1  # Example using Interrupts to send a message and then wait indefinitely for messages
 2  # to be received. Interrupts are used only for receive. sending is done with polling.
 3  # This example is for systems that support interrupts like the Raspberry Pi with "blinka"
 4  # CircuitPython does not support interrupts so it will not work on  Circutpython boards
 5  # Author: Tony DiCola, Jerry Needell
 6  import time
 7  import board
 8  import busio
 9  import digitalio
10  import RPi.GPIO as io
11  import adafruit_rfm9x
12  
13  
14  # setup interrupt callback function
15  def rfm9x_callback(rfm9x_irq):
16      global packet_received  # pylint: disable=global-statement
17      print("IRQ detected ", rfm9x_irq, rfm9x.rx_done)
18      # check to see if this was a rx interrupt - ignore tx
19      if rfm9x.rx_done:
20          packet = rfm9x.receive(timeout=None)
21          if packet is not None:
22              packet_received = True
23              # Received a packet!
24              # Print out the raw bytes of the packet:
25              print("Received (raw bytes): {0}".format(packet))
26              print([hex(x) for x in packet])
27              print("RSSI: {0}".format(rfm9x.last_rssi))
28  
29  
30  # Define radio parameters.
31  RADIO_FREQ_MHZ = 915.0  # Frequency of the radio in Mhz. Must match your
32  # module! Can be a value like 915.0, 433.0, etc.
33  
34  # Define pins connected to the chip, use these if wiring up the breakout according to the guide:
35  CS = digitalio.DigitalInOut(board.CE1)
36  RESET = digitalio.DigitalInOut(board.D25)
37  
38  # Initialize SPI bus.
39  spi = busio.SPI(board.SCK, MOSI=board.MOSI, MISO=board.MISO)
40  
41  # Initialze RFM radio
42  rfm9x = adafruit_rfm9x.RFM9x(spi, CS, RESET, RADIO_FREQ_MHZ)
43  
44  # Note that the radio is configured in LoRa mode so you can't control sync
45  # word, encryption, frequency deviation, or other settings!
46  
47  # You can however adjust the transmit power (in dB).  The default is 13 dB but
48  # high power radios like the RFM95 can go up to 23 dB:
49  rfm9x.tx_power = 23
50  
51  # configure the interrupt pin and event handling.
52  RFM9X_G0 = 22
53  io.setmode(io.BCM)
54  io.setup(RFM9X_G0, io.IN, pull_up_down=io.PUD_DOWN)  # activate input
55  io.add_event_detect(RFM9X_G0, io.RISING)
56  io.add_event_callback(RFM9X_G0, rfm9x_callback)
57  
58  packet_received = False
59  # Send a packet.  Note you can only send a packet up to 252 bytes in length.
60  # This is a limitation of the radio packet size, so if you need to send larger
61  # amounts of data you will need to break it into smaller send calls.  Each send
62  # call will wait for the previous one to finish before continuing.
63  rfm9x.send(bytes("Hello world!\r\n", "utf-8"), keep_listening=True)
64  print("Sent Hello World message!")
65  
66  # Wait to receive packets.  Note that this library can't receive data at a fast
67  # rate, in fact it can only receive and process one 252 byte packet at a time.
68  # This means you should only use this for low bandwidth scenarios, like sending
69  # and receiving a single message at a time.
70  print("Waiting for packets...")
71  while True:
72      time.sleep(0.1)
73      if packet_received:
74          print("received message!")
75          packet_received = False