For my RNet stack I need a way to identify nodes in the network using a unique address. What I need is Media-Access (MAC) address. Base on such a unique address I can assign short addresses (e.g. with a DHCP or similar protocol to automatically assign shorter network addresses). So how to uniquely identify my network nodes?
The Freescale Kinetis microcontroller have nice feature: they have a Unique Identification Register (UID) which would be a perfect fit for a MAC address :-).
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.
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 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)
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).
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.
In case you have this problem with the FRDM boards: You are using the FRDM bootloader mode (it shows up as BOOTLOADER) or the MSD mode (e.g. it shows up as FRDM-KL25Z) (see OpenSDA on the Freedom KL25Z Board) and it does not respond any more, or does not work as expected, then read on…
I’m working with a student on building a small autonomous robot platform, based on the FRDM-KL25Z board. We integrated new software modules, compiled and linked, and then downloaded the application to the board. While debugging and stepping through the application startup, I had this:
The Debugger has lost communication on connection
Outsch! That’s not good. Even worse, trying to connect again to the board failed :-(. What happened?
If you are following my recent posts, then you know I started using USBDM on OpenSDA as an alternative run control solution. Now with the advent of MCU10.4, the question is: how to use USBDM with it, because the USBDM installer obviously only knows the version up to MCU10.3?
Ok, this one might not work for everyone. And maybe I’m seeing a ghost. But a nice and real one, at least for me :-). It seems that with the new CodeWarrior for MCU10.4 installation I was able to recover a bricked OpenSDA FRDM-KL25Z board
Teaching at a university means to work in a very special environment. What students love is ‘Open Source’: because it allows them to ‘see’ things and learn from the technology. The other thing is: students have a low budgets, so they appreciate if they can use inexpensive or low-cost hardware and software. The FRDM-KL25Z Freedom board for sure meets that low price, and no extra programming device needed.
Now they are building their own boards, and they wish to program and debug it. They can borrow the Segger J-Links and P&E Multilinks we have available at the university. But why not use the Freedom board as ‘hobby’ debug and programming solution? As explored in “Using the Freedom Board as SWD Programmer“, they can use the default factory installed OpenSDA to program another microcontroller of same type. But not to debug it.
While writing the ”Using the Freedom Board as SWD Programmer” article, I was looking into USBDM. USBDM has added in January 2013 support for OpenSDA. But at that time, it was somehow not working for me, and I had not enough time to find out what the problem was. Time to get that fixed. Good news: With help and tips from the USBDM community, I have it finally working
“As an engineer, you should ask for the best tools available. Spending money for better tools can make the difference between finding a problem quickly, or wasting days or weeks, and ultimately failing a project.” (unknown)
I had to learn it the hard way: some ‘hard-to-find-problems’ sometimes only can be found with some amount of luck, or with using a good trace solution. CodeWarrior already supports trace, such as using the MTB on the Cortex-M0+. But with this I’m limited to the on-chip trace buffer or on-chip RAM, which is better than nothing. But to solve the real hard problems, a bit of more power and memory is needed. And here where the P&E Tracelink comes into play: with 128 MByte trace buffer it would allow me to record a lot more trace data :-).
Debugging is usually a ‘stop-inspect-continue’ process. That does not work very well for watching a system which continuously changes its state. For this usually I toggle an LED, or write things to the console to watch with a human eye what is going on. But there is something very powerful in the CodeWarrior debugger too: to display variables and memory content while the target is running.
The OpenSDA on the FRDM-KL25Z board is a cool feature: I do not need any external debugging device to program and debug my board :-). But my KL25Z custom board will not have that OpenSDA on it: first because it would add additional costs, and I do not see a way how I could use it for my board, see this forum discussion. I better start using a JTAG debugger for my Freedom board to have everything in place.
What I need to add to the black Freedom board is the JTAG header: