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 🙂
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
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 🙂 :
In my previous article (see “Tutorial: First Steps with NXP i.MX7 and Toradex Colibri Board“) I have booted the i.MX7 on a Toradex CPU module. In this post I’m showing how to run a FreeRTOS application on that board.
As a standard procedure, I add some console functionality to my embedded applications. That way I have a command line interface and can inspect and influence the target system. One interesting hardware feature of ARM Cortex-M is Single Wire Output (SWO): it allows to send out data (e.g. strings) over up to 32 different stimulus ports, over a single wire.
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 tutorial goes through the steps how to create a blinking LED application, using Kinetis SDK and Processor Expert, using the TWR-KL43Z48M board from Freescale (now NXP):
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 :-(.
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….
I kind of hoped that after “Why I don’t like printf()” and all my other articles about printf and semihosting, that topic would be 200% handled and I won’t have to deal with any more. Well, I was wrong and underestimated how the Kinetis SDK is interfering with semihosting. And I underestimated how many of my readers are still using semihosting (even as there are other and better alternatives), so I keep getting questions and requests for help. That’s ok, and I hope I can help :-).
So here is yet again another post about how to turn on semihosting with Eclipse, GNU ARM Embedded and the Kinetis SDK v2.0. This time with the FRDM-K64F board:
Sometimes it is very useful to clean or build a selected set of files. For this I select the file(s) in the Eclipse Project Explorer and use the context menu:
In “Mother of Components: Processor Expert with NXP Kinetis SDK V2.0 Projects” I presented an approach how to use Processor Expert components with the NXP Kinetis SDK. This article is a tutorial how to create a blinking LED project with that approach, using McuOnEclipse Processor Expert components and the Kinetis SDK V2.0. As board the FRDM-K22F is used:
Eclipse based IDE’s have a powerful feature to make ‘variants’ of the same projects: Build Configurations. Build configurations are a powerful thing in Eclipse: they allow me to make ‘variants’ of a project. The project will share the common things, and I can simply tweak things one way or the other for example to produce a ‘release’ or a ‘debug’ binary of my application without duplicate the project.
Build configurations are manged through either the context menu on the project or with the top menu:
Unfortunately, now the NXP Kinetis SDK V2.0 does not include Processor Expert support (see “First NXP Kinetis SDK Release: SDK V2.0 with Online On-Demand Package Builder“). But at the Lucerne University we are using more than 150 different custom Processor Expert components we would like to use with that new SDK. So how to make them working with the Kinetis SDK V2.0? Using a Processor Expert as “the mother of all components”:
My embedded applications are implemented mostly in C, a few in C/C++. But all of them have one or few assembly files included too: Assembly programming is the needed to do low-level things so it is a natural part of a true embedded application. For example I use often an assembly file for the application startup code.
I have run into a nasty Eclipse CDT issue which deals with assembly files projects. Here is a quizz for you: can you spot the problem in my project below?
With Processor Expert projects it is very easy to change the heap and stack size: There is a setting for this in the Cpu component settings, under the ‘Build options’ tab:
As there is no Processor Expert in the NXP Kinetis SDK V2.0 (see “First NXP Kinetis SDK Release: SDK V2.0 with Online On-Demand Package Builder“), how to do the same in a SDK V2.0 project?
The world is changing, and the say is “change is good” :-). In the software and API world, change very often means that a change results into something broken. So I had battled with semihosting working on the NXP Kinetis parts, only to find out that it does not work any more with using the latest version 2.0. The semihosting output e.g. with P&E debug connection remains empty:
So how to fix this?
I’m using the FRDM-KL25Z in my classes, and that board is very popular: low price (<$15), reasonable features (48 MHz ARM Cortex M0+, 128 KByte of FLASH, 16 KByte of RAM), and many tutorials elsewhere and on McuOnEclipse :-).
For the next (Fall) semester I’m looking for alternative boards, and one is the Freescale (now NXP) FRDM-KL27Z: