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:
No Source Available, debugging in assembly
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:
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.
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
With the GNU compiler and linker I can place variables into custom sections (see “Defining Variables at Absolute Addresses with gcc“). This article is about how to get the section start and end address so I can for example access that range in my code. Or in general ways: how to use symbols defined in the linker script accessible in the C source code.
Command line tools to build applications are great. But productivity goes up if I can use the standard Eclipse environment with GNU tools. This tutorial is about how to use standard and free GNU and Eclipse tools to build my FreeRTOS application for the ARM Cortex-M4 on i.MX7 🙂 :
Eclipse used to build FreeRTOS applications for M4 on i.MX7
Playing with RFID and NFC is definitely fun :-), and they are everywhere! For a research project I’m exploring different RFID tags and solutions. I several types around for a long time, but never found the time to actually work on it, so last nightI thought I give it a try, and I have it working with GNU ARM and Eclipse, powered by the NXP FRDM-K64F board 🙂
This is the third part about ARM Cortex-M and how the interrupts are used. In Part 1 I discussed the Cortex-M interrupt system and in Part 2 I showed nested interrupt examples. This part is about FreeRTOS and how it uses the Cortex-M interrupt system.
In “ARM Cortex-M, Interrupts and FreeRTOS: Part 1” I started with the ARM Cortex-M interrupt system. Because the ARM implementation cann be very confusing, I confused myself and had to fix and extend the description in Part 1 :-). Thank for all the feedback and comments!
Originally I wanted to cover FreeRTOS in Part 2. Based on the questions and discussions in Part 1 I thought it might be a good idea to provide visual examples.
The ARM Cortex-M microcontroller are insanely popular. And it features a flexible and powerful nested vectored interrupt controller (NVIC). But for many, including myself, the Cortex-M interrupt system can be counter-intuitive, complex, inconsistent and confusing, leading to many bugs and lots of frustration :-(.
ARM Cortex-M7: NXP KV58
Understanding the NVIC and the ARM Cortex-M interrupt system is essential for every embedded application, but even for if using an realtime operating system: if you mess up with interrupts, very bad things will happen….
3.5″ Diskette Drives are not widely used any more: CDs, DVDs, memory/thumb drives and downloads from the web are the usual distribution method these days for software. Back a few years ago, software was distributed on one or many 3.5″ diskettes, and even before that time on 5 1/4″ floppy disk drives. So what to do with all these not-used-anymore hardware? Play music with it 🙂
My wife tells me that I have too many boards on my desk. That is only *partially* correct: there are many, but not *too* many. But I’m working on too many tasks, but that’s a different aspect :-). I’m using more and more the Kinetis SDK V2.0, and as a result of this I have multiple SDKs installed on my machine. Because with the SDK V2.0 I get a download for each device/board installed (see “First NXP Kinetis SDK Release: SDK V2.0 with Online On-Demand Package Builder“). So my list of SDK folders is growing, as shown with the ‘New SDK 2.x’ wizard in Kinetis Design Studio:
Multiple Kinetis SDKs
The same time, the amount of free disk space is reducing. What if I could combine all these SDK’s?
“Learning-by-doing” is one of the core principles of my embedded systems and robotics course at the Lucerne University. For this the students apply what they learned using a robotics platform. In earlier semesters we did a Sumo battle at the end. This time the challenge was to build a remote controller plus to add the ability to explore and solve a line maze: