Debug External Processors with USBDM and Freedom 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 🙂

USBDM Debugging another FRDM-KL25Z

USBDM Debugging another FRDM-KL25Z

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A new Freedom Board: FRDM-K20D50M with ARM Cortex M4

Freescale/Farnell/Element14 announced last week a new Freedom Board: the FRDM-K20D50M :-). As you can expect, I was not able to resist, and ordered one from my local Farnell store right away. So I did my first steps with it on this sunny and wonderful weekend (yes! we skipped Spring Time and entered Summer Time right away!).

I do not need to compare the board with the previous Freedom boards, as I have found an article here. I a nutshell: I get pretty much the same as with the FRDM-KL25Z, but instead of an ARM Cortex-M0+, it has an ARM Cortex-M4!

The new FRDM-K20D50M Board

The new FRDM-K20D50M Board

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Extended Driver for the MMA8451Q Accelerometer

In “Tutorial: Accelerating the KL25Z Freedom Board” I used the MMA8451Q accelerometer on the FRDM-KL25Z board in a very primitive way: I’m reading directly some low-level registers from the device through an I2C low-level component. No calibrating, no special device feature setting, only raw values. Since then, things have been evolved: In “Tutorial: Creating a Processor Expert Component for an Accelerometer” I started to create a driver for this accelerometer, and since then a lot more functionality has been added.

Tracing Accelerometer Values to the Shell

Traced Accelerometer Values to the Shell

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Stepping Backwards while Debugging: Move To Line

It happens to me many times: I’m stepping with the debugger through my code, and ups! I made one step too far!

Debugging, and made one step over too far

Debugging, and made one step over too far

What now? Restart the whole debugging session?

Actually, there is a way to go ‘backwards’ 🙂
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First Steps with the P&E Tracelink

“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 :-).

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Decoding S19 Files

I’m recently dealing again with S19 (S-Record) files. I can easily generate S19 files from my ARM .elf files, but what I need is a simple decoder of the file format.

The good thing is: such a decoder is provided with CodeWarrior for MCU10.x 🙂

That capability is built into the Decoder.exe which is delivered with the Freescale S08 (or S12) tool chain, and is located inside the MCU\prog folder:

Decoder.exe inside MCU prog Folder

Decoder.exe inside MCU prog Folder

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Tutorial: Creating a Processor Expert Component for an Accelerometer

If you are a frequent reader of this blog, then you know: I’m a big fan of Processor Expert components. While there are many Processor Expert components delivered with CodeWarrior, it lacks many components and device drivers beside of the normal on-chip peripherals. But value gets added to an embedded project with all the external devices, sensors and actuators. That’s why I have created many more components which are available on my GitHub site. Readers of this blog have asked several times to create a tutorial on how to create a Processor Expert component. So why not working on that on a long Easter weekend full of cold rain and snow?

So here we go: a tutorial how to create a Processor Expert component for the MMA8451Q accelerometer found on the FRDM-KL25Z board:

MMA8451Q Accelerometer on the FRDM-KL25Z Board

MMA8451Q Accelerometer on the FRDM-KL25Z Board

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Copy of Processor Expert Components

Many times I have Processor Expert components carefully configured in one project, and then I want to have the same thing in another project. There is actually an easy way to carry out this: to copy components from one project to another.

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Version Control with Processor Expert Projects

Using a version control system for software development is a standard procedure today. While things are pretty clear for ‘standard’ Eclipse projects, it is not that easy for Processor Expert projects. I’m using Processor Expert projects with Git and SVN (Subversion). I want to share here tips how to use Processor Expert projects with a version control system. Screenshots and vocabulary are for TortoiseGit and Git, but applicable to any other VCS (Version Control System).

Git Repositories View in Eclipse

Git Repositories View in Eclipse

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Maze solving FRDM-KL25Z Robot goes backward for Dead-Ends

The maze solving robot based on the Freedom FRDM-KL25Z and Pololu Zumo shield has new features:

  1. For dead-end paths, instead turning around, the robot is driving backward
  2. Higher speed for going forward/backward/turns
  3. In the finish area, the robot turns around
  4. It reverts the solution path, so the robot can directly run from the finish area to the start
FRDM-KL25Z Robot on Practice Area

FRDM-KL25Z Robot on Practice Area

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