├── .gitignore
├── LICENSE
├── README.md
├── lora.py
├── misc
├── airtime_calculator.jpg
├── airtime_calculator.zip
├── console_output.png
├── fhss.jpg
├── issue
│ └── 8
│ │ └── setup.jpg
├── receiver.ipynb
└── sender.ipynb
├── receiver
├── lora.py
└── receiver.py
└── sender
├── lora.py
└── sender.py
/.gitignore:
--------------------------------------------------------------------------------
1 | .vscode
2 | .picowgo
3 |
--------------------------------------------------------------------------------
/LICENSE:
--------------------------------------------------------------------------------
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/README.md:
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1 | This repo implements more than basic SX1276 operations while [Learn_SX1276](https://github.com/xg590/Learn_SX1276) shows all the basics.
2 | ## SX1276
3 | MicroPython Library for SX1276 LoRa radio modem
4 | ## Features
5 | * MAC layer (half-duplex).
6 | * One SX1276 can send a "REQ" packet (in a blocking way) and expect a specified SX1276 to respond with an "ACK" packet. This process is handled by this library.
7 | * One SX1276 can send a "BRD" packet (in a non-blocking way) and expect no "ACK" reply.
8 | * Implement FHSS (first?)
9 | * FCC mandates frequency hopping if dwell time is above the threshold 400ms.
10 | * Large spreading factor and narrow bandwidth can significantly prolong the dwell time so that freq hopping is necessary for transmiiting large packet.
11 | ## Usage
12 | * Upload lora.py to MCUs (Heltec WiFi LoRa 32 V2)
13 | * Run [sender.py](sender/sender.py) and [receiver.py](receiver/receiver.py) on two separate MCUs
14 | ## My dev environment
15 | * Two MCUs with SX1276 (ESP32: Heltec WiFi LoRa 32 V2)
16 | * Flash MCUs with MicroPython
17 | * Connect two MCUs to a Linux Machine with VSCode via USB
18 | * Install Pico-W-Go extension for VSCode
19 | * Open sender/receiver folders in two VSCode windows
20 | * Configure sender/receiver projects for Pico-W-Go
21 | * Specify the "Manual Com Device" in Pico-W-Go and restart the Pico-W-Go
22 | * Play with Pico-W-Go commands
23 | ## Console Output of sample code
24 | 
25 | ## FHSS
26 | * To prove the point of frequency hopping, I use a RTL-SDR to monitor the spectrum. In following waterfall diagram, we see the signal hops between 914 and 916MHz as I programmed it to be.
27 | 
28 | * FHSS is not necessary if the message is short. For example, a 29Bytes packet can be transmitted under 400ms, given parameters {SF:10, BW:125kHz, CR:4/5, Header: Explicit , Preamble: 6}.
29 | 
30 | Download the above air time [calculator](misc/airtime_calculator.zip)
31 |
32 | ## Note
33 | * FHSS feature can be turned off by only specifying one frequency in channels2Hopping / FHSS_list.
34 | * It is meaningless to do Channel Activity Detection (CAD) before Tx because SX1276 only match elusive preambles which last few milliseconds. No good solution to do Listen Before Talk or CSMA.
--------------------------------------------------------------------------------
/lora.py:
--------------------------------------------------------------------------------
1 | import time, urandom, struct
2 | from machine import Pin, SPI
3 |
4 | class SX1276:
5 | def __init__(self, RST_Pin, CS_Pin, SPI_CH, SCK_Pin, MOSI_Pin, MISO_Pin, DIO0_Pin, DIO1_Pin, SRC_Id, FHSS_list, plus20dBm=False, debug=False):
6 | self.src_id = SRC_Id # id of packet sender
7 | self.pkt_id = 0 # pkt_id is a random packet id. Why we need this ? If we ask the receiver return an acknowledgement, how do we know which packet it is acknowledging?
8 | self.pkt_type = 0
9 | # REQ or Request : Sender needs an ACK packet from the receiver as the response to this REQ packet
10 | # ACK or Acknowledge: Receiver sends this ACK response
11 | # BRD or Broadcast : Sender needs no ACK response
12 | self.PKT_TYPE = {'REQ':0, 'ACK':1, 'BRD':2}
13 | self.header_fmt = 'HHHH' # src_id, dst_id, pkt_id, pkt_type
14 | self.header_size = struct.calcsize(self.header_fmt)
15 | self._mode = None
16 | self.FHSS_list = FHSS_list
17 | self.debug = debug
18 | self.is_available = False # let the main code know Tx and RxCont is done
19 | ########################
20 | # #
21 | # 1. Reset the modem #
22 | # #
23 | ########################
24 | rst_pin = Pin(RST_Pin, Pin.OUT)
25 | rst_pin.off()
26 | time.sleep(0.01)
27 | rst_pin.on()
28 | time.sleep(0.01)
29 |
30 | #################################
31 | # #
32 | # 2. SPI comm with the modem. #
33 | # #
34 | #################################
35 |
36 | # Tx: Modem's wireless transmittion, Rx: Reception
37 | # Modem communicates with other modem since we command the modem to perform Tx/Rx operations via the SPI interface.
38 | # We disable SPI communication with the modem first, to ensure Tx/Rx operations only happends when we need.
39 | self.cs_pin = Pin(CS_Pin, Pin.OUT)
40 | self.cs_pin.on() # Release board from SPI Bus by bringing it into high impedance status.
41 |
42 | # SPI communication
43 | # See datasheet: Device support SPI mode 0 (polarity & phase = 0) up to a max of 10MHz.
44 | self.spi = SPI(SPI_CH, baudrate=10_000_000, polarity=0, phase=0,
45 | sck=Pin(SCK_Pin), mosi=Pin(MOSI_Pin), miso=Pin(MISO_Pin)
46 | )
47 |
48 | ####################
49 | # #
50 | # 3.Lora #
51 | # #
52 | ####################
53 | self.RegTable = { # register table
54 | 'RegFifo' : 0x00 ,
55 | 'RegOpMode' : 0x01 , # operation mode
56 | 'RegFrfMsb' : 0x06 ,
57 | 'RegFrfMid' : 0x07 ,
58 | 'RegFrfLsb' : 0x08 ,
59 | 'RegPaConfig' : 0x09 ,
60 | 'RegFifoTxBaseAddr' : 0x0e ,
61 | 'RegFifoRxBaseAddr' : 0x0f ,
62 | 'RegFifoAddrPtr' : 0x0d ,
63 | 'RegFifoRxCurrentAddr' : 0x10 ,
64 | 'RegIrqFlags' : 0x12 ,
65 | 'RegRxNbBytes' : 0x13 , # Number of received bytes
66 | 'RegPktSnrValue' : 0x19 ,
67 | 'RegPktRssiValue' : 0x1a ,
68 | 'RegRssiValue' : 0x1b ,
69 | 'RegHopChannel' : 0x1c ,
70 | 'RegModemConfig1' : 0x1d ,
71 | 'RegModemConfig2' : 0x1e ,
72 | 'RegPreambleMsb' : 0x20 ,
73 | 'RegPreambleLsb' : 0x21 ,
74 | 'RegPayloadLength' : 0x22 ,
75 | 'RegHopPeriod' : 0x24 ,
76 | 'RegModemConfig3' : 0x26 ,
77 | 'RegDioMapping1' : 0x40 ,
78 | 'RegVersion' : 0x42 ,
79 | 'RegPaDac' : 0x4d
80 | }
81 |
82 | self.Mode = { # see Table 16 LoRa ® Operating Mode Functionality
83 | 'SLEEP' : 0b000,
84 | 'STANDBY' : 0b001,
85 | 'TX' : 0b011,
86 | 'RXCONTINUOUS' : 0b101,
87 | 'RXSINGLE' : 0b110,
88 | 'CAD' : 0b111,
89 | }
90 |
91 | if True: # code folding
92 | # Choose LoRa mode and Test write/read functions
93 | LongRangeMode = 0b1
94 | # Choose LoRa (instead of FSK) mode for SX1276 and put the module in sleep mode
95 | self.spi_write('RegOpMode', self.Mode['SLEEP'] | LongRangeMode << 7)
96 | # Test read function
97 | assert self.spi_read('RegOpMode') == (self.Mode['SLEEP'] | LongRangeMode << 7), "LoRa initialization failed"
98 |
99 | # Set modem config: bandwidth, coding rate, header mode, spreading factor, CRC, and etc.
100 | # See 4.4. LoRa Mode Register Map
101 | Bw = {'125KHz':0b0111, '500kHz':0b1001}
102 | CodingRate = {5:0b001, 6:0b010, 7:0b011, 8:0b100}
103 | ImplicitHeaderModeOn = {'Implicit':0b1, 'Explicit':0b0}
104 | self.spi_write('RegModemConfig1', Bw['125KHz'] << 4 | CodingRate[5] << 1 | ImplicitHeaderModeOn['Explicit'])
105 |
106 | SpreadingFactor = {7:0x7, 9:0x9, 10:0xA, 12:0xC}
107 | TxContinuousMode = {'normal':0b0, 'continuous':0b1}
108 | RxPayloadCrcOn = {'disable':0b0, 'enable':0b1}
109 | self.spi_write('RegModemConfig2', SpreadingFactor[10] << 4 | TxContinuousMode['normal'] << 3 | RxPayloadCrcOn['enable'] << 2 | 0x00) # Last 0x00 is SymbTimeout(9:8)
110 |
111 | LowDataRateOptimize = {'Disabled':0b0, 'Enabled':0b1}
112 | AgcAutoOn = {'register LnaGain':0b0, 'internal AGC loop':0b1}
113 | self.spi_write('RegModemConfig3', LowDataRateOptimize['Enabled'] << 3 | AgcAutoOn['internal AGC loop'] << 2)
114 |
115 | # Preamble length
116 | self.spi_write('RegPreambleMsb', 0x0) # Preamble can be (2^15)kb long, much longer than payload
117 | self.spi_write('RegPreambleLsb', 0x8) # but we just use 8-byte preamble
118 |
119 | # FHSS
120 | # How does SX1276 chip hop the freq spectrum?
121 | # First, two SX1276 chips were given a same series of frequencies (FHSS_list) in advance.
122 | # One SX1276 is configured as sender and another is receiver.
123 | # The sender is configured to be interrupted (IRQ) by 'TxDone' and 'FhssChangeChannel'
124 | # The receiver is configured to be interrupted by 'RxDone' and 'FhssChangeChannel'
125 | # After the chip spent enough (dwell) time on one frequency channel during Tx or Rx, 'FhssChangeChannel' IRQ is triggered.
126 | # New freq (next unused element in FHSS_list) is set in the 'FhssChangeChannel' IRQ handler.
127 | # After enough channels are hopped, Tx/Rx is done and TxDone/RxDone is triggered.
128 |
129 | # Symbol duration: Tsym = 2^SF / BW
130 | # For example, if SF = 10, BW = 125kHz, then Tsym = 8.192ms
131 | # Given FCC permits a 400ms max dwell time per channel, we must hop at least every 48 symbols
132 | # HoppingPeriod (dwell time on each freq) = FreqHoppingPeriod * Tsym
133 | # In the following code, the chip would hop freq for every 20 symbols.
134 | FreqHoppingPeriod = 20 # Symbol periods between freq hops.
135 | if len(FHSS_list) == 1: # As requested in Issue 8, the FHSS feature can be turned off when one freq is provided.
136 | FreqHoppingPeriod = 0 # Hopping feature is turned off by this line
137 | self.spi_write('RegHopPeriod', FreqHoppingPeriod) # HoppingPeriod = 20 * 8.192ms
138 | FhssPresentChannel = self.spi_read('RegHopChannel')
139 |
140 | # See 4.1.4. Frequency Settings
141 | FXOSC = 32e6 # Freq of XOSC
142 | self.FSTEP = FXOSC / (2**19)
143 |
144 | # Output Power
145 | # If desired output power is within -4 ~ +15dBm, use PA_LF or PA_HF as amplifier.
146 | # Use PA_BOOST as amplifier to output +2 ~ +17dBm continuous power or up to 20dBm peak power in a duty cycled operation.
147 | # Here we will always use PA_BOOST.
148 | # Since we use PA_BOOST, Pout = 2 + OutputPower and MaxPower could be any number (Why not 0b111/0x7?)
149 | PaSelect = {'PA_BOOST':0b1, 'RFO':0b0} # Choose PA_BOOST (instead of RFO) as the power amplifier
150 | MaxPower = {'15dBm':0x7, '13dBm':0x2} # Pmax = 10.8 + 0.6 * 7
151 | OutputPower = {'17dBm':0xf, '2dBm':0x0}
152 | self.spi_write('RegPaConfig', PaSelect['PA_BOOST'] << 7 | MaxPower['15dBm'] << 4 | OutputPower['2dBm'])
153 |
154 | # Enables the +20dBm option on PA_BOOST pin.
155 | if plus20dBm: # PA (Power Amplifier) DAC (Digital Analog Converter)
156 | PaDac = {'default':0x04, 'enable_PA_BOOST':0x07} # Can be 0x04 or 0x07. 0x07 will enables the +20dBm option on PA_BOOST pin
157 | self.spi_write('RegPaDac', PaDac['enable_PA_BOOST'])
158 |
159 | # FIFO data buffer
160 | # SX1276 has a 256 byte memory area as the FIFO buffer for Tx/Rx operations.
161 | # How do we know which area is for Tx and which is for Rx.
162 | # We must set the base addresses RegFifoTxBaseAddr and RegFifoRxBaseAddr independently.
163 | # Since SX1276 work in a half-duplex manner, we better set both base addresses
164 | # at the bottom (0x00) of the FIFO buffer so that we can buffer 256 byte data
165 | # during transmition or reception.
166 | self.Fifo_Bottom = 0x00 # We choose this value to max buffer we can write (then send out)
167 | self.spi_write('RegFifoTxBaseAddr', self.Fifo_Bottom)
168 | self.spi_write('RegFifoRxBaseAddr', self.Fifo_Bottom)
169 |
170 | #######################
171 | # #
172 | # 4. Interrupt #
173 | # #
174 | #######################
175 |
176 | # If configured, An TxDone IRQ is triggered transmittion finishes.
177 | # How to understand Table 18? When we want to set IRQ trigger, We use Table 18.
