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Lup Yuen Lee 李立源

The Medium Access Control Layer (right) of our Driver implements the LoRaWAN Protocol: Encryption, Receive Window, Duty Cycle, ... It exposes the MCPS Messaging Interface (IEEE 802.15.4) to the Node Layer (centre) via an Event Queue

github.com/lupyuen/bl_iot_sdk/

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Lup Yuen Lee 李立源

The Protocol is explained in this thread: Encryption, Receive Window, Duty Cycle, ...

qoto.org/@lupyuen/105874847933

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Lup Yuen Lee 李立源

How shall we implement the Event Queue for the Medium Access Control Layer? With the NimBLE Porting Layer of course!

lupyuen.github.io/articles/lor

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Lup Yuen Lee 李立源

Curiously, our Driver includes a Command-Line Interface (bottom) that Transmits and Receives LoRa Packets ... Directly calling the SX1276 Driver 🤔

github.com/lupyuen/bl_iot_sdk/

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Lup Yuen Lee 李立源

Uh-oh our Driver (from Mynewt) passes LoRaWAN Packets in Mbuf Format ... Let's find something equivalent on BL602 🤔

github.com/lupyuen/bl_iot_sdk/

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Lup Yuen Lee 李立源

What's an Mbuf? Why is it used by our Driver? Mbufs are Chains of Fixed-Size Blocks ... Works great with little RAM (no fragmentation) ... Created for BSD Unix in 1983!

mynewt.apache.org/latest/os/co

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Lup Yuen Lee 李立源

IoT SDK has a "pbuf" in the lwIP Lightweight TCP/IP Stack ... Maybe our BL602 Driver can use this instead of Mbuf? 🤔

github.com/lupyuen/bl_iot_sdk/

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Lup Yuen Lee 李立源

Here's a friendly doc by STMicro that explains MCPS Messaging in our Driver

st.com/content/ccc/resource/te

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Lup Yuen Lee 李立源

...Which explains why so many folks at STMicro are now reading this Thread

😉

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Lup Yuen Lee 李立源

Yep "pbuf" from the Lightweight IP Stack can be used instead of Mbuf ... We just need to shift the Header / Payload Pointer to work on Packets

github.com/lupyuen/bl_iot_sdk/

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Lup Yuen Lee 李立源

We verify that "pbuf" Packet Buffers can handle a full Packet ... Header: 20 bytes, Max Payload: 255 bytes

github.com/lupyuen/bl_iot_sdk/

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Lup Yuen Lee 李立源

Why "pbuf" is OK for handling Packets

github.com/lupyuen/bl_iot_sdk/

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Lup Yuen Lee 李立源

Our Driver uses Mbuf Queues (from Mynewt OS) ... We shall convert them to pbuf Event Queues ... From the NimBLE Porting Library

github.com/lupyuen/bl_iot_sdk/

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Lup Yuen Lee 李立源

Porting pbuf Packet Buffer Queue from Mynewt OS to ... Makes me hungry for Peanut Butter Jelly Sandwich 🤤

github.com/lupyuen/bl_iot_sdk/

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Lup Yuen Lee 李立源

Using this simpler Windows CMD script to build the Driver ... Quicker for fixing build errors

github.com/lupyuen/bl_iot_sdk/

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Lup Yuen Lee 李立源

Add the "c_cpp_properties.json" file to ... So that our Build Errors are highlighted

github.com/lupyuen/bl_iot_sdk/

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Lup Yuen Lee 李立源

Reference Implementation of Semtech Stack is here ... Includes drivers for SX1262 and SX1276

github.com/Lora-net/LoRaMac-no

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Lup Yuen Lee 李立源

Bought the RAKwireless Gateway: Developer D4H ... Will benchmark this with LoRa Gateway (Also based on RAKwireless RAK2287)

docs.rakwireless.com/Product-C

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Lup Yuen Lee 李立源

ChirpStack (open source server) is preinstalled on @RAKwireless ... We shall test this with and

docs.rakwireless.com/Product-C

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Lup Yuen Lee 李立源

on RAKwireless can generate random Application Keys for Over-The-Air Activation (OTAA) ... We shall use keys to activate our and devices wirelessly

