MQTT is a lightweight and broadly used internet protocol (see “MQTT with lwip and NXP FRDM-K64F Board“). And probably the majority of IoT applications today are using Mosquitto as server (or ‘broker’ in MQTT language). By default, Mosquitto is using a protocol without encryption. In “Introduction to Security and TLS (Transport Layer Security)” I have covered the basics and needs for encryption. This article is about how to enable Mosquitto and clients to use the TLS protocol.
The Eclipse CDT build system automatically scans the files in my project folders and adds them to the list of files to be built. That works great if files are added through Eclipse and its plugins: That way Eclipse is notified and aware, and has the files added. But what if I have added files externally (outside of Eclipse)? how can I make Eclipse aware of it?
Many of my currently active projects are using Kinetis Design Studio (KDS) V3.2.0 from NXP (I have published many of my projects on GitHub). Now with the advent of the MCUXpresso IDE (see “MCUXpresso IDE: Unified Eclipse IDE for NXPs ARM Cortex-M Microcontrollers“), I have migrated several projects from KDS to MCUXpresso. This post is about how to easily get KDS projects ported and running in MCUXpresso IDE.
One great thing with Eclipse compared to proprietary IDEs are the thousands of available plugins. Yes, not every plugin is probably on the ‘must have’ list (I have listed some in a series starting with “5 Best Eclipse Plugins: #1 (Eclox with Doxygen, Graphviz and Mscgen)“).
The ‘traditional’ approach to install Eclipse plugins is using the menu Help > Install New Software. Using that approach, I have to use or enter an Eclipse update site. An easier way is to use the Eclipse Marketplace plugin which allows me to search and browse for plugins and simplifies installation of it. But as this one does not come installed by default with MCUXpresso. But it is my preferred way to browse and install plugins into Eclipse:
This is another article about the NXP MCUXpresso IDE (see “MCUXPresso IDE: Unified Eclipse IDE for NXPs ARM Cortex-M Microcontrollers“), this time it is about Post-build steps. Post-build steps are custom actions which can be executed after the build (or link phase), and are typically used to generate S-Record, Binary or Intel Hex files (see “S-Record, Intel Hex and Binary Files“).
To me, software and tools are by far more important than the microcontroller. Because the silicon is a ‘one time kind of thing’, where the software has to be maintained and working over a longer time. And at least my software usually needs to be ported to a new device, so portability and available software and tools are critical to me.
The combination of MCUXpresso SDK (formerly Kinetis SDK) and Processor Expert is unfortunately not supported by NXP. But I have found a way to get them work together in a nice way, and this article is about making that combination possible :-).
With debugging FreeRTOS applications in Eclipse, it is a big to have views available showing all the threads, queues, timers and heap memory allocation. One of the best Eclipse plugins are the one NXP provides for FreeRTOS: they are free of charge and give me pretty much everything I need. However, if you are not that familiar with FreeRTOS itself, here are a few tips to get more out of the plugins.
Instead creating a new project from scratch, often it is simpler to copy an existing Eclipse CDT project, then change it and go on. To copy-past the a project in Eclipse:
- Select the project in the Project Explorer View (CTRL-C on Windows)
- Then paste it in the Project Explorer View (CTRL-V on Windows), and I can specify the new name:
However, to make that process simpler, a few things have to be done right in the ‘source’ project first.
For a CubeSat project we only have a single board available. But multiple universities and developers need to have access to that board for developing and debugging the firmware. We cannot easily ship around the board: that takes a lot of time and during shipment nobody can use the board.
There is a nice feature in the Segger J-Link software which allows to share the debug connection over the network: the J-Link Remote Server. It even works nicely between different networks without complicated firewall setup:
When working and debugging a bootloader, debugging can be a challenge: During debugging the bootloader, a new binary gets loaded into the microcontroller address space which is unknown to the debugger. As soon as I step into the newly loaded binary, I only see assembly code, with that ugly “No source available” in Eclipse:
But wait: GDB is able to do pretty much everything you can imagine, so here is how to debug multiple binaries with GDB and Eclipse, and to turn the above into something which is easy to debug:
One of the biggest road blocks (beside of closed source) using the BLE (Bluetooth Low Energy) stack from NXP is that it requires expensive tools to compile and build the stack. The good news is that I have now the NXP BLE stack for the Mikroelektronika Hexiwear ported to Eclipse and GNU gcc build tools for ARM 🙂
Now I can use the data on the Hexiwear over BLE with the gatttool (see “Tutorial: Hexiwear Bluetooth Low Energy Packet Sniffing with Wireshark” and “Tutorial: BLE Pairing the Raspberry Pi 3 Model B with Hexiwear“). This article is taking things a step further and uses a Python script on Linux to access the sensor data on the BLE device:
The Achilles Heel of the Mikroelektronika Hexiwear is its charging: the charging and USB connector are only designed for a limited number of plug-unplug cycles, and it does not have a wireless charging capability like the Apple iWatch. Until now! I have built a DIY wireless charging system for the Hexiwear 🙂 :
For a university reasearch project I try to pair the Raspberry Pi 3 with a Mikroelektronika Hexiwear using BLE (Bluetooth Low Energy). Most of things worked after a lot of trial and error, but at a certain point I was stuck trying to write to send data from the Raspy to the BLE device.The Hexiwear BLE protocol description is very thin, so I ended up using a BLE sniffer to reverse engineer the protocol with Wireshark.
I’m using the NXP FRDM-K64F board in several projects: it is reasonably prices, has USB, Ethernet, micro SD card socket and connectors for Bluetooth classic and Nordic Semiconductor nRF24L01+ 2.4 GHz transceiver:
But one issue I have faced several times is that the board works fine while debugging and connected and powered by a host machine, but does not startup sometimes if powered by a battery or started without a debugger attached. I have found that the EzPort on the microcontroller is causing startup issues.
The Hexiwear (see “Hexiwear: Teardown of the Hackable ‘Do-Anything’ Device“) is a small and portable sensor node with built-in BLE (Bluetooth Low Energy) transceiver. In a research project we try to use multiple Hexiwear in a classroom environment and to collect sensor data on a Raspberry Pi. The Raspberry Pi 3 Model B running Linux has an on-board BLE transceiver too, so why not binding them (wirelessly) together?
Well, things seemed easy at the beginning, and as always, there are many things to learn on a journey like this…