178 | # If we want RxDone triggers DIO0, we write 0b00 << 6 to RegDioMapping1. How we know it is 6? Because 6th and 7th bits are for DIO0.
179 | # Why 0b00 instead of 0b01? Because TxDone would trigger DIO0.
180 | # If we want FhssChangeChannel trigger DIO1, we write 0b01 << 4 to RegDioMapping1.
181 | # Why 0b01? See Table 18, col "DIO1", row "01"
182 | self.DioMapping = {
183 | 'Dio0' : {
184 | 'RxDone' : 0b00 << 6,
185 | 'TxDone' : 0b01 << 6,
186 | 'CadDone' : 0b10 << 6
187 | },
188 | 'Dio1' : {
189 | 'RxTimeout' : 0b00 << 4,
190 | 'FhssChangeChannel': 0b01 << 4,
191 | 'CadDetected' : 0b10 << 4
192 | },
193 | 'Dio2' : {
194 | 'FhssChangeChannel': 0b00 << 2,
195 | 'FhssChangeChannel': 0b01 << 2,
196 | 'FhssChangeChannel': 0b10 << 2
197 | },
198 | 'Dio3' : { },
199 | 'Dio4' : { },
200 | 'Dio5' : {
201 | 'ModeReady' : 0b00 << 4,
202 | },
203 | }
204 |
205 | self.DioMapping = {
206 | 'Tx' : self.DioMapping['Dio0']['TxDone'] | self.DioMapping['Dio1']['FhssChangeChannel'],
207 | 'Rx' : self.DioMapping['Dio0']['RxDone'] | self.DioMapping['Dio1']['FhssChangeChannel']
208 | }
209 |
210 | self.IrqFlags = {
211 | 'RxTimeout' : 0b1 << 7,
212 | 'RxDone' : 0b1 << 6,
213 | 'PayloadCrcError' : 0b1 << 5,
214 | 'ValidHeader' : 0b1 << 4,
215 | 'TxDone' : 0b1 << 3,
216 | 'CadDone' : 0b1 << 2,
217 | 'FhssChangeChannel': 0b1 << 1,
218 | 'CadDetected' : 0b1 << 0,
219 | }
220 |
221 | dio0_pin = Pin(DIO0_Pin, Pin.IN)
222 | dio0_pin.irq(handler=self._irq_handler, trigger=Pin.IRQ_RISING)
223 | dio1_pin = Pin(DIO1_Pin, Pin.IN)
224 | dio1_pin.irq(handler=self._irq_handler, trigger=Pin.IRQ_RISING)
225 | self.mode = 'STANDBY' # Request Standby mode so SX1276 performs reception initialization.
226 |
227 | def spi_write(self, reg, data, fifo=False):
228 | wb = bytes([self.RegTable[reg] | 0x80]) # Create a writing byte
229 | if fifo:
230 | data = wb + data
231 | else:
232 | data = wb + bytes([data])
233 | self.cs_pin.value(0) # Bring the CS pin low to enable communication
234 | self.spi.write(data)
235 | self.cs_pin.value(1) # release the bus.
236 |
237 | def spi_read(self, reg=None, length=None):
238 | self.cs_pin.value(0)
239 | # https://docs.micropython.org/en/latest/library/machine.SPI.html#machine-softspi
240 | if length is None:
241 | data = self.spi.read(2, self.RegTable[reg])[1]
242 | else:
243 | data = self.spi.read(length+1, self.RegTable[reg])[1:]
244 | self.cs_pin.value(1)
245 | return data
246 |
247 | def set_freq(self):
248 | FhssPresentChannel = self.spi_read('RegHopChannel') & 0b00_111_111
249 | Frf = int(self.FHSS_list[FhssPresentChannel] / self.FSTEP)
250 | #if self.debug: print('[New CH]', FhssPresentChannel)
251 | self.spi_write('RegFrfMsb', (Frf >> 16) & 0xff)
252 | self.spi_write('RegFrfMid', (Frf >> 8) & 0xff)
253 | self.spi_write('RegFrfLsb', Frf & 0xff)
254 |
255 | @property
256 | def mode(self):
257 | return self._mode
258 |
259 | @mode.setter
260 | def mode(self, value):
261 | #print('[New mode]', value)
262 | if value == 'TX':
263 | self.set_freq()
264 | self.spi_write('RegDioMapping1', self.DioMapping['Tx'])
265 | self.is_available = False
266 | elif value == 'RXCONTINUOUS':
267 | # Q: so why we use RXCONTINUOUS instead of RXSINGLE?
268 | # A: If you refers to page 39 of the datasheet, you will find RXSINGLE procedure has a Timeout mechanism.
269 | # It is an energy-saving measure. The receiver wakes up from sleep mode and listen the channel.
270 | # If it find nothing, it goes back to sleep.
271 | # When we do regular commu, our receive will listen the channel indefinitely until we stop it actively.
272 | self.set_freq()
273 | self.spi_write('RegDioMapping1', self.DioMapping['Rx'])
274 | self.is_available = False
275 | elif value == 'STANDBY':
276 | self.spi_write('RegDioMapping1', 0x00)
277 | else:
278 | print('[Error] Unknown working mode')
279 | if self.mode != value:
280 | self.spi_write('RegOpMode', self.Mode[value])
281 | self._mode = value
282 |
283 | def read_fifo(self):
284 | self.spi_write('RegFifoAddrPtr', self.spi_read('RegFifoRxCurrentAddr'))
285 | packet = self.spi_read('RegFifo', self.spi_read('RegRxNbBytes'))
286 | PacketSnr = self.spi_read('RegPktSnrValue')
287 | SNR = struct.unpack_from('b', bytes([PacketSnr]))[0] / 4
288 | PacketRssi = self.spi_read('RegPktRssiValue')
289 | #Rssi = read(RegRssiValue)
290 | if SNR < 0:
291 | RSSI = -157 + PacketRssi + SNR
292 | else:
293 | RSSI = -157 + 16 / 15 * PacketRssi
294 | RSSI = round(RSSI, 2) # Table 7 Frequency Synthesizer Specification
295 | return packet, SNR, RSSI
296 |
297 | def write_fifo(self, data):
298 | self.spi_write('RegFifoAddrPtr', self.Fifo_Bottom)
299 | self.spi_write('RegFifo', data, fifo=True) # Write Data FIFO
300 | self.spi_write('RegPayloadLength', len(data))
301 |
302 | def send(self, dst_id=0, pkt_id=0, pkt_type=0, msg='', retry=1, timeout=9, debug=False): # src_id, dst_id,
303 | if len(msg) > 240:
304 | # The message in the buffer object will be stored in FIFO register before it is sent out. While, the FIFO register is 256 byte in size and it cannot be overflowed.
305 | # In addition, this library is working in data link layer and it is upper layer's responsibility to do fragmentation (https://www.geeksforgeeks.org/fragmentation-network-layer/).
306 | print('You got the error because you are trying to send a very long message. You can find an explaination to this error in the code comment.')
307 | raise # cannot send a too large message
308 | # 1. Create header
309 | # 2. Put header and message together
310 | # 3. Write payload to FIFO
311 | # 4. Put the modem in Tx mode so payload is sent out
312 | # 5. Then put the modem in Rx mode and wait 15 seconds if the packet is asking receiver to acknowledge.
