A lot of stuff learned!

I’ve been playing around a lot with the Stellaris Launchpad board, looking around the stuff I never noticed that the besides the fact of being licensed with a BSD style license, the Stellarisware SW provided by Texas Instruments has a closed license for the various examples.

The basic files needed to create a program for the board, and basically for all the ARM processors are the following with binutils and gcc:

  • The program you want contained in a .c file.
  • A linker script due to the fact you don’t have an operating system running.
  • A startup code file that zeroes the .bss segment variables, copies the .data segment to ram and setups the NVIC vector table.
  • A Makefile to build everything easily.

The program and the Makefile can be done with not much worries, but the linker script and the startup code are quite difficult, at least for me, to understand and set up properly.

So I ended up building from scratch the whole files needed and licensed them with a BSD license (Basically, do what you want with them, just give me credit I’m happy if someone find them useful, you can contribute, but don’t blame me if it doesn’t work lol)

You can find them in this Github repository

Continue reading “A lot of stuff learned!”

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Stellaris Launchpad

So, I got my 2 stellaris launchpad boards from TI.

Launchpad
Stellaris Launchpad

Each board has 2 Stellaris LM4F120H5QR ARM Cortex-M4 MCUs. The nice thing it’s I’ve had them for less than 5$ with free shipment.

I’ve followed the getting started tutorial on a windows machine, as they suggested, using their Code Composer Studio 5, which is free for the launchpad board, with now limitation on code size or time.
I’ve noticed that the examples can be built with a GNU cross-toolchain for arm-none-eabi, like the codesourcery lite if you don’t want to build your own (Yeah, I’m lazy).
I just used my ubuntu pc to test that out, and it was kinda easy to build some sample!

First thing to do it’s downloading the toolchain from here, you’ll need to register on their site. The installation it’s pretty straightforward, just follow the instructions on the site, with the shell change and the adding of the bin directory to the path.

You can verify to have a working toolchain with this test:

arm-none-eabi-g++ –version

Next you need to download the StellarisWare software from here you’ll need to register in here too but also getting an approval.

After downloading the StellarisWare you should create a folder on your home directory:

cd
mkdir stellaris
cd stellaris

Then you just need to run unzip to extract inside your folder the content of the auto-extracting archive you downloaded.

unzip ../downloads/SW-EK-LM4F120XL-9453.exe

Then you’ll just have everything ready to work with that. Get inside a directory and just use make to build the project. The cross compiling and all the variables configurations are in the makedefs file in the stellarisware folder!

The only missing part until now it’s how you load to the compiled bin file into the microcontroller. On windows it can be achieved with the LMLoader program. In linux there’s no way at the moment usually with the ICDI controller on board, the only way it’s using a JTAG adapter connected on the breakout JTAG connector.

The nice thing it’s that there’s also a d DFU Bootloader on the chip, maybe with some work I could get it working and uhm that would be useful somehow.