The FRDM-KL25Z Open Source Logic Analyzer based on SUMP presented here was already very useful with the added trigger support. But it was not capable to do a sampling rate above a few hundred kHz. That’s ok for slower probing, but not for anything with a higher speed. Using DMA (Direct Memory Access) instead of timer based sampling can remove that limitation :-).
FRDM-KL25Z used as Logic Analyzer on another FRDM-KL25Z board
Finally I have found some time over the past week-end to enhance my Zumo robot. After I had my line following robot based on the Pololu Zumo chassis and the FRDM-KL25Z, I thought it should be easy and logical to solve a maze. Logical: yes. Easy: not that much. In fact it took me longer than expected. As always, there are a lot of tiny and important problems to solve (the maze alone was easy 🙂 ).
Zumo in the maze
For many of my applications I’m using a PWM (Pulse Width Modulated) signal. One example is the motor driver used in this project where I use one PWM signal for each motor. Another usage of PWM is to control the brightness of an LED. Processor Expert makes usage of the PWM hardware easier. Still, for some settings it is good to have the resulting signals in mind. So in this post I’m showing how the settings impact the PWM signal generated.
I knew about mbed already for some time: watching students using it for an NXP enabled board. Pretty cool stuff: mbed is an online IDE and compiler with tons of software libraries for the supported platform. So I was dreaming to have something like this for my own boards like the Freedom board. But because mbed only supported two dedicated NXP boards, that was a road block.
But then mbed announced recently that the mbed SDK is open source. Wow, that is interesting! And finally the announcement last week: mbed supports the KL25Z Freedom Board. Now they have my attention :-).
Probably I need to add 3rd monitor to my laptop system, or maybe I’m not organized enough. But as a matter of fact: I want to have as many source files as possible open in Eclipse. But there is simply not enough screen real estate to show them all:
Many source files open
With that many source files open, I need an effective way to switch between the files.
Eclipse is a good IDE. At a first glance, it does the job. Good enough. At least for myself, I was not that much excited when I used it the first time. I came from the Microsoft Visual Studio world, and have used many other proprietary IDE’s. So Eclipse was just ‘yet another one’. But what Eclipse makes really great is the incredible wealth of functionality which is not visible right away. Yes, this is the same for any other software tool: it takes time to explore, and once you know things well, you do not want to switch or even consider something different. Same for me.
The other thing is: after some time, I get used to things, and I do not appreciate it that much any more. Only until someone reminds me that maybe things are not that well-known? This is what happened to me two days ago: I did some editing in Eclipse, while a colleague was watching me doing this. Then he said something like this
“Hey, what did you do? What was that?!? How did you do that?”
I do not remember his exact words, as I was surprised as well. I did not do anything special? Kinda standard Eclipse thing. Well, maybe not.
Because my first line following robot was this week at the Embedded World conference in Nürnberg, I have constructed another one around the Freedom FRDM-KL25Z board. It is based on Pololu part items and the Arduino motor shield, plus using a Bluetooth module I have used in an ealier post.
Pololu Line Following Robot with FRDM-KL25Z
Sometimes things take longer than anticipated. And this is definitely the case for my USB MSD Host project where I wanted to use a USB memory stick with the Freedom FRDM-KL25Z board.
Memory Stick attached to the Freedom Board
But finally, I have things working. At least most of the time ….
After working on an ADC example, a DAC one was missing. Julio E. Fajardo is a reader of this blog, and he was so kind to send me an example project for the FRDM-KL25Z. The example is able to produce produce different waveforms with the DAC. The project has two examples which they are enabled/disabled in main(). One example waveform the sawtooth:
Sawtooth_FDRM_DAC
In “Using the Reset Button on the Freedom Board as User Button”, I had the problem to find out why a setting did not make it into my generated code. There is the fundamental question: “How does a setting impact my microcontroller register settings?”. There is an answer to that question: The Configuration Registers view:
Configuration Registers View
MCU on Eclipse 