313 | # 6. Or wait no time if the packet is for broadcasting or is for acknowledging
314 | # [Tx side] self.pkt_type = req ; Mode = Tx ; TxDone; RxCont
315 | # [Rx side] RxDone ; Mode = STANDBY ; send 'ACK'
316 | self.pkt_type = pkt_type
317 | if pkt_type == self.PKT_TYPE['REQ']:
318 | pkt_id = urandom.randint(1,65535)
319 | self.pkt_id = pkt_id
320 | header = struct.pack(self.header_fmt, self.src_id, dst_id, pkt_id, pkt_type)
321 | data = header + msg.encode()
322 |
323 | if pkt_type == self.PKT_TYPE['REQ']:
324 | for _ in range(retry):
325 | self.mode = 'STANDBY'
326 | self.write_fifo(data)
327 | self.mode = 'TX' # Request Standby mode so SX1276 send out payload
328 | for _ in range(timeout):
329 | if self.pkt_id == 0:
330 | break
331 | time.sleep(1)
332 | else:
333 | if debug: print('[Debug] REQ is not ACKed before timeout is triggered') # No break means no response in 5 seconds
334 | if self.pkt_id == 0:
335 | break
336 | else:
337 | if debug: print('[Debug] Resend the REQ packet {} times but it is still not ACKed'.format(retry)) # No break means no response in 5 seconds
338 | elif pkt_type in [self.PKT_TYPE['ACK'], self.PKT_TYPE['BRD']]:
339 | self.mode = 'STANDBY'
340 | self.write_fifo(data)
341 | self.mode = 'TX'
342 | else:
343 | print("Unsupported Packet Type")
344 |
345 | def _irq_handler(self, pin):
346 | irq_flags = self.spi_read('RegIrqFlags')
347 | self.spi_write('RegIrqFlags', 0xff) # write 0xff could clear all types of interrupt pkt_type
348 | # For one complete "Request for acknowledgement" communication, there are 4 critical points (CP):
349 | # Step 0: The receiver is put in RxCont mode.
350 | # Step 1: The sender Tx something then IRQ TxDone is trigger on the sender. (1st critical point)
351 | # Step 2: In the irq handler of the sender, "mode shifts from Tx to RxCont" so the sender prepares to listen the ACK response (step 8).
352 | # Step 3: An IRQ RxDone is trigger on all receivers. (2nd CP)
353 | # Step 4: In the irq handler, if dst_id matches self.src_id, the receiver know it is the right recipient.
354 | # Step 5: The right receiver will shift mode to STANDBY before Tx the ACK.
355 | # Step 6: The receiver Tx the ACK then IRQ TxDone is trigger on the RECEIVER. (3rd CP)
356 | # Step 7: In the irq handler, the receiver will be put in STANDBY mode for further use.
357 | # Step 8: The sender catch the ACK response (see step 2) when IRQ RxDone is triggered on the sender. (4th CP)
358 | # Step 9: In the irq handler, the sender's mode is shifted from RxCont to STANDBY for further use. Done
359 | if irq_flags & self.IrqFlags['TxDone']:
360 | # When Tx mode is requested and data is send out, TxDone is triggered.
361 | if self.pkt_type == self.PKT_TYPE['REQ']:
362 | # Sender's REQ Tx will meet this condition
363 | # 1st critical point (CP), mode shifts from Tx to RxCont
364 | self.mode = 'RXCONTINUOUS'
365 | elif self.pkt_type == self.PKT_TYPE['ACK']:
366 | # 3rd CP: Receiver's ACK response will meet this condition
367 | # Since we are doing two-way communication, now the receiver should be freed.
368 | #self.mode = 'STANDBY'
369 | self.is_available = True # Free the receiver
370 | elif self.pkt_type == self.PKT_TYPE['BRD']:
371 | self.is_available = True # Free the sender after broadcasting
372 | self.after_TxDone(None)
373 |
374 | elif irq_flags & self.IrqFlags['RxDone']:
375 | packet, SNR, RSSI = self.read_fifo() # read fifo
376 | if irq_flags & self.IrqFlags['PayloadCrcError']:
377 | print('[PayloadCrcError]', packet)
378 | else:
379 | if len(packet) < self.header_size:
380 | print(packet, SNR, RSSI)
381 | return
382 | header, data = packet[:self.header_size], packet[self.header_size:] # extract header
383 | src_id, dst_id, pkt_id, pkt_type = struct.unpack(self.header_fmt, header) # parse header
384 | if self.debug: print('[Debug] Rx',pkt_type)
385 | if pkt_type == self.PKT_TYPE['REQ']: # REQ Received
386 | # Receiver will get a REQ packet from the sender and meet this condition
387 | if dst_id == self.src_id:
388 | # 2nd CP
389 | self.mode = 'STANDBY'
390 | self.send(dst_id=src_id, pkt_id=pkt_id, pkt_type=self.PKT_TYPE['ACK'], msg='') # This is an ack message
391 | #print("We received a REQ packet and its dst_id matches our src_id. We are going to acknowledge it.")
392 | self.req_packet_handler(None, data, SNR, RSSI)
393 | if self.debug: print("[RxDone] Right REQ receiver")
394 | else:
395 | #self.req_packet_handler(None, data, SNR, RSSI)
396 | # Shifting from 'RXCONTINUOUS' to 'RXCONTINUOUS' is not needed but we need reset IRQ
397 | self.mode = 'RXCONTINUOUS'
398 | if self.debug: print("[RxDone] Wrong REQ receiver") # We received a REQ packet but its dst_id does not match our src_id.
399 | # We are not going to acknowledge it but we still display its content.
400 | elif pkt_type == self.PKT_TYPE['ACK']: # ACK Received
401 | if pkt_id == self.pkt_id:
402 | # 4th CP: The right sender get an ACK packet from the receiver and meet this condition
403 | self.pkt_id = 0 # clear pkt_id so waiting in send function ends
404 | self.mode = 'STANDBY' # The sender has got the ACK packet so we shift way from RxCont mode.
405 | self.is_available = True # Free the sender
406 | if self.debug: print("[RxDone] Right ACK receiver") # REQ is ACKed
407 | else:
408 | #print("We are not the original sender although we have received an ACK response. Ignore it.")
409 | self.mode = 'RXCONTINUOUS'
410 | if self.debug: print("[RxDone] Wrong ACK receiver")
411 | elif pkt_type == self.PKT_TYPE['BRD']:
412 | # BRD Received by the receiver. Do nothing.
413 | self.brd_packet_handler(None, data, SNR, RSSI)
414 | #print("We received a BRD packet whose sender does not expect an acknowledgement.")
415 | self.mode = 'RXCONTINUOUS'
416 | if self.debug: print("[RxDone] BRD receiver")
417 | else:
418 | print('[Error]', packet, SNR, RSSI)
419 |
420 | elif irq_flags & self.IrqFlags['FhssChangeChannel']:
421 | self.set_freq()
422 | else:
423 | for i, j in self.IrqFlags.items():
424 | if irq_flags & j:
425 | print('[Sth went wrong]', i)
426 |
427 | def req_packet_handler(self, data, SNR, RSSI):
428 | pass
429 |
430 | def brd_packet_handler(self, data, SNR, RSSI):
431 | pass
432 |
433 | def after_TxDone(self, _):
434 | pass
435 |
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/misc/receiver.ipynb:
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1 | {
2 | "cells": [
3 | {
4 | "cell_type": "code",
5 | "execution_count": 1,
6 | "id": "0cfb6a30",
7 | "metadata": {},
8 | "outputs": [
9 | {
10 | "name": "stdout",
11 | "output_type": "stream",
12 | "text": [
13 | "\n",
14 | "WebREPL connected\n",
15 | ">>> \n",
16 | "6\n",
17 | "paste mode; Ctrl-C to cancel, Ctrl-D to finish\n",
18 | "=== from machine import Pin\n",
19 | "=== import time, urandom as random\n",
20 | "=== from lora import SX1276\n",
21 | "=== \n",
22 | "=== # Heltec WiFi LoRa 32 V2\n",
23 | "=== LoRa_MISO_Pin = 19\n",
24 | "=== LoRa_MOSI_Pin = 27\n",
25 | "=== LoRa_SCK_Pin = 5\n",
26 | "=== LoRa_CS_Pin = 18\n",
27 | "=== LoRa_RST_Pin = 14\n",
28 | "=== LoRa_DIO0_Pin = 26\n",
29 | "=== LoRa_DIO1_Pin = 35\n",
30 | "=== LoRa_DIO2_Pin = 34\n",
31 | "=== SPI_CH = 1\n",
32 | "=== \n",
33 | "=== random.seed(11)\n",
34 | "=== channels2Hopping = [914_000_000+200_000 * random.randint(0,10) for i in range(128)] # Both sender and receiver need to know the sequence of frequences they are hopping on before the first hopping operation.\n",
35 | "=== \n",
36 | "=== LoRa_id = 0\n",
37 | "=== lora = SX1276(LoRa_RST_Pin, LoRa_CS_Pin, SPI_CH, LoRa_SCK_Pin, LoRa_MOSI_Pin, LoRa_MISO_Pin,\n",
38 | "=== LoRa_DIO0_Pin, LoRa_DIO1_Pin, LoRa_id, channels2Hopping, debug=False)\n",
39 | "=== \n",
40 | "=== def get_payload(self, data, SNR, RSSI):\n",
41 | "=== global received_payload\n",
42 | "=== received_payload = data\n",
43 | "=== \n",
44 | "=== lora.req_packet_handler = get_payload\n",
45 | "=== lora.brd_packet_handler = lambda self, data, SNR, RSSI: print(\"[BRD]\", data)\n",
46 | "=== \n",
47 | "=== ###########################################\n",
48 | "=== # #\n",
49 | "=== # Prepare to receive first REQ packet #\n",
50 | "=== # #\n",
51 | "=== ###########################################\n",
52 | "=== \n",
53 | "=== received_payload = None\n",
54 | "=== lora.mode = 'RXCONTINUOUS'\n",
55 | "=== while not lora.is_available:\n",
56 | "=== time.sleep(1)\n",
57 | "=== print(\"[Note] We will see this line after receiver ACKed the first REQ packet\")\n",
58 | "=== \n",
59 | "=== ######################################################################\n",
60 | "=== # #\n",
61 | "=== # if we receive the hello packet correctly, we reply it with Hi. #\n",
62 | "=== # #\n",
63 | "=== ######################################################################\n",
64 | "=== # if we fail, nothing will go further\n",
65 | "=== print('[Received]', received_payload)\n",
66 | "=== if received_payload[-6:] != b'Hello~': raise\n",
67 | "=== \n",
68 | "=== payload = str(random.randint(100,65536))+\") Hi ~ I have received your hello\" \n",
69 | "=== lora.send(dst_id=1, msg=payload, pkt_type=lora.PKT_TYPE['REQ'])\n",
70 | "=== print('[Sending]', payload)\n",
71 | "=== while not lora.is_available: # Stop if our reply got acknowledged. \n",
72 | "=== time.sleep(1)\n",
73 | "=== \n",
74 | "=== ##########################################\n",
75 | "=== # #\n",
76 | "=== # Prepare to receive two BRD packets #\n",
77 | "=== # #\n",
78 | "=== ##########################################\n",
79 | "=== \n",
80 | "=== received_payload = None\n",
81 | "=== lora.mode = 'RXCONTINUOUS'\n",
82 | "=== \n",
83 | "=== while not lora.is_available:\n",
84 | "=== #print(\"waiting\")\n",
85 | "=== time.sleep(1)\n",
86 | "=== \n",
87 | "=== print(\"[Note] This line will not be reached because BRD is not two-way communication\")\n",
88 | "=== \n",
89 | "F[Note] We will see this line after receiver ACKed the first REQ packet\n",
90 | "[Received] b'15267) Hello~'\n",
91 | "[Sending] &15267) Hi ~ I have received your hello\n",
92 | "[BRD] b'28805) This long BRD packet will be received'\n",
93 | "[BRD] b'10231) This long BRD packet will also be received even though a wrong dst_id is specified. It is BRD, dst_id does not matter~'\n"
94 | ]
95 | }
96 | ],
97 | "source": [
98 | "webrepl_host_ip=\"192.168.xxx.142\"\n",
99 | "import sys\n",
100 | "sys.path.append(\"/home/a/pyWebREPL-1.2\") # https://github.com/xg590/pyWebREPL\n",
101 | "from pyWebREPL import WEBREPL\n",
102 | "\n",
103 | "webrepl = WEBREPL(host=webrepl_host_ip, password='123456')\n",
104 | "\n",
105 | "webrepl.send('''\n",
106 | "from machine import Pin\n",
107 | "import time, urandom as random\n",
108 | "from lora import SX1276\n",
109 | "\n",
110 | "# Heltec WiFi LoRa 32 V2\n",
111 | "LoRa_MISO_Pin = 19\n",
112 | "LoRa_MOSI_Pin = 27\n",
113 | "LoRa_SCK_Pin = 5\n",
114 | "LoRa_CS_Pin = 18\n",
115 | "LoRa_RST_Pin = 14\n",
116 | "LoRa_DIO0_Pin = 26\n",
117 | "LoRa_DIO1_Pin = 35\n",
118 | "LoRa_DIO2_Pin = 34\n",
119 | "SPI_CH = 1\n",
120 | "\n",
121 | "random.seed(11)\n",
122 | "channels2Hopping = [914_000_000+200_000 * random.randint(0,10) for i in range(128)] # Both sender and receiver need to know the sequence of frequences they are hopping on before the first hopping operation.\n",
123 | "\n",
124 | "LoRa_id = 0\n",
125 | "lora = SX1276(LoRa_RST_Pin, LoRa_CS_Pin, SPI_CH, LoRa_SCK_Pin, LoRa_MOSI_Pin, LoRa_MISO_Pin,\n",
126 | " LoRa_DIO0_Pin, LoRa_DIO1_Pin, LoRa_id, channels2Hopping, debug=False)\n",
127 | "\n",
128 | "def get_payload(self, data, SNR, RSSI):\n",
129 | " global received_payload\n",
130 | " received_payload = data\n",
131 | "\n",
132 | "lora.req_packet_handler = get_payload\n",
133 | "lora.brd_packet_handler = lambda self, data, SNR, RSSI: print(\"[BRD]\", data)\n",
134 | "\n",
135 | "###########################################\n",
136 | "# #\n",
137 | "# Prepare to receive first REQ packet #\n",
138 | "# #\n",
139 | "###########################################\n",
140 | "\n",