thethingsindustries.com/docs/d

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Lup Yuen Lee 李立源

Our RAKwireless Gateway has received over 800 Packets in a day ... And I haven't powered on my BL602 and WisBlock gadgets yet! 🤔

docs.rakwireless.com/Product-C

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Lup Yuen Lee 李立源

Something (or Someone) is transmitting Packets every minute ... Signal Strength (RSSI) shows that they're a few hundred metres away

gist.github.com/lupyuen/8dacf0

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Lup Yuen Lee 李立源

Based on earlier Coverage Testing (with and ) ... High chance that our Mystery Transmitter is at the nearby Subway Station 🤔

lupyuen.github.io/articles/wis

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Lup Yuen Lee 李立源

Someday I might walk around with RAKwireless to find the Mystery Transmitter ... But for now let's test WisGate with WisBlock and BL602!

docs.rakwireless.com/Product-C

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Lup Yuen Lee 李立源

Still fixing Driver for ... So let's test WisGate with WisBlock first

github.com/lupyuen/bl_iot_sdk/

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Lup Yuen Lee 李立源

Driver for ... One last build error

github.com/lupyuen/bl_iot_sdk/

1
Lup Yuen Lee 李立源

Driver for ... Builds and links OK yay! 🎉 Heading out for second dose of Moderna ... And some downtime

github.com/lupyuen/bl_iot_sdk/

1
Lup Yuen Lee 李立源

Let's test RAKwireless with ... With this program ... Once I get home from vaccination

github.com/RAKWireless/WisBloc

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Lup Yuen Lee 李立源

sample fails to compile ... Let's find out why 🤔 (Hope it's not because of the vaccination)

github.com/lupyuen/wisblock-lo

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Lup Yuen Lee 李立源

sample now builds OK ... After upgrading SX126x Arduino Library to Version 2 ... Released 2 weeks ago!

github.com/lupyuen/wisblock-lo

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Lup Yuen Lee 李立源

We copy the Device EUI and Application Key from to the client ... For Over-The-Air Activation (OTAA)

github.com/lupyuen/wisblock-lo

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Lup Yuen Lee 李立源

joins the Network ... And gets accepted!

github.com/lupyuen/wisblock-lo

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Lup Yuen Lee 李立源

After joining 's Network wirelessly ... can now transmit LoRaWAN Packets to the LoRaWAN App

github.com/lupyuen/wisblock-lo

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Lup Yuen Lee 李立源

What's inside the Packet received by ? Check the Device Data ... "Hello!"

github.com/lupyuen/wisblock-lo

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Lup Yuen Lee 李立源

Inside the Join Network Request (Over-The-Air Activation) ... Received by from

github.com/lupyuen/wisblock-lo

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Lup Yuen Lee 李立源

After transmitting a packet, a Device () will open a short "Receive Window" ... To receive a Response Packet (if any) from the LoRaWAN Gateway ()

github.com/lupyuen/wisblock-lo

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Lup Yuen Lee 李立源

Receive Windows are explained in the LoRaWAN Specs

lora-alliance.org/resource_hub

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Lup Yuen Lee 李立源

Will @PINE64 (with Pine64 RFM90 LoRa Module) ... Talk to RAKwireless Gateway? Let's find out!

github.com/lupyuen/bl_iot_sdk/

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Lup Yuen Lee 李立源

These are the Commands ... Ported from Apache Mynewt OS

github.com/lupyuen/bl_iot_sdk/

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Lup Yuen Lee 李立源
Follow

tries to join the Network ... But no Join Request gets transmitted to WisGate 🤔

github.com/lupyuen/bl_iot_sdk/

· · Tusky · 1 · 2 · 1
Lup Yuen Lee 李立源

tries to send Join Network Request ... But hangs while hunting for the next LoRa Frequency Channel to transmit 🤔

github.com/lupyuen/bl_iot_sdk/

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Lup Yuen Lee 李立源

When hunts for the next Frequency Channel to transmit (Spread Spectrum) ... It listens to the airwaves to check whether the channel is in use ... Let's find out whether BL602 is doing Carrier Sensing correctly 🤔

