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.
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:
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.
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
Git is now my favorite version control system. Git and GitHub are very powerful, it has (nearly) all features I can think about, and best of all: As a distributed version control system, I can work with it, even if disconnected from the network :-).
There are many standalone and IDE integration available for Git. Beside of using TortoiseGit, I’m using the eGit Eclipse integration. This post is about how to install eGit in Eclipse, particularly in CodeWarrior for MCU10.4.
Freescale has added a new Freedom board: the FRDM-KL46Z:
FRDM-KL46Z with Box
My opinion? The best Freedom board so far, I love it!
For my embedded systems lecture I need a wireless connection to the robot we will develop during that course. So far I have SMAC (IEEE802.15.4) and Bluetooth worked out. But that IEEE802.15.4 (ZigBee) is expensive, and the cheap Bluetooth modules are great for robot-to-host connection, but not for swarm robots which need to communicate to each other. Alex Vecchio (see this post) pointed me to a $2.75 (!) wireless module featuring the Nordic Semiconductor nRF24L01+. Exactly what I needed, with an incredible low price :-).
nRF24L01+ Module Detail
Summer finally has arrived in Switzerland. Yes, I live in a moderate climate zone, but if the outside temperature goes above 28-30° Celsius as these days, then sleeping at night is not that comfortable as it should be in my view. Luckily, I’m in a good constructed house with good insulation, so it takes a few days until it heats up. But I love to keep the temperature below 25° Celsius, especially at night. I do have a heating system which combines geothermal and solar heating. The question is: how can I use it for cooling during hot summer days? The solution: some extra plumbing, a Freescale Tower system and the Freescale FRDM-KL25Z board 🙂
FRDM-KL25Z with Arduino Data Logger Shield controlling Heating/Cooling System
The Freedom boards FRDM-KL25Z RevE and FRDM-K20D50M make it easier to use it as USB Host device, as they come with a special jumper to provide 5V to the USB device, so my earlier ‘hack’ is not needed any more :-). After I had USB MSD Host working for the FRDM-KL25Z, it was much harder to get the USB stack working for the FRDM-K20D50M board, because somehow the example Freescale provided with their USB stack refused to work properly on my board. After debugging it for several nightly hours, I decided to take my working Processor Expert project for KL25Z and added support for the K20. And the good news is: since tonight this is working :-).
FRDM-K20D50M as USB MSD Host
While working on a project for the FRDM-K20D50M, I faced a problem: I was running out of SRAM for my application. The GNU linker reports: “section `.bss’ will not fit in region `m_data'”: 😦
bss will not fit in region m_data
But my device has 16 KByte of SRAM, and I knew I use much less than 10 KByte. So what is the problem? Continue reading
MCU on Eclipse 