141 | "received_payload = None\n",
142 | "lora.mode = 'RXCONTINUOUS'\n",
143 | "while not lora.is_available:\n",
144 | " time.sleep(1)\n",
145 | "print(\"[Note] We will see this line after receiver ACKed the first REQ packet\")\n",
146 | "\n",
147 | "######################################################################\n",
148 | "# #\n",
149 | "# if we receive the hello packet correctly, we reply it with Hi. #\n",
150 | "# #\n",
151 | "######################################################################\n",
152 | "# if we fail, nothing will go further\n",
153 | "print('[Received]', received_payload)\n",
154 | "if received_payload[-6:] != b'Hello~': raise\n",
155 | "\n",
156 | "payload = str(random.randint(100,65536))+\") Hi ~ I have received your hello\" \n",
157 | "lora.send(dst_id=1, msg=payload, pkt_type=lora.PKT_TYPE['REQ'])\n",
158 | "print('[Sending]', payload)\n",
159 | "while not lora.is_available: # Stop if our reply got acknowledged. \n",
160 | " time.sleep(1)\n",
161 | "\n",
162 | "##########################################\n",
163 | "# #\n",
164 | "# Prepare to receive two BRD packets #\n",
165 | "# #\n",
166 | "##########################################\n",
167 | "\n",
168 | "received_payload = None\n",
169 | "lora.mode = 'RXCONTINUOUS'\n",
170 | "\n",
171 | "while not lora.is_available:\n",
172 | " #print(\"waiting\")\n",
173 | " time.sleep(1)\n",
174 | "\n",
175 | "print(\"[Note] This line will not be reached because BRD is not two-way communication\")\n",
176 | "''')\n",
177 | "print(webrepl.recv())\n",
178 | "webrepl.close()"
179 | ]
180 | }
181 | ],
182 | "metadata": {
183 | "kernelspec": {
184 | "display_name": "Python 3 (ipykernel)",
185 | "language": "python",
186 | "name": "python3"
187 | },
188 | "language_info": {
189 | "codemirror_mode": {
190 | "name": "ipython",
191 | "version": 3
192 | },
193 | "file_extension": ".py",
194 | "mimetype": "text/x-python",
195 | "name": "python",
196 | "nbconvert_exporter": "python",
197 | "pygments_lexer": "ipython3",
198 | "version": "3.10.6"
199 | }
200 | },
201 | "nbformat": 4,
202 | "nbformat_minor": 5
203 | }
204 |
--------------------------------------------------------------------------------
/misc/sender.ipynb:
--------------------------------------------------------------------------------
1 | {
2 | "cells": [
3 | {
4 | "cell_type": "code",
5 | "execution_count": 1,
6 | "id": "794f3696",
7 | "metadata": {},
8 | "outputs": [
9 | {
10 | "name": "stdout",
11 | "output_type": "stream",
12 | "text": [
13 | "\n",
14 | "WebREPL connected\n",
15 | ">>> \n",
16 | "6\n",
17 | "paste mode; Ctrl-C to cancel, Ctrl-D to finish\n",
18 | "=== from machine import Pin\n",
19 | "=== import time, urandom as random\n",
20 | "=== from lora import SX1276\n",
21 | "=== \n",
22 | "=== # Heltec WiFi LoRa 32 V2\n",
23 | "=== LoRa_MISO_Pin = 19\n",
24 | "=== LoRa_MOSI_Pin = 27\n",
25 | "=== LoRa_SCK_Pin = 5\n",
26 | "=== LoRa_CS_Pin = 18\n",
27 | "=== LoRa_RST_Pin = 14\n",
28 | "=== LoRa_DIO0_Pin = 26\n",
29 | "=== LoRa_DIO1_Pin = 35\n",
30 | "=== LoRa_DIO2_Pin = 34\n",
31 | "=== SPI_CH = 1\n",
32 | "=== \n",
33 | "=== random.seed(11)\n",
34 | "=== channels2Hopping = [914_000_000+200_000 * random.randint(0,10) for i in range(128)] # 914~916 MHz\n",
35 | "=== \n",
36 | "=== LoRa_id = 1\n",
37 | "=== lora = SX1276(LoRa_RST_Pin, LoRa_CS_Pin, SPI_CH, LoRa_SCK_Pin, LoRa_MOSI_Pin, LoRa_MISO_Pin,\n",
38 | "=== LoRa_DIO0_Pin, LoRa_DIO1_Pin, LoRa_id, channels2Hopping, debug=False)\n",
39 | "=== \n",
40 | "=== def get_payload(self, data, SNR, RSSI):\n",
41 | "=== global received_payload\n",
42 | "=== received_payload = data\n",
43 | "=== \n",
44 | "=== lora.req_packet_handler = get_payload\n",
45 | "=== \n",
46 | "=== ###########################################\n",
47 | "=== # #\n",
48 | "=== # First REQ packet #\n",
49 | "=== # #\n",
50 | "=== ###########################################\n",
51 | "=== \n",
52 | "=== payload = str(random.randint(100,65536))+\") Hello~\"\n",
53 | "=== print('[Sending]', payload)\n",
54 | "=== lora.send(dst_id=0, msg=payload, pkt_type=lora.PKT_TYPE['REQ']) # Sender's lora_id is 1 and receiver's is 0\n",
55 | "=== while not lora.is_available: time.sleep(1)\n",
56 | "=== \n",
57 | "=== #####################################################\n",
58 | "=== # #\n",
59 | "=== # Going to receive a Hi. Two way communication~ #\n",
60 | "=== # #\n",
61 | "=== #####################################################\n",
62 | "=== \n",
63 | "=== received_payload = None\n",
64 | "=== lora.mode = 'RXCONTINUOUS'\n",
65 | "=== \n",
66 | "=== while not lora.is_available: \n",
67 | "=== time.sleep(1)\n",
68 | "=== \n",
69 | "=== print('[Received] What we receive from the receiver is:', received_payload)\n",
70 | "=== \n",
71 | "=== #######################################################\n",
72 | "=== # #\n",
73 | "=== # Send a REQ packet but specify a wrong receiver #\n",
74 | "=== # #\n",
75 | "=== #######################################################\n",
76 | "=== \n",
77 | "=== payload = str(random.randint(100,65536))+\") You will not receive this packet because we specified a wrong dst_id\"\n",
78 | "=== print('[Sending]', payload)\n",
79 | "=== lora.send(dst_id=3, msg=payload, pkt_type=lora.PKT_TYPE['REQ']) \n",
80 | "=== \n",
81 | "=== for i in range(10):\n",
82 | "=== if lora.is_available: break\n",
83 | "=== time.sleep(1)\n",
84 | "=== else:\n",
85 | "=== print(\"[Note] you will see this line because lora.is_available is always false\")\n",
86 | "=== \n",
87 | "=== ############################\n",
88 | "=== # #\n",
89 | "=== # Send two BRD packets #\n",
90 | "=== # #\n",
91 | "=== ############################\n",
92 | "=== \n",
93 | "=== time.sleep(10)\n",
94 | "=== payload = str(random.randint(100,65536))+\") This long BRD packet will be received\" # Broadcast a large packet so many hops are generated~\n",
95 | "=== print('[Sending]', payload)\n",
96 | "=== lora.send(dst_id=0, msg=payload, pkt_type=lora.PKT_TYPE['BRD']) # A broadcast request. Do not expect respond. \n",
97 | "=== \n",
98 | "=== time.sleep(10)\n",
99 | "=== payload = str(random.randint(100,65536))+\") This long BRD packet will also be received even though a wrong dst_id is specified. It is BRD, dst_id does not matter~\" \n",
