range(received_count):
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payload.append(self.read_register(SX127x.REG_FIFO))
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return {'datetime': datetime.datetime.utcnow().replace(tzinfo=datetime.timezone.utc),
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'crc': crc,
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'pkt_snr': self.pkt_snr,
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'pkt_rssi': self.pkt_rssi,
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'rssi': self.rssi,
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'payload': bytes(payload)}
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def send_package(self, msg):
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assert type(msg) == bytes
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assert len(msg) <= 255
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# TODO: wait until send (done at end)
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self.write_register(SX127x.REG_OPMODE, SX127x.SX72_MODE_STANDBY)
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self.write_register(SX127x.REG_FIFO_ADDR_PTR, self.read_register(SX127x.REG_FIFO_TX_BASE_AD))
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self.write_register(SX127x.REG_PAYLOAD_LENGTH, len(msg))
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self.write_bulk_register(SX127x.REG_FIFO, msg)
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self.write_register(SX127x.REG_OPMODE, SX127x.SX72_MODE_TX)
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self.wait_until_send()
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def wait_until_send(self):
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while self.read_register(SX127x.REG_IRQ_FLAGS) & 0x08 == 0:
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pass # busy waiting
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self.write_register(SX127x.REG_IRQ_FLAGS, 0x08) # Clear TX DONE
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@property
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def pkt_snr(self):
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snr_value = self.read_register(SX127x.REG_PKT_SNR_VALUE)
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if snr_value & 0x80:
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snr_value = ((~snr_value + 1) & 0xFF) >> 2
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return -snr_value
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else:
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return (snr_value & 0xFF) >> 2
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@property
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def pkt_rssi(self):
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if self._is_sx1272:
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rssicorr = 139
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else:
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rssicorr = 157
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return self.read_register(0x1A) - rssicorr
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@property
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def rssi(self):
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if self._is_sx1272:
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rssicorr = 139
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else:
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rssicorr = 157
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return self.read_register(0x1B) - rssicorr
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class SX127x:
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REG_FIFO = 0x00
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REG_FRF_MSB = 0x06
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REG_FRF_MID = 0x07
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REG_FRF_LSB = 0x08
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REG_PA_CONFIG = 0x09
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REG_LNA = 0x0C
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REG_FIFO_ADDR_PTR = 0x0D
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REG_FIFO_TX_BASE_AD = 0x0E
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REG_FIFO_RX_BASE_AD = 0x0F
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REG_RX_NB_BYTES = 0x13
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REG_OPMODE = 0x01
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REG_FIFO_RX_CURRENT_ADDR = 0x10
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REG_IRQ_FLAGS = 0x12
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REG_DIO_MAPPING_1 = 0x40
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REG_DIO_MAPPING_2 = 0x41
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REG_MODEM_CONFIG = 0x1D
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REG_MODEM_CONFIG2 = 0x1E
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REG_MODEM_CONFIG3 = 0x26
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REG_SYMB_TIMEOUT_LSB = 0x1F
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REG_PKT_SNR_VALUE = 0x19
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REG_PAYLOAD_LENGTH = 0x22
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REG_IRQ_FLAGS_MASK = 0x11
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REG_MAX_PAYLOAD_LENGTH = 0x23
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REG_HOP_PERIOD = 0x24
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REG_SYNC_WORD = 0x39
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REG_VERSION = 0x42
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SX72_MODE_LONG_RANGE = 0x80
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SX72_MODE_SLEEP = 0x00
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SX72_MODE_STANDBY = 0x01
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SX72_MODE_FSTX = 0x02
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SX72_MODE_TX = 0x03
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SX72_MODE_FSRX = 0x04
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SX72_MODE_RX_CONTINUOS = 0x05
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SX72_MODE_RX_SINGLE = 0x06
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LNA_MAX_GAIN = 0x23
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LNA_OFF_GAIN = 0x00
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LNA_LOW_GAIN = 0x20
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