Control a robot with a watch

Some six months ago Texas Instruments announced the Evalbot, a development platform for their Stellaris ARM Cortex-M3 microcontrollers in the shape of a little robot. It took me a while to get hold of one, but now I have one driving happily around in my living room. It is actually a pretty neat and cleverly engineered kit that you have to assemble yourself. Most parts are made out of PCB material – the two wheels for instance are each made of three disks and a rubber ring – the rest are mainly nuts & bolts. Two little motors with gears drive the wheels and everything is powered from three AA batteries.

The Evalbot is not a gadget; it is a powerful development board with wheels. In the center off the disk-shaped board sits an LM3S9B92 ARM Cortex-M3 controller (256 KB flash, 96 KB RAM and more peripherals than you will probably ever need) assisted by a tiny 96 x 16 blue OLED display, 6 push-buttons (including the on/reset and the off buttons), an Ethernet connector, a USB host port, a USB device port, a USB debugger/programmer port (ICDI), a micro-SD card connector, a speaker, power supply, JTAG, two LEDs and probably more that I am overlooking now; and two motor drivers. Thanks to the battery holders (with batteries) on the bottom of the board the whole thing is pretty heavy and the rubber “tires” prevent sliding it off your desk when you hook the board up to a computer with a USB cable that wants to unwind the wrong way around.

A special wireless expansion port is available too on which you can plug a CC1101EM sub-1 GHz transceiver, which will get you an 868 or 915 MHz radio link. The James Bond part of this setup is a third kit from TI, the eZ430-Chronos based on the CC430F6137 sub-1 GHz RF SoC. This is a combination of a biggish but stylish black watch with a large character display and a USB access point for your PC. Once connected you can control your PC with the watch, although it takes some exercise to do it properly. But... you can also use the watch to control the Evalbot! An integrated accelerometer lets you influence the driving direction of the robot by tilting and rotating the watch. Cool huh? The watch in itself is actually a dev kit and you can reprogram it with your own application.



Programming the dev kits is done with Code Composer Studio 4, the Eclipse-based dev environment from TI. A license file is included with the Evalbot kit, but what exactly this enables is not clear to me. I did read something somewhere about code sizes & limits, but I forgot where. Anyway, all the source code for the Chronos controlled Evalbot is available, it compiles without warnings and errors and programs fine. This really is a fine (but strange) development kit.

Become a beta tester and win

It is contest time. I allready mentioned the Luminary, sorry, I mean Stellaris ARM contest from Texas Instruments together with Circuit Cellar and a week later the LPCXpresso ARM contest by NXP. Now it is Freescale who organises a contest. OK, this is not a very difficult contest and you don't have to design anything, but you can win some smart prizes.

To participate you only have to enter the CodeWarrior Development Studio 10.0 beta test program. Free access to the beta release, including full documentation and task-based videos are available for a limited time at www.freescale.com/cwmcu10. CodeWarrior integrates the development tools for the RS08, HCS08 and ColdFire architectures into a single product based on the Eclipse open development platform. Since this is a beta release, it cannot be used for the development of production products. However, you are encouraged to explore the functionality of this new development environment.

To recognize your participation, on April 12, 2010 Freescale will be drawing names from the pool of beta testers for three exciting prize packages:

- Canon Rebel digital single-lens reflex (SLR) camera
- Wii game console by Nintendo
- Garmin handheld GPS

So, go get that 500+ MB download and win that camera!

P.S. You have to submit feedback through a Freescale Service Request to really enter. Alternatively, participants may send an email with name, address (including zip code), home and work telephone numbers (including area codes) to r63076@freescale.com.

Will the new Bill Gates please stand up?

Circuit Cellar together with Texas Instruments have launched a design contest around the Stellaris LM3S9B96 microcontroller. This 100 pin controller is based on a 32-bit ARM Cortex–M3 core with 256 KB flash memory, 96 KB RAM and it sports many interesting features like CAN, USB 2.0 OTG/Host/Device, 10/100 Ethernet MAC and PHY, I2C, I2S, SSI, UART, PWM, ADC and some other peripherals. Although this is more or less what you would expect from a modern 32-bit microcontroller, it is not all: the device also has a built-in library with almost 400 functions to access its peripherals. This BIOS (Basic Input Output System) provides a nice hardware abstraction layer for almost all of the registers and makes life of the programmer much easier.

