I was searching the internet for an open source network stack for my nRF24L01+ transceivers. But these stacks were either too heavy or had a restrictive or not really non-open source license behind it. I was very reluctant to start with something I think already should exist. Two weeks ago I decided that I just do it from scratch, and here I am: I have the basics working 🙂
Two FRDM-KL25Z with nRF24L01+ Transceivers
In case you are desperately looking a component in the components library view, but somehow it does not show up? For example I know there is component ‘InterruptVector’, but it is not present in the Components library view?
Where is the InterruptVector Component
Yes, I have been busy with all the different ARM Cortex Mx cores I’m using in my projects. But beside of the ‘ARM domination of the world’, there are other interesting processors out there. While the ARM cores have added DSP (Digital Signal Processing) capabilities blurring the boundaries between pure MCU and DSP processors, there is still a place (or niche?) for specialized DSP processors. The power of such processors is in the domain of fast signal processing, e.g. for intelligent power switches or for advanced motor control.
TWR-56F8400 Board and Box
Are you using IAR tools and you are jealous looking at what others can accomplish with Eclipse? You wish you could use your IAR build tools but taking advantage of Eclipse too?
I do not want to start a religious IDE war here ;-). At least for IAR, there is a way to bring both worlds together: having IAR build and debug tools integrated in Eclipse 
:
Using IAR Compiler and Debugger in Eclipse
For the Eclipse and Processor Expert lovers of this world: there is another Eclipse based IDE you can use: ThunderBench made by Emprog:
ThunderBench for ARM Eclipse Startup Screen
They support a range of ARM based devices, including the Freescale ones I’m using. So I downloaded the v3.24 30 day trial from their download page last week. Finally I have found some time to try it out. Could this be an alternative to use my Freescale FRDM boards with Processor Expert?
This week I saw on the IAR website that they have released the new IAR Embedded Workbench v6.7 for ARM. I was still on 6.5 using the free code size limited ‘Kickstart’ version), so I thought it would be a good time to upgrade to the v6.7. And there are good reasons as the connection to Processor Expert makes things much easier now.
If you were wondering why I am pushing the FRDM-KL25Z boards hard to the micro-amps, then have a look at this:
nRF24L01+ Network Nodes
The five boards are the first set of prototypes with a FRDM-KL25Z for a battery operated wireless sensor network based on the nRF24L01+ 2.4GHz transceiver.
If you read my posts, then you probably know: I *love* the FRDM boards! But: Freescale has only the lower-end processors available with a FRDM board (yet?). As I need something more powerful for my Raspberry Pi Camera project, I’m using Tower boards instead. This gives me an ARM Cortex-M4 with 120 MHz, Floating Point unit plus 128 KByte SRAM :-).
For that project I need USB. So this post is about using the TWR-K60F120M and TWR-K70F120M with USB connectivity, using the USB CDC device class as example. Initially I thought I can do as easily with the FRDM boards. It turned out, that things are not that easy.
Freescale TWR-K70F120M Tower Board
Freescale might not have thought about this: how to use Freescale boards and silicon to develop for non-Freescale silicon? 😉
I tinkered around using the FRDM (e.g. FRDM-KL25Z) board as a general purpose programming or debugging device. See the links to the posts at the end of this article. I have used it to program and debug other Freescale ARM processors. It requires board changes and the usage of a different OpenSDA firmware which has its own limitations (no USB CDC serial bridge). But for about $15-20 I have a device to program my own external boards :-).
If you are using Keil tools, then the good news is: With CMSIS-DAP you can debug any other (even non-Freescale) ARM device as long it is supported by the IDE :mgreen:
FRDM-KL25Z debugging the nRF51422-DK (Source: Keith Wakeham)
The FRDM-KL25Z is a great board: inexpensive (around US$15), small form factor, has easily accessible pins, and has a low power (capable, at least) microcontroller, and comes with an embedded debugging interface. So why not using this board right away ‘as is’ for a low power battery operated device? Great idea, you think? Yes, I thought too. Only to find out that the board needs 20 mA out of the box.
The good news is: It is possible on a week-end to get this 150 times better down to 132 μA, with an RTOS running all the time :-). I invite you to join a journey with board modifications, jumpers, schematics and many multi-meter pictures ;-)….
132 micro amps!
MCU on Eclipse 