As noted in my post on gcc and FreeRTOS, some code might be very sensitive to compiler optimizations. While porting code from the Freescale ARM/Kinetis compiler to the gcc compiler as in MCU10.3, I have found way how to force compiler optimization levels in my source code.
In my earlier tutorials “Enlightning the Freedom KL25Z Board” and “Accelerating the KL25Z Freedom Board” I have not used an RTOS. In this one I’m creating a project from scratch and run it with the open source FreeRTOS operating system, using the FRDM-KL25Z Freedom board. MCU10.3 comes with gcc, and is nicely integrated with Eclipse and CodeWarrior. With this tutorial, it is possible to get an RTOS up and running on a Kinetis device very quickly.
I have a KL25Z which has 128 KByte FLASH and 16 KByte of RAM. What I want to explore is if things could fit as well to the KL0 family where the smallest device has only 8 KByte of FLASH and 1 KByte of RAM. Can this work?
I have not received my pre-ordered boards yet, but at least I have now one of the new black ones, see this post. And I have good and bad news.
Good news: A reader of this blog has sent me pictures of his board he received yesterday:
Pre-ordered Freedom board with headers
My earlier posts were around the Kinetis gcc compiler which comes with CodeWarrior for MCU10.3. MCU10.3 comes as well with the Freescale Kinetis compiler as in MCU10.2. In “S-Record Generation with gcc for ARM/Kinetis” I explored how to generate S19 or other output files with gcc. However, you only can produce one file format at a time. What if I need multiple formats or a different format. What if I need to do the same with non-gcc build tools? S-Records are usually easy as supported in the linker. Other formats need a bit more plumbing. So this post is how I can create and manipulate the different output formats, so I can use it with a bootloader.
Today I attended the regional ‘Design with Freescale’ seminar. It had a part with a hands-on training using PEG for the Tower K60 + TWR-LCD board. It was the first time I had my hands on PEG which is a good learning experience. I learned that it is possible to fill more than 200 KByte of Flash with a simple LCD Touchscreen application which only has two screens, two buttons, a static text and two small bitmaps ;-).
Working with the Freescale S08 and S12 build tools, there is something I really appreciated: that the linker reports on the console the code size of the application:
S08 Linker in Eclipse reporting the code size
This is especially handy as it allows you to see the impact on code size immediately e.g. if I change a compiler option or do a source code change. Simple and easy. Yes, I could get that kind of information from the linker map file too. But this means I need to open that file, scroll down/etc: many steps just to find out the code size.
In “Tutorial: Enlightning the Freedom KL25Z Board” I used the RGB LED on the FRDM-KL25Z board. This tutorial extends it to use the MMA8451Q inertial sensor on the board which is connected through I2C to the KL25Z processor:
Freedom Board Block Diagram with MMA8451Q (lower right corner)
The goal is show the accelerometer x, y and z-axis on the RGB LED.
P&E has released information and firmware instructions for using the OpenSDA, see pemicro.com/opensda. Future has posted a very useful article about using OpenSDA here. So time to upgrade OpenSDA bootloader and firmware v10.1. My FRDM-KL25Z board is a pre-production board, and I assume the production boards expected next week will have the new firmware on it. But it is always useful to know how to change/upgrade the firmware, as I expect there will be new versions of it in the future.
With my Freedom KL25Z board I’m using the GNU/gcc build tools and Eclipse/CodeWarrior. When I wanted to create an S19 file of my application using the GNU tools, this was not that easy to find out. So here are the steps to do this:
I open the project setting using the menu Project > Properties and go to C/C++ Build > Settings > Additional Tools and enable’Create Flash Image‘:
Additional Tools gcc Settings
The schematics for the Freedom board is now available on the element14 Freedom Board site (you need to log into the element14 community first) as FRDM-KL25Z Schematics (SPF-27556_D).pdf (314.7 K)). So time to write a tutorial how to use the LED on that board.
❗ Note: since this tutorial, the LED component has been simplified. So some of the steps below are much simpler and easer. Please see LED’s for Kinetis, simplified | MCU on Eclipse. I have updated this post with the new instructions and images.
In “FreeRTOS with GCC, Cortex-M0+ and Kinetis KL25Z Freedom Board” and “A Shell for the KL25Z Freedom Board” I have used that board with an RTOS: FreeRTOS. But it is really easy to use that board without an RTOS (‘bare metal’) too. In this tutorial I’m providing step by step instructions to use the RGB LED on the Freedom KL25Z board with Processor Expert and the open source LED component.
MCU on Eclipse 