100 | "=== print('[Sending]', payload)\n",
101 | "=== lora.send(dst_id=3, msg=payload, pkt_type=lora.PKT_TYPE['BRD']) # A broadcast request. Do not expect respond.\n",
102 | "=== \n",
103 | "[Sending] \n",
104 | "15267) Hello~\n",
105 | "0[Received] What we receive from the receiver is: b'15267) Hi ~ I have received your hello'\n",
106 | "[Sending] K56627) You will not receive this packet because we specified a wrong dst_id\n",
107 | "G[Note] you will see this line because lora.is_available is always false\n",
108 | "[Sending] ,28805) This long BRD packet will be received\n",
109 | "[Sending] }10231) This long BRD packet will also be received even though a wrong dst_id is specified. It is BRD, dst_id does not matter~\n",
110 | ">>> \n"
111 | ]
112 | }
113 | ],
114 | "source": [
115 | "webrepl_host_ip=\"192.168.xxx.164\"\n",
116 | "import sys\n",
117 | "sys.path.append(\"/home/a/pyWebREPL-1.2\") # https://github.com/xg590/pyWebREPL\n",
118 | "from pyWebREPL import WEBREPL\n",
119 | "\n",
120 | "webrepl = WEBREPL(host=webrepl_host_ip, password='123456')\n",
121 | "webrepl.send('''\n",
122 | "from machine import Pin\n",
123 | "import time, urandom as random\n",
124 | "from lora import SX1276\n",
125 | "\n",
126 | "# Heltec WiFi LoRa 32 V2\n",
127 | "LoRa_MISO_Pin = 19\n",
128 | "LoRa_MOSI_Pin = 27\n",
129 | "LoRa_SCK_Pin = 5\n",
130 | "LoRa_CS_Pin = 18\n",
131 | "LoRa_RST_Pin = 14\n",
132 | "LoRa_DIO0_Pin = 26\n",
133 | "LoRa_DIO1_Pin = 35\n",
134 | "LoRa_DIO2_Pin = 34\n",
135 | "SPI_CH = 1\n",
136 | "\n",
137 | "random.seed(11)\n",
138 | "channels2Hopping = [914_000_000+200_000 * random.randint(0,10) for i in range(128)] # 914~916 MHz\n",
139 | "\n",
140 | "LoRa_id = 1\n",
141 | "lora = SX1276(LoRa_RST_Pin, LoRa_CS_Pin, SPI_CH, LoRa_SCK_Pin, LoRa_MOSI_Pin, LoRa_MISO_Pin,\n",
142 | " LoRa_DIO0_Pin, LoRa_DIO1_Pin, LoRa_id, channels2Hopping, debug=False)\n",
143 | "\n",
144 | "def get_payload(self, data, SNR, RSSI):\n",
145 | " global received_payload\n",
146 | " received_payload = data\n",
147 | "\n",
148 | "lora.req_packet_handler = get_payload\n",
149 | "\n",
150 | "###########################################\n",
151 | "# #\n",
152 | "# First REQ packet #\n",
153 | "# #\n",
154 | "###########################################\n",
155 | "\n",
156 | "payload = str(random.randint(100,65536))+\") Hello~\"\n",
157 | "print('[Sending]', payload)\n",
158 | "lora.send(dst_id=0, msg=payload, pkt_type=lora.PKT_TYPE['REQ']) # Sender's lora_id is 1 and receiver's is 0\n",
159 | "while not lora.is_available: time.sleep(1)\n",
160 | "\n",
161 | "#####################################################\n",
162 | "# #\n",
163 | "# Going to receive a Hi. Two way communication~ #\n",
164 | "# #\n",
165 | "#####################################################\n",
166 | "\n",
167 | "received_payload = None\n",
168 | "lora.mode = 'RXCONTINUOUS'\n",
169 | "\n",
170 | "while not lora.is_available: \n",
171 | " time.sleep(1)\n",
172 | "\n",
173 | "print('[Received] What we receive from the receiver is:', received_payload)\n",
174 | "\n",
175 | "#######################################################\n",
176 | "# #\n",
177 | "# Send a REQ packet but specify a wrong receiver #\n",
178 | "# #\n",
179 | "#######################################################\n",
180 | "\n",
181 | "payload = str(random.randint(100,65536))+\") You will not receive this packet because we specified a wrong dst_id\"\n",
182 | "print('[Sending]', payload)\n",
183 | "lora.send(dst_id=3, msg=payload, pkt_type=lora.PKT_TYPE['REQ']) \n",
184 | "\n",
185 | "for i in range(10):\n",
186 | " if lora.is_available: break\n",
187 | " time.sleep(1)\n",
188 | "else:\n",
189 | " print(\"[Note] you will see this line because lora.is_available is always false\")\n",
190 | "\n",
191 | "############################\n",
192 | "# #\n",
193 | "# Send two BRD packets #\n",
194 | "# #\n",
195 | "############################\n",
196 | "\n",
197 | "time.sleep(10)\n",
198 | "payload = str(random.randint(100,65536))+\") This long BRD packet will be received\" # Broadcast a large packet so many hops are generated~\n",
199 | "print('[Sending]', payload)\n",
200 | "lora.send(dst_id=0, msg=payload, pkt_type=lora.PKT_TYPE['BRD']) # A broadcast request. Do not expect respond. \n",
201 | "\n",
202 | "time.sleep(10)\n",
203 | "payload = str(random.randint(100,65536))+\") This long BRD packet will also be received even though a wrong dst_id is specified. It is BRD, dst_id does not matter~\" \n",
204 | "print('[Sending]', payload)\n",
205 | "lora.send(dst_id=3, msg=payload, pkt_type=lora.PKT_TYPE['BRD']) # A broadcast request. Do not expect respond.\n",
206 | " \n",
207 | "\n",
208 | "''')\n",
209 | "print(webrepl.recv())\n",
210 | "webrepl.close()"
211 | ]
212 | }
213 | ],
214 | "metadata": {
215 | "kernelspec": {
216 | "display_name": "Python 3 (ipykernel)",
217 | "language": "python",
218 | "name": "python3"
219 | },
220 | "language_info": {
221 | "codemirror_mode": {
222 | "name": "ipython",
223 | "version": 3
224 | },
225 | "file_extension": ".py",
226 | "mimetype": "text/x-python",
227 | "name": "python",
228 | "nbconvert_exporter": "python",
229 | "pygments_lexer": "ipython3",
230 | "version": "3.10.6"
231 | }
232 | },
233 | "nbformat": 4,
234 | "nbformat_minor": 5
235 | }
236 |
--------------------------------------------------------------------------------
/receiver/lora.py:
--------------------------------------------------------------------------------
1 | ../lora.py
--------------------------------------------------------------------------------
/receiver/receiver.py:
--------------------------------------------------------------------------------
1 | from machine import Pin
2 | import time, urandom as random
3 | from lora import SX1276
4 |
5 | # Heltec WiFi LoRa 32 V2
6 | LoRa_MISO_Pin = 19
7 | LoRa_MOSI_Pin = 27
8 | LoRa_SCK_Pin = 5
9 | LoRa_CS_Pin = 18
10 | LoRa_RST_Pin = 14
11 | LoRa_DIO0_Pin = 26
12 | LoRa_DIO1_Pin = 35
13 | LoRa_DIO2_Pin = 34
14 | SPI_CH = 1
15 |
16 | random.seed(11)
17 | channels2Hopping = [914_000_000+200_000 * random.randint(0,10) for i in range(128)] # Both sender and receiver need to know the sequence of frequences they are hopping on before the first hopping operation.
18 |
19 | LoRa_id = 0
20 | lora = SX1276(LoRa_RST_Pin, LoRa_CS_Pin, SPI_CH, LoRa_SCK_Pin, LoRa_MOSI_Pin, LoRa_MISO_Pin,
21 | LoRa_DIO0_Pin, LoRa_DIO1_Pin, LoRa_id, channels2Hopping, debug=False)
22 |
23 | def get_payload(self, data, SNR, RSSI):
24 | global received_payload
25 | received_payload = data
26 |
27 | lora.req_packet_handler = get_payload
28 | lora.brd_packet_handler = lambda self, data, SNR, RSSI: print("[BRD]", data)
29 |
30 | ###########################################
31 | # #
32 | # Prepare to receive first REQ packet #
33 | # #
34 | ###########################################
35 |
36 | received_payload = None
37 | lora.mode = 'RXCONTINUOUS'
38 | while not lora.is_available:
39 | time.sleep(1)
40 | print("[Note] We will see this line after receiver ACKed the first REQ packet with an ACK packet. And the receiver will stop listening, become a new sender, and send a REQ packet to the old sender (new receiver).")
41 |
42 | ######################################################################
43 | # #
44 | # if we receive the hello packet correctly, we reply it with Hi. #
45 | # #
46 | ######################################################################
47 | # if we fail, nothing will go further
48 | print('[Received]', received_payload)
49 | if received_payload[-6:] != b'Hello~': raise
50 |
51 | payload = str(random.randint(100,65536))+") Hi ~ I have received your hello"
52 | lora.send(dst_id=1, msg=payload, pkt_type=lora.PKT_TYPE['REQ'])
53 | print('[Sending]', payload)
54 | while not lora.is_available: # Stop if our reply got acknowledged.
55 | time.sleep(1)
56 |
57 | ##########################################
58 | # #
59 | # Prepare to receive two BRD packets #
60 | # #
61 | ##########################################
62 |
63 | received_payload = None
64 | lora.mode = 'RXCONTINUOUS'
65 |
66 | while not lora.is_available:
67 | #print("waiting")
68 | time.sleep(1)
69 |
70 | print("[Note] This line will not be reached because BRD is not two-way communication. The receiver will not stop listening")
--------------------------------------------------------------------------------
/sender/lora.py:
--------------------------------------------------------------------------------
1 | ../lora.py
--------------------------------------------------------------------------------
/sender/sender.py:
--------------------------------------------------------------------------------
1 | from machine import Pin
2 | import time, urandom as random
3 | from lora import SX1276
4 |
5 | # Heltec WiFi LoRa 32 V2
6 | LoRa_MISO_Pin = 19
7 | LoRa_MOSI_Pin = 27
8 | LoRa_SCK_Pin = 5
9 | LoRa_CS_Pin = 18
10 | LoRa_RST_Pin = 14
11 | LoRa_DIO0_Pin = 26
12 | LoRa_DIO1_Pin = 35
13 | LoRa_DIO2_Pin = 34
14 | SPI_CH = 1
15 |
16 | random.seed(11)
17 | channels2Hopping = [914_000_000+200_000 * random.randint(0,10) for i in range(128)] # 914~916 MHz
18 |
19 | LoRa_id = 1
20 | lora = SX1276(LoRa_RST_Pin, LoRa_CS_Pin, SPI_CH, LoRa_SCK_Pin, LoRa_MOSI_Pin, LoRa_MISO_Pin,
21 | LoRa_DIO0_Pin, LoRa_DIO1_Pin, LoRa_id, channels2Hopping, debug=False)
22 |
23 | def get_payload(self, data, SNR, RSSI):
24 | global received_payload
25 | received_payload = data
26 |
27 | lora.req_packet_handler = get_payload
28 |
29 | ###########################################
30 | # #
31 | # First REQ packet #
32 | # #
33 | ###########################################
34 |
35 | payload = str(random.randint(100,65536))+") Hello~"
36 | print('[Sending]', payload)
37 | lora.send(dst_id=0, msg=payload, pkt_type=lora.PKT_TYPE['REQ']) # Sender's lora_id is 1 and receiver's is 0
38 | while not lora.is_available: time.sleep(1)
39 |
40 | #####################################################
41 | # #
42 | # Going to receive a Hi. Two way communication~ #
43 | # #
44 | #####################################################
45 |
46 | received_payload = None
47 | lora.mode = 'RXCONTINUOUS'
48 |
49 | while not lora.is_available:
50 | time.sleep(1)
51 |
52 | print('[Received] What we receive from the receiver is:', received_payload)
53 |
54 | #######################################################
55 | # #
56 | # Send a REQ packet but specify a wrong receiver #
57 | # #
58 | #######################################################
59 |
60 | payload = str(random.randint(100,65536))+") You will not receive this packet because we specified a wrong dst_id"
61 | print('[Sending]', payload)
62 | lora.send(dst_id=3, msg=payload, pkt_type=lora.PKT_TYPE['REQ'], timeout=10, retry=3, debug=True)
63 |
64 | for i in range(10):
65 | if lora.is_available: break
66 | time.sleep(1)
67 | else:
68 | print("[Note] you will see this line because lora.is_available is always false")
69 |
70 | ############################
71 | # #
72 | # Send two BRD packets #
73 | # #
74 | ############################
75 |
76 | time.sleep(10)
77 | payload = str(random.randint(100,65536))+") This long BRD packet will be received" # Broadcast a large packet so many hops are generated~
78 | print('[Sending]', payload)
79 | lora.send(dst_id=0, msg=payload, pkt_type=lora.PKT_TYPE['BRD']) # A broadcast request. Do not expect respond.
80 |
81 | time.sleep(10)
82 | payload = str(random.randint(100,65536))+") This long BRD packet will also be received even though a wrong dst_id is specified. It is BRD, dst_id does not matter~"
83 | print('[Sending]', payload)
84 | lora.send(dst_id=3, msg=payload, pkt_type=lora.PKT_TYPE['BRD']) # A broadcast request. Do not expect respond.
85 |
--------------------------------------------------------------------------------