I’m using FreeRTOS in most of my applications. There were only a few exceptions where an RTOS has to be used in safety critical systems: there usually it is not permitted to use any dynamic memory allocation because this adds the risk that a memory allocation could fail at runtime because of memory fragmentation or memory leak. And FreeRTOS uses a dynamic memory (heap) for the task stacks and the RTOS resources including semaphore, mutex and queues.
This is now a thing of the past. This week a new FreeRTOS Version 9 was released which does not need any dynamic memory allocation anymore: it is possible now to build completely statically allocated systems with FreeRTOS :-).
Dynamic and Static Memory Allocation in FreeRTOS V9.0.0
Time is passing fast, and many components have been updated to make the compatible with the NXP Kinetis SDK V2.0. As a highlight, besides of FreeRTOS the following components are now usable with the NXP Kinetis SDK:
It has been already two months after the Feb 2016 release, and so much things are going on, so a new release was overdue. Today I have released a new version of the McuOnEclipse components on SourceForge with the following main changes and features:
Kinetis SDK v2 with Processor Expert: Now many components can be used even with the Kinetis SDK v2.0 even with the Kinetis SDK not having Processor Expert included.
Updated Segger SystemViewer to v2.32a with post-mortem and static buffer support
Updated Segger RTT to v5.10u and fixed an issue with interrupts on Cortex-M4
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:
I’m using Processor Expert components for nearly every Freescale (now NXP) projects: for S08, S12, ColdFire, DSC and especially all the different NXP Kinetis devices. Not only because it makes software development fast and easy and allows re-use of software, but as well because Processor Expert has a good way to pack and distribute software components. Unfortunately Processor Expert is not any more included for the new Kinetis devices (see “First NXP Kinetis SDK Release: SDK V2.0 with Online On-Demand Package Builder“). So I have looked into an alternative and hopefully vendor neutral way to build and distribute software packages using CMSIS-Pack.
I have been asked to provide a command line shell example for a bare-metal (no RTOS) application, so here we go!
Having a way to communicate to the firmware on a board is essential for most of my projects: it is simply, incredibly helpful and easy to do (see “A Shell for the Freedom KL25Z Board“). This tutorial shows how to add a simple command line shell to the NXP Freedom board which then can be extended as necessary.
There are plenty of different software packages available for microcontroller these days from all the silicon vendors. Finding a good software package is one challenge, getting what I really need is another one. Freescale is now part of NXP since December 2015, so this is probably the first release of the former Freescale part now as NXP: The NXP Kinetis SDK Version 2.0.
It comes with an interesting distribution way: instead of downloading huge packages with all-and-everything in it, I can build it ‘on demand’ online and get what I need, on demand from a web-based front end:
For my home automation project with openHAB I want to attach Freescale (now NXP) FRDM (Freedom) boards so they can take care about the realtime aspects and to act as gateways to my other systems. One way is to use USB CDC (Serial over USB) as communication channel. USB has the advantage that it powers the board, plus I can attach multiple devices: up to four on the Raspberry Pi 2 and even more with using a USB hub. In a standard configuration with a USB WiFi and a USB HID (mouse plus keyboard) dongle I still can attach two Freescale (ahem, NXP) Freedom boards to the Raspberry Pi:
FRDM-K22F and FRDM-K64F attached to Raspberry Pi 2
One of the most important aspects for developing complex realtime applications is get insights into what is going on the target. Segger just has released a free tool which gives an incredible useful insight view and visualization:
In “Overview: From Snippets to Code Generation” I discussed several tools used in my development process. On tool which helps me a lot to get things done is Processor Expert. In this post I’ll give an overview about this tool and reasoning for the pros and cons of using it.