The Espressif ESP32 devices are getting everywhere: they are inexpensive, readily available and Espressif IDF environment and build system actually is pretty good and working well for me including Eclipse (see “Building and Flashing ESP32 Applications with Eclipse“). The default way to program an ESP32 is to a) enter UART bootloader by pressing some push buttons and b) flash the application with ESP-IDF using a USB cable.
That works fine if the ESP32 is directly connected to the host PC. But in my case it is is behind an NXP Kinetis K22FX512 ARM Cortex-M4F microcontroller and not directly accessible by the host PC. So I had to find a way how to allow boot loading the ESP32 through the ARM Cortex-M which is the topic of this article.
The new semester is approaching in a very fast way, and so is the new lecture and lab module ‘Advanced Distributed Systems’ at the Lucerne University. For that module we are going to build a new ‘Sumo’ style robot with WLAN capabilities using the ESP32 chip. It will be a new robot PCB, and below is the current robot (based on NXP K22FX512) with the WLAN module connected to it:
It is great if vendors provide a starting point for my own projects. A working ‘blinky’ is always a great starter. Convenience always has a price, and with a ‘blinky’ it is that the code size for just ‘toggling a GPIO pin’ is exaggerated. For a device with a tiny amount of RAM and FLASH this can be concerning: will my application ever fit to that device if a ‘blinky’ takes that much? Don’t worry: a blinky (or any other project) can be easily trimmed down.
Binky on NXP LPC845-BRK Board
I use a ‘blinky’ project here just as an example: the trimming tips can apply to any other kind of projects too.
With the cost of an single pin, many ARM Cortex-M boards including the NXP i.MX RT1064 can produde SWO data: think about a pin able to stream data out of the chip in realtime. For example interrupt activity which otherwise might be hard to capture:
In a modern development workflow both command-line and a graphical user interface has its place. On the GUI side, Eclipse is famous that it offers many different ways to accomplish something which is great. But sometimes I continue to use an old habit or way because I have missed that there is a newer and better way, and the MCUXpresso Eclipse IDE is no exception to that. In this article I show a few ways how to use the mouse even more productive.
I admit: my work laptop machine is running a Windows 10 OS by default. But this does not prevent me running Linux in a Virtual Machine (VM). Each host platform has its benefits, and I don’t feel biased to one or the other, but I have started using Ubuntu more and more, simply because I have worked more on Embedded Linux projects. While I have used mostly Windows with Eclipse for NXP LPC, Kinetis and i.MX platforms in the past, I started using Ubuntu too from last year with the NXP MCUXpresso SDK. I did not find much documentation about this on the web, so I thought it might be a good idea to write a tutorial about it. So here we go…
LoRa and LoRaWAN is getting the de-facto wireless IoT network in my area. No surprise that traditional telecom providers like Swisscom trying to monetize the ‘Internet of Things’ area. Luckily there is an open and free alternative: https://www.thethingsnetwork.org/. Volunteers, enthusiasts and members in the different TTN communities build gateways and offer free LoRaWAN network access. I wanted to contribute to that grassroots movement with building my gateway, providing LoRaWAN access to my neighborhood.
Most of the time software needs some way to configure things: depending on the settings, the software will do different things. For example the software running on the microcontroller on top of the Raspberry might have the OLED LCD available or not:
Raspberry Pi and tinyK22 (NXP Kinetis K22FN512) with OLED LCD
Sometimes I start a project with an ARM microcontroller, and in the middle of the project I find out that it was a wrong choice at the beginning and I need to switch the microcontroller derivative or even the used ARM core. With little knowledge of the project structure and the files needed, such a switch is not the easiest thing, but definitely possible.
I really love tiny and bread board friendly boards, especially if they are very affordable and can be use with Eclipse based tools. So I was excited to see the NXP LPC845-BRK board to be available at Mouser, so I ended up ordering multiple boards right away. Why multiple? Because they only cost CHF 5.95 (around $6)!
In the age of high-resolution graphical LCDs using a character display might look like a bit anachronistic. But these displays provide a lot of value for me as they are robust, available in different shapes and number of lines. And such a character display can be a better solution for an industrial application.