P&E has a new version of their GDB/Eclipse debug plugins available on their Eclipse update site, and it comes with to great features: Real Time Expressions (show variables while target is running) and FreeRTOS thread awareness 🙂
The concept of Linux (Open Source, broad developer base and broad usage) is a success story. While there is a lot of diversity (and freedom) in the Linux world, Linux is Linux and again Linux :-). And the world has (mostly) standardized on Linux and its variants on the high embedded system side.
On the other side, the ‘middle and lower end’ Embedded world is fragmented and in many aspects proprietary. So it was no surprise to me when the Linux Foundation announced the ‘Zephyr’ project back in February 2016:
“The Linux Foundation Announces Project to Build Real-Time Operating System for Internet of Things Devices. Open source Zephyr™ Project aims to deliver an RTOS; opens call for developers to help advance project for the smallest footprint IoT devices.“
Ζεφυρος (Zephyros) is the Greek good of spring and the west wind. Obviously this inspired the logo for the Zephyr project:
To me, one of the most frustrating things working with ARM Cortex-M cores are the hard fault exceptions. I have lost several hours this week debugging and tracking an instance of a hard fault on an ARM Cortex-M0+ device.
In “Low Power LCD: Adafruit Breakout Board with Sharp Memory Display” I used a 96×96 Sharp Display (LS013B4DN04) with the Adafruit breakout board, but because that one seems to be EOL (End Of Life), I searched for a replacement. I have found the 128×128 pixel version (Sharp LS013B7DH03), and best of all, it is pin compatible :-). With a small tweak of the driver, it works :-):
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 🙂
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…
Time is passing by so fast, and the year end is approache fast! I’m pleased to announce that a new release of the McuOnEclipse components is available in SourceForge:
- Percepio Trace V3.1 for FreeRTOS which includes both Segger RTT continuous streaming and snapshot tracing in a single API
- Generation of sources and drivers so they can be used without Processor Expert using McuLibConfig, removal of dependency to NXP Kinetis SDK: components use a generic API approach to have them working with other SDKs.
- New contributed ExceptionsHandler component
- Callback Setter and Getter in USB CDC stack for simpler option handling
- GenericTimeDate with flexible RTC support and added Unix Timestamp functions
- LongKey events in Key component
- FreeRTOS with optimized task selection on Cortex-M4/M7
- Many smaller bug fixes and enhancements
The Hexiwear device is a great and versatile device with two microcontrollers on it. Developing firmware on a Hexiwear means changing what was originally on it. And sometimes it happens that I’m not sure if the changes are for good. Or that I accidentally destroyed the firmware on the NXP Kinetis KW40 BLE microcontroller :-(. So I had to find a way to restore the original firmware, and this is what this post is about.
For many of my applications I need to measure a distance. I have used ultrasonic sensors, but there view angle (beam) is not able to detect smaller objects, it very much depends on the object surface and angle, it is slow and not very precise. I have used infrared sensors, but here again it depends on the infrared reflection of the object in range, it depends the amount of reflected light is not really telling much about the distance, and yet IR reflection is subject of material and object targeted.
But there is yet another sensor type to consider: ToF! ToF (or Time-of-Flight) sensors have a built-in LIDAR: The sensor is sending out light pulses and measures how much time it takes for the light to come back. Similar to ultrasonic sensors (see “Tutorial: Ultrasonic Ranging with the Freedom Board“), but instead of ultrasonic it uses an infrared laser light. Or think about a radar system using an infrared laser light.
About a year ago, on December 7th 2015, Freescale and NXP have announced the completion of their merger. Now it is Qualcomm which wants to acquire NXP? It looks like these mergers are happening faster and faster. The reality is that merging products take more time than anticipated, and nearly one year later I can see the outcome of what comes out of the marriage between Freescale and NXP or between Kinetis and LPC: NXP has announced the MCUXpresso software and tools for Kinetis and LPC microcontroller:
The year is coming to an end, the Holiday season is approaching. In case you are looking for a nice present: I have completed my version of a sand clock: a clock writing the time into sand:
If you are interested to build your own version, I have documented the different steps with tips and tricks…
The good thing with failure is: it is an opportunity to learn :-).
So here is a case: For a STEM roadshow (see “MINTomat: World’s Most Complicated Bubble Gum Automata?“), we have produced in a rush an autonomous robot with a shiny printed 3D cover:
How to fascinate kids for technology? Show them that engineering is fun :-). At the Lucerne University of Applied Sciences and Arts we have created the ‘MINTomat’: a robotics system for STEM activities rewarding interaction with bubble gums:
Yes, pretty over engineered compared to a normal bubble gum automata, but that’s part of the fun :-).
It seems to me that not many developers use hardware trace? ARM indicates that maybe only <5% of developers are using trace. Too bad! Why are all the ARM Cortex microcontroller vendors putting a powerful hardware (and complicated!) trace engine into their devices, if only few developers are using it? Seems like a waste of silicon and an unnecessary price adder? Well, hardware trace can be a life saver: Because only with hardware trace the most complicated bugs and problems can be solved. And maybe because only the best are using it ;-).
A new McuOnEclipse components release was long overdue, so I’m pleased to announce that a new drop is available with the following major changes:
- Segger SystemView library with kernel time reporting
- GenericTimeDate supports different hardware RTC devices
- Utility with little endian packet handling functions
- Shell Standard I/O handlers for USB CDC, Segger RTT and Bluetooth
- FreeRTOS and stack size reporting
- printf() support in Shell component
- Various small bug fixes and improvements