To top thing off, the device also has a built in real time operating system (RTOS)! According to the datasheet the controller has a copy of SafeRTOS inside, a secure version of FreeRTOS edited by Wittenstein. Unfortunately, the datasheet isn’t very verbose about it, but it is there.

Now what do you call a processor with peripherals, a BIOS and an operating system? A computer! Indeed, this microcontroller is pretty much like a computer on a chip (CoC) and the only thing missing is a graphical interface, but that is probably just a matter of time and/or pin count.

Are we entering a new era of microcontrollers? Will this be the new standard architecture for the next generation of microcontrollers? What about code portability? Will the user get access to the source code of the built-in BIOS and RTOS? Will ARM, TI & Wittenstein be the next Intel, AMD and Microsoft?

At the end of 2008 I assisted at an ARM conference in Paris. The buzz word then was "code portability". If only everybody would be using ARM-based processors, then code would be easily portable from one device to another. Luminary, the developper and former owner of the Stellaris processors, was present too. But is the BIOS & RTOS they now put in their devices good for code portability? Will other ARM-based microcontroller manufacturers too integrate a compatible BIOS & RTOS in their devices or provide compatible libraries? Or are we going to have to deal with tens of different BIOS-es and RTOS-es in the future, supported by code bloating tests to figure out what the heck the platform actually used is capable off?

Devices will get bigger and will integrate more and more. Within a couple of years they will be as powerfull as a modern PC is now, with built-in BIOS and OS. This all smells so much of Microsoft and the OS wars from the past years.

NOOOOOOOoooo!!!!!

Please, not again!

And the winner is…

Last week I did a small survey of microcontroller preferences. Although I had an idea what to expect, there were some surprises in the responses. First of all I received much more reactions than I had hoped for. I would like to say thank you very much to all of you who took the time and effort to reply to this survey! The people that posted a reply (in English!) directly to the blog will find it added to my original post. Those that sent me an email, well, I am very sorry, I am not going to add them all to this blog as there were way, way too many. However, I did spend a few hours reading all the messages and a summary follows here.
What we all want to know now is of course: who won?

But before I will tell you, you will have to read through the following advertisement.

Just joking: the winner is… AVR! Yes, the AVRs received 43% of the votes, while the PIC family lagged behind with 35%. The rest of the votes went to other families of which the MSP430 and the Propeller were mentioned quite often. 8051/2 clones are also reasonably popular.

The main reason for the AVR domination was the available tools. Although free tools exist for many microcontrollers, BASCOM for AVR was mentioned several times and also Arduino. Now this survey originated at Elektor and was read mostly by Elektor readers, so it is biased as Elektor has published quite some projects using BASCOM-AVR, but in general it was felt that the free tools (BASCOM is free only for small executables) for AVR are better than those for PIC. Also the AVR seems to be more easily available and cheaper than a PIC (even more so since Microchip restricted their sampling program), especially important outside the US and Western Europe.

In favour of the PIC was the abundant documentation, examples and free libraries. It is true that Microchip puts a lot of effort in that. On a pure technical level, some people felt that the PIC is less sensitive to noise than the AVR.

Other processors were of course mentioned, but as the survey mainly spoke about PIC and AVR, most people restricted themselves to these two families. However, as stated by several people, if the MSP430 would exist in more DIP packages (only the smallest ones are available in DIP packages), they would definitely prefer it over both PIC and AVR. Surprisingly to me the Propeller from Parallax was mentioned a few times too. Personally I think of this processor more as a sort of freak processor and I would not easily invest time and money in it. Maybe the future proves me wrong, what do I know?

Several people liked the Stellaris, now from TI, others love Freescale.

What is very clear from all the responses and which didn’t surprise me much: architectural reasons clearly do not dominate the choice of a controller family. Once people have learned to use a certain microcontroller family and have invested in tools, they are not very likely to switch to another family from another manufacturer just for the fun of it.

So, my next question is: what does it take to make you switch to a competing microcontroller?