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.
Eclipse based IDE’s have typically one limitation: the IDE has not much scripting capabilities. Yes, I can use things like JUnit for testing, but if it comes to build and debug C/C++ applications, then support gets really rare. An exception to this is CodeWarrior for MCU which features a command line version of the IDE which can be used for test automation as I used it in one of my tutorials. What I missed so far is to have a command line interface for Processor Expert to generate code. This is now possible with CodeWarrior for MCU10.5 :-).
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 multimeter pictures ;-)….
The Eclipse IDE is in my view the best IDE in the world :-). But it is not the fastest one: All the functionality and comfort has a price, and such a Java and highly flexible IDE requires its resources. The Eclipse community is continuously addressing that concern, and for example the Eclipse Juno 4.2 IDE in CodeWarrior for MCU10.5 shows this nicely: things are much smoother compared to the Eclipse Indigo 3.7 in MCU10.4. But if you feel that you do not want to use Processor Expert because it is too slow, then I have a trick how to improve performance by a factor of 10 :-).
Sometimes I have ‘multiple definitions’ in my projects: this means that I have functions defined in one source files, and I need to ‘overwrite’ one or more with a version in another source file. For example I have a source file with utility functions (Utility.c), and I want to overwrite some of these functions with a different implementation in a different file (MyUtility.c). How can I do this?
Microsoft has released the Windows 8.1 Preview. So you can try out the next update of Windows 8. In short: Do NOT use Windows 8.1 Preview if you are using a Freescale FRDM board! Otherwise you will not be able to change the OpenSDA firmware (MSD or debug application).
❗ Update: P&E has released a new firmware v114 which combines USB CDC, MSD bootloader and debug application, and this firmware fixes the issue described in this post.
Well, I have not used it personally: I never use ‘test’ or ‘preview’ versions on my ‘production’ machine. It is ok to try things out on separate ‘scratch’ machines, but not on something I need to have stable for my work. Well, some of the students in my INTRO class were not able to resist and downloaded and installed Windows 8.1 Preview on their machines. With the result that the OpenSDA Bootloader does not work with Windows 8.1 Preview:
❗ It seems that the problem exists as well with the Windows 8.1 ‘final’ release.