beacon.py

#!/usr/bin/env python

""" Beacon Class """

""" Thomas Verbeke - thomas.verbeke@vub.ac.be
    Send out data + counter value
    
    Tested with Embed LoRa Module (SX1276 Semtech chip)
   
"""

import sys
from time import sleep
from SX127x.LoRa import *
from SX127x.board_config import BOARD, GPIO


BOARD.setup() # setup GPIO's

class LoRaBeacon(LoRa):

    tx_counter = 0

    def __init__(self, verbose=False):
        super(LoRaBeacon, self).__init__(verbose)
        self.set_mode(MODE.SLEEP)
        self.set_dio_mapping([1,0,0,0,0,0]) #DIO0 is set to TxDone

        """ DIO Mapping     DIO5        DIO4        DIO3    DIO2                DIO1        DIO0
                            ModeReady   CadDetected CadDone FhssChangeChannel   RxTimeout   TxDone
        """

    def on_rx_done(self):  # will not be called trough DIO (because it is mapped to TxDone) 
  	print("\n(RxDone) Packet Received")
	
	print(self.get_irq_flags()) 
	print('num bytes payload', self.get_rx_nb_bytes())

	payload = self.read_payload(nocheck=True)
        print('Payload:', payload,map(hex, payload)) 

	decoded_msg_str = ''.join(map(chr,payload)) # convert byte to string and join
	print (decoded_msg_str)

    def on_tx_done(self):
	global msg
	print("\n(TxDone) Interrupt generated")
	self.tx_counter +=1
	sleep(2)
	
	self.set_mode(MODE.STDBY)
	sleep(0.001)
	self.clear_irq_flag_TxDone()
        sys.stdout.flush()

	b_msg = list(bytearray(msg,'utf-8'))

	self.set_payload_length(len(b_msg)) # set message length
        base_addr = self.get_fifo_tx_base_addr()
        self.set_fifo_addr_ptr(base_addr)

	self.spi.xfer([REG.LORA.FIFO | 0x80] + b_msg)[1:]
	
	print "Sending Message %s" % self.tx_counter
	self.set_mode(MODE.TX)  # send Message
	
    def on_cad_done(self):
        print("\non_CadDone")
        print(self.get_irq_flags())

    def on_rx_timeout(self):
        print("\non_RxTimeout")
        print(self.get_irq_flags())

    def on_valid_header(self):
        print("\non_ValidHeader")
        print(self.get_irq_flags())

    def on_payload_crc_error(self):
        print("\non_PayloadCrcError")
        print(self.get_irq_flags())

    def on_fhss_change_channel(self):
        print("\non_FhssChangeChannel")
        print(self.get_irq_flags())

    def start(self):
	global msg

	sys.stdout.write("\rstart")
        self.tx_counter = 0

	b_msg = list(bytearray(msg,'utf-8'))

	self.set_payload_length(len(b_msg)) # set message length

        base_addr = self.get_fifo_tx_base_addr()
        self.set_fifo_addr_ptr(base_addr)

	self.spi.xfer([REG.LORA.FIFO | 0x80] + b_msg)[1:]
	
	print "\rSending Message %s" % self.tx_counter
	self.set_mode(MODE.TX)  # send Message
        while True:
		sleep(0.5)

msg = "Hello"

lora = LoRaBeacon(verbose=False)

lora.set_pa_config(pa_select=0)
lora.set_coding_rate(CODING_RATE.CR4_6)
lora.set_implicit_header_mode(False)

print(lora)
try: input("Press enter to start...")
except: pass

try:
    lora.start()
except KeyboardInterrupt:
    sys.stdout.flush()
    print("")
    sys.stderr.write("KeyboardInterrupt\n")
finally:
    sys.stdout.flush() # Calling sys.stdout.flush() forces it to "flush" the buffer, meaning that it will write everything in the buffer to the terminal
    print("")
    lora.set_mode(MODE.SLEEP)
    print(lora)
    BOARD.teardown() # Cleanup GPIO and SpiDev