github.com/lupyuen/bl_iot_sdk/

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Lup Yuen Lee 李立源

Oops Mynewt's Carrier Sensing implementation is outdated ... Semtech's LoRaWAN Reference Implementation does NOT require Carrier Sensing outside Japan and South Korea ... So we disable Carrier Sensing and use a random LoRa Frequency Channel

github.com/lupyuen/bl_iot_sdk/

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Lup Yuen Lee 李立源

After disabling Carrier Sensing ... hits an Exception while transmitting the Join Network Request ... Let's lookup these addresses in the RISC-V Disassembly

github.com/lupyuen/bl_iot_sdk/

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Lup Yuen Lee 李立源

According to our RISC-V Disassembly, Driver hits a Null Pointer Exception here ... Seems like non-essential logging code ... So let's disable this code

github.com/lupyuen/bl_iot_sdk/

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Lup Yuen Lee 李立源

is now transmitting the Join Network Request ... But doesn't receive any response from our LoRaWAN Gateway (WisGate) ... Let's check the WisGate LoRaWAN Log

github.com/lupyuen/bl_iot_sdk/

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Lup Yuen Lee 李立源

you're so funny ... I'm nowhere near Chinese Garden, Japanese Garden and Jurong Bird Park 😂

docs.rakwireless.com/Product-C

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Lup Yuen Lee 李立源

Let's move (and Pro @PINE64
) real close to RAKwireless ... For our testing

github.com/lupyuen/bl_iot_sdk/

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Lup Yuen Lee 李立源

Sadly our Gateway didn't receive any LoRaWAN Packets transmitted by ... Let's look inside the transmitted packets ... And verify the transmission with Airspy SDR

github.com/lupyuen/bl_iot_sdk/

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Lup Yuen Lee 李立源

Airspy SDR verifies that is indeed transmitting the Join Network packet ... Maybe it contains garbage 🤔

github.com/lupyuen/bl_iot_sdk/

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Lup Yuen Lee 李立源

Here's the "Join Network" Chirp ... Recorded by Airspy SDR with CubicSDR

youtu.be/7a4rfaI_zV4

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Lup Yuen Lee 李立源

Here's the "Join Network" Packet transmitted by ... Does this look right? 🤔 Let's compare with WisBlock

github.com/lupyuen/bl_iot_sdk/

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Lup Yuen Lee 李立源

"Join Network" Packet transmitted by ... Looks similar to the one transmitted by BL602 ... Nonce and Message Integrity Code will differ of course

github.com/lupyuen/wisblock-lo

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Lup Yuen Lee 李立源

Here are the Packets transmitted by RAKwireless ... Captured by Airspy SDR and CubicSDR

youtu.be/xdyi6XCo8Z8

1
Lup Yuen Lee 李立源

Packet: vs ... Seems BL602 is transmitting at Lower Power than WisBlock ... Let's check the Power Amplifier settings 🤔

github.com/lupyuen/bl_iot_sdk/

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Lup Yuen Lee 李立源

vs : Join Network Request ... Let's check the Nonce and Message Integrity Code ... Wonder if we can retransmit the BL602 packet from WisBlock 🤔

github.com/lupyuen/bl_iot_sdk/

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Lup Yuen Lee 李立源

Let's copy the Join Network Request generated by ... And retransmit with ... Surprise: the Join Request succeeds! 😲 Which proves the Nonce and Message Integrity Code are OK ... Probably the BL602 Power Amplifier setting is wrong 🤔

github.com/lupyuen/bl_iot_sdk/

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Lup Yuen Lee 李立源

But wait: Will allow replayed "Join Network" Requests? 😲 Nope it doesn't! will reject Replayed Requests because the Nonce needs to be unique ... Here's how we find Nonce Errors in RAKwireless WisGate

github.com/lupyuen/bl_iot_sdk/

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Lup Yuen Lee 李立源

For Reference: Here's how I connected @PINE64 to Pine64 RFM90 Module (SX1262)

github.com/lupyuen/bl_iot_sdk/

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@lupyuen
You rock Prof. If You needed adopting clang or fixing that 1bytedma transfers i got some spare resources.

0
Sir Funk 🇦🇺

@lupyuen how on earth do you keep a list of used nonces sensibly?

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📡(RTP) Privacy & Tech Tips

@lupyuen
Pretty capture :ablobcatrave:

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