RAK4200 / RAK4270 low level development

I’ve had a client working on a RAK4200 application who wants to try the low level development option rather than RUI.

Do you have a sample project for this & the RAK4270 which can use the boot loader?

If not using the bootloader, do you have one that just programs the whole device?

They are a bit concerned that the RAK4200 is no longer available in the store - what is the expected lifespan of the RAK4270?

If they get started with the RAK4200’s they have, how portable to the RAK4270 will it be.

I’d figure this all out myself but I’m up to my eyeballs with the TTN v2 to v3 migration and I can’t afford to mess it up for this client.


Hello Nick,
The RAK4200 is not listed in the store anymore, but if your customer is buying larger volumes he can contact our sales team directly.

We have no examples for the low level development for the RAK4270. I just looked though our private repositories, but there is nothing as well.

Instead we just updated the RUI code examples with new examples including the RAK4270. That might make it easier for your customer to consider RUI instead.

Compatibility RAK4200 to RAK4270

  • same MCU (STM32L071)
  • 98% pin compatible 2 pin are used different, 1 pin not available for user app)
  • different LoRa transceiver. The RAK4200 uses SX127x, the RAK4270 uses the newer SX126x


  • same MCU core
  • different LoRaWAN radio driver required
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Wow, lots of new examples to dig through - brilliant.

Thanks for confirming the pin differences which were as I suspected, the PCB should work with either.

They tried RUI previously - the round trip time is a real productivity destroyer. I spent hours trying to write a wrapper to enable some local development and do test compiles but then the whole system changed and the project was put on pause.

I’ll try some of the examples and see if I can get that local validation going again.

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Indeed, online compilers are great for getting people started when new to a technology.

But professional usage absolutely requires the ability to build locally based on fully archived dependencies.

It’s unfortunate that there’s no out-of-box starting point. Probably it wouldn’t be a great hurdle to port the Semtech code or its ST derivative that already understands the new radio, but it is an added step that wouldn’t be necessary if the vendor would provide an already ported starting point repository.

What is the use of the ANT_SW output in RAK4270?

Hello x893,

The ANT_SW signal is an internal signal of the module to control the RF antenna switch. It should NOT be connected.