Tutorial: Using the FRDM-KL25Z as Low Power Board

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

132 micro amps!

Continue reading

FRDM Board Bootloader fails with Windows 8.1 Preview

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.

Continue reading

FRDM Board not responding? Check your Virus Scanner!

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…

Continue reading

Zumo Robot assembled

This week we were busy with building and documenting the first robots based on the Zumo Robot Chassis PCB.

Chassis Base PCB

The chassis is designed to hook up the FRDM-KL25Z board from Freescale. It is using parts from Pololu (chassis, motors, DC-DC converter, line sensor, H-Bridge, encoders):

ZumoBaseBoardOverview

Zumo Base Board Overview

Continue reading

Overview of ARM Microcontrollers and Tools

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.

Continue reading

Optimized BitIO_LDD Programming with Processor Expert

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:

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

Luckily, there is a way to hack around this 🙂

Continue reading

Zumo Robot Chassis PCB arrived!

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

Intro Zumo PCB TopSide

Continue reading

Mini Sumo Robot with Proximity Sensors

The new semester is approaching fast! And I’m under pressure to get everything lined up and ready. This time, I want the students of the INTRO (Infotronic) course at the Lucerne University of Applied Sciences and Arts to have some fun with building and programming Mini-Sumo Robots 🙂

Opponent View

No chance to escape!

Continue reading

Mini Sumo Robot Competition running with FRDM-KL25Z

Rigi Schwinget (Roman Koch) (Source: http://en.wikipedia.org/wiki/File:Turnerundsennenschwinger.jpg)

Rigi Schwinget (Picture: Roman Koch)

Every three years, there is the “Eidgenössisches Schwing- und Älplerfest” in Switzerland. A really big thing for us here. If you are not familiar with what this is, then have a read about the long tradition of  Schwingen in Switzerland.

Wondering what “Schwingen” or wrestling has to do with a technology blog? It is about having fun with robots!

Continue reading