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.
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:
Luckily, there is a way to hack around this 🙂
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
On Friday, Freescale has updated CodeWarrior for MCU10 from V10.4 to V10.5, available on http://www.freescale.com/cwmcu10. I have not had much time to use it over the week-end, but here is a list of the things which in my view will make me switch my projects over to 10.5 and use it in my university classes:
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 🙂
No chance to escape!
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!
The ARM Cortex specification includes the ‘SysTick’ (System Tick Timer): a dedicated system timer which is intended to be used as time base for an RTOS. While technically it would be possible to use any periodic interrupt timer, I’m using as well the SysTick for my FreeRTOS ARM ports. And because Processor Expert includes a nice timer interface, I’m using the TimerUnit_LDD:
TimerUnit LDD for SysTick
While this is great for flexibility, it has its price in efficiency. That TimerUnit_LDD adds overhead. So I want to get rid of the TimerUnit_LDD and use a more efficient way.
As I was so pleased with the FRDM-KL46Z board, that I have ordered the Tower version of it, the TWR-KL46Z48M:
FRDM-KL46Z with TWR-KL46Z48M
What I missed so far was USB support for the KL46Z. So time to have a quick look at board(s) and to add USB support for it.
“A picture says more than 1000 words.”
I don’t know the source of that quote, but for sure it is true for every developer and engineer too. Engineers need to work a lot with numbers. But numbers can be transformed into pictures and graphs which can make complex things and relationships easier to understand. Verifying proper functionality of a PID closed loop controller or watching sensor values with a nice plot is definitely something very useful. Would it not be great to watch sensor data changing over time in a chart like the one below?
Accelerometer Graph
One way is to export data and then show it e.g. in Excel (which has been great chart functions). But even better, if this could be done directly with data provided from the target board? If you think this is hard to do, then I can show you how this can be done in a few steps with the help of a very nice tool: FreeMASTER 🙂
For many projects I need to store configuration or sensor data. For this I’m using either an SD card or program the internal flash memory of the microcontroller. Using the internal flash is a good thing as it does not need an external component. However, the typical number of programming cycles is limited to 10k-50k which is a limiting factor if data has to be recorded over a long time or very often. That’s why I’m using the very popular external 24xx external EEPROM devices from Microchip.
24LC512 connected to FRDM-KL25Z
MCU on Eclipse 