Tutorial: Using the FRDM-KL25Z as Low Power Board

Posted on October 20, 2013 by Erich Styger

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!

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FRDM Board Bootloader fails with Windows 8.1 Preview

Posted on October 12, 2013 by Erich Styger

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.

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Overview of ARM Microcontrollers and Tools

Posted on October 4, 2013 by Erich Styger

In this semester course, students (and myself too, of course :-)) are building a Mini Sumo Robot. That robot is using the Freescale FRDM-KL25Z board with an ARM Cortex-M0+ on it. Today I’ll give an introduction to the ARM core to the class, and timing is right: this morning I have found an excellent overview about ARM microcontroller and tools written by Jay Carlson.: Getting Started with ARM Microcontrollers.

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Optimized BitIO_LDD Programming with Processor Expert

Posted on September 29, 2013 by Erich Styger

In my tutorial “Bits and Pins with Kinetis” I showed how to use the BitIO_LDD approach for Bit I/O access. I do not like this LDD (logical device driver) approach for several reasons:

It requires an extra ‘device handle’ passed to the functions, even if such a device handle is not needed or desired.
The code efficiency/size is negatively impacted by this.

Luckily, there is a way to hack around this 🙂

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Zumo Robot Chassis PCB arrived!

Posted on September 28, 2013 by Erich Styger

Excellent news: I received this week the 40 INTRO Zumo Robot Base/Chassis PCBs, ready to bring the Zumo Robot project based on the FRDM-KL25Z board from Freescale to the next level:

Intro Zumo PCB TopSide

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New CodeWarrior for MCU10.5

Posted on September 23, 2013 by Erich Styger

On Friday, Freescale has updated CodeWarrior for MCU10 from V10.4 to V10.5, available on http://www.freescale.com/cwmcu10. I have not had much time to use it over the week-end, but here is a list of the things which in my view will make me switch my projects over to 10.5 and use it in my university classes:

Smaller: smaller setup and less disk space
Faster: faster debugging and flashing
Features: Eclipse Juno, detachable editor views, ‘unlimited’ breakpoints, simplified debugger attach/connect/download, and more.

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USB for the Freescale ARM Kinetis KL46Z and K21D50M

Posted on August 29, 2013 by Erich Styger

As I was so pleased with the FRDM-KL46Z board, that I have ordered the Tower version of it, the TWR-KL46Z48M:

FRDM-KL46Z with TWR-KL46Z48M

What I missed so far was USB support for the KL46Z. So time to have a quick look at board(s) and to add USB support for it.

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Kinetis ARM Cortex M4 DIY Board for $5

Posted on August 8, 2013 by Erich Styger

I love the Freedom boards, like the most recent FRDM-KL46Z for about US$15. But if I think that the ‘Freedom’ board is to big, cost too much and has too much on it, then here is one which is built for only US$5 :-): The MC HCK (pronounced “McHack”):