Getting started with ST Murata LoRaWan board

ST Micro-Electronics is providing a development board with a Murata CMWX1ZZABZ-091 chip. This device is a module containing a STM32L0 chip (192Kb of Flash / 20Kb of RAM) associated with a Semtech SX1276 radio chip. This module can be used as a SoC for developing LoRaWan IoT devices. The Semtech chip is also capable of Sigfox. This module is a bit expensive but it is actually the one allowing LoRaWan and Sigfox communication in any of the RCZ zones.

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Send Sigfox messages with STM32 + S2LP

STM32 solution for using Sigfox is actually one of the best offer on the market has the solution is powerful, low consumption and allows global coverage with the use of the last Sigfox library versions including Monarq, Bubble… Different module providers are actually designing solutions based on this platform.

In this post we are going to see how to configure the STM32 platform, starting from a STM32L053 devkit plus a S2LP extension. Using a eclipse/gcc environment. The environment installation is described in this post about installing Eclipse for STM32.

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STM32 and Low Power Mode

STM32 ARM MCU are proposing different low power mode for saving energy when running IoT on battery. Some basic example of low power are delivered with the SDK as part of CubeMx solution but these example are not really complete, not well documented and in my point of view difficult to use in a Fresh new project. Basically my current feeling with STM32 is these guy are pretty good to write thesis on how to do magic stuff with the MCU, writing hundreds of pdf pages about really detailed stuff but they are really bad for providing some line of code to illustrate this valuable content with something practicable you can use on the go. So after spending a week working on a working and understood example of low power code, I’ll share with you the result of this work…

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STM32 and Arduino, working with a custom board

Arduino is supporting STM32 platform and after following the installation steps, you can easily work with the st-microelectronics development kit.

In the real life you need to create a specific setup once your prototype is transformed into a custom board. This setup redefines the pin mapping, the target MCU and needs to refine the firmware transfer method as you will use and external STLINK programmer.

In this post we are going to see the different step for doing this.

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Arduino for STM32

In a previous post I explained how to getting started with STM32 with classical Eclipse or Keil environments. These environments are very cool for starting from scratch in designing firmware. That said, you have to recreate a lot of basic functions and libraries to create your firmware.

On the other hand, the Arduino community is proposing a lot a existing libraries and a development framework with a large number of supported features. The STM32 community looks active and that’s a good way to quickly create advanced firmware.

That said there is different point blocking in my point of view for using Arduino as a professional environment:

  • Outside of the core libs and some nice one, most of the lib are badly written
  • The official editor is a mess if you manage more than 3 files…
  • Writing libraries with official editor is… “impossible”

For this reason, in this tuto, I’ll use Visual Code Studio  to see if the 2 last point can be solved. Regarding the first point, there is nothing better than using well coded libraries and rewrite (and share) the badly written one.

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Getting started with Nucleo32 – STM32L031

I have this board in my stock since some months and never taken time to play with it. As I’m starting some developments with STM32 it’s time to do it. I’ve tried to do some stuff using it at reception but even if there is some kind of Arduino mentions on the package the start is not as easy as on Arduino. Not regarding coding (it is more complicated but it is not the problem) but regarding the development environment. You need to use different tools and find yourself the way to use each of them. In my point of view ST would do a good thing simplify all this stuff. So in this post I’ll describe how to get started by creating your first led blink project. Hope it will save your time.

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The impact of putting an antenna in a box

IoT design a usually a matter of antenna as already seen in different previous blog post. Antenna performance is the assurance of your capacity to deploy your object in larger zone and a way to save energy by reducing transmission power.

As we will see, if you get a hardware component and simply put it in a box its radio behavior will be totally different as the box is impacting the transmission.

This post will practically show you the impact of a box on a device radio quality.

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miniVNA Tiny Plus review

I’ve got my miniVNA Tiny+ this summer and start making test with it. A VNA is a Vector Network Analyzer. Behind this dark name, this is a tool able to analyze the radio response of your circuit and ensure your circuit is tuned to the right frequency. From the data measured by this tool you can find the right adaptation circuit to match your central frequency.

For more information about RF circuit matching, you can read this other post.

The miniVNA Tiny+ is a low cost VNA solution less than 300€ covering frequencies from 1MHz to 3Ghz. These frequencies are good for most of IoT need : LPWAN around 868MHz and Bluetooth at 2,4GHz. The steps are 10Hz for a large precision. With two ports you can measure S11 – power transmitted and received over the same port – and S21 – power transmitted from port 1 and received over port 2.

The miniVNA Tiny+ is an usb solution working with a computer connected to and a software running on the computer. The software is based on Java and may support different Operating Systems.

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