TWiki . WSensornets . DancingEBugs

Dancing E-Bugs: Real-Time Control over Wireless Links

This page is a collection of information about the Dancing E-Bugs project, but primarily it is a quick 'how-to' get the MicroC-OSII environment up and running on an ATMEL ATMega128 device (or any other capable ATMEL), under Windows.

Software required, and where to get it

uC/OS-II sourcecode and 'port' files

The uC/OS-II sourcecode is available on the CD that comes with MicroC/OS-II : the real-time kernel by Jean Labrosse (search for it at the library). I used version 2.60, which is the minimum I would recommend (the CD also has an older version, which has a few substantial differences.)

You can also try downloading the latest version from http://www.micrium.com/products/rtos/kernel/rtos.html, though I haven't tried it and do not know what the differences are.

The 'port' files customize the OS to run on a particular hardware (the book, for instance, is targeted towards desktop Intel processors). They are also available at the Micrium website, in the ports section at http://www.micrium.com/atmel/AVR.html. I used the port by Julius Luukko: you'll need one for the GNU GCC Compiler.

AVR Studio 4

This is not strictly necessary, it just provides a GUI for the compiler and the programmer, as well as a (somewhat dodgy) text editor for writing C / Assembly. It is available for free from the Atmel Website, after registration, and is worth having.

WINAVR Source Files

WINAVR is a collection of libraries tools for writing ATMEL AVR software in Windows, including the GCC compiler. You can use it directly from the command line after adding some variables to the Windows PATH variable (for masochists) or you can just point AVR Studio to it's location, and let AVR Studio handle producing make files and linking to headers etc. Get it at http://winavr.sourceforge.net.

Notepad++

This is completely unnecessary, but at the same time essential! :D The built in text editor in AVR Studio is awful, especially for editing large text files. If you want something a little bit more upmarket, get a copy of this open source text editor, or if you've already got a favourite, use that! http://notepad-plus.sourceforge.net/.

David's eBugs Project Sources

They are here. For further details check DavidMcKechnie's thesis report.

Hardware Required

Development board

If you're reading this, I imagine you've already got a project so there isn't much to put here. A few thoughts if you're designing a PCB:

Go USB, not serial! If you need a PC interface and you don't have a JTAG-ICE or something (i.e.: you are using an In-System or Flash Programming method), put a USB -> UART chip on your design instead of an RS232 driver. http://www.ftdichip.com/Products/FT232R.htm. You can still communicate via a virtual serial port if you want, but it makes life easier if you forget your USB-Serial adapter.
Go surface mount! Particularly if you are going to be using the department's PCB router rather than obtain a properly fabricated board, soldering surface mount is easier and more reliable than through hole (you will still need some drill holes for vias, mind you). Stick with 0805 sized components for resistors and small capacitors and you won't have too much trouble (if you've never surface mount soldered before).
Don't be afraid of switchmode power supplies. If you need to drive a motor, boosting the battery voltage up to some predetermined value (i.e. 12V) will make your design more reliable and more consistent as battery voltage drops. Have a look at the National Semiconductor power supply designer (http://www.national.com) : they ship sample components too!
Finally, much of the literature on Atmel ISP (In-System Programming) refers to a 10-wire configuration, but the current crop (11/08) of ISP mk2s use a 6 wire configuration. It's just a reassignment of pins: have a look at http://www.popsci.com.au/diy/article/2008-03/mod-it-incredible-two-headed-avr-programmer.

Programmer

I used an Atmel AVR-ISP mk2 programmer to program the board, but apparently you can do ISP by hacking a level shifting board together yourself (try google, if you like). You can get the programmer from a number of places, mine was from Digikey (http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=ATAVRISP2-ND). Alternatively, a JTAG interface like the AVR JTAGICE would be nice if you're feeling wealthy :D.

Installation and Folder Layout

Install the software wherever you want to. I ended up with
C:\Program Files\Atmel\AVR Tools
and C:\Program Files\Atmel\WinAVR\
... it doesn't really matter. The uC-OS2 folder structure is a little awkward, perhaps. Usually it ends up installed in something like C:\Micrium\uCOS-II\etc etc. I much prefer to keep it with the particular project it's attached to rather than a central location. That way, if I modify any of the #defines they only affect this project. So, I keep
C:\Users\David\AVRProj\ projectname \uCOS-II\SOURCE for the uC-OS2 source files

os_core.c
os_flag.c
os_mbox.c
os_mem.c
os_mutex.c
os_q.c
os_sem.c
os_task.c
os_time.c
ucos_ii.c
ucos_ii.h

and C:\Users\David\AVRProj\ projectname \uCOS-II\ATMega128 for the port files.

avr_isr.h
os_cfg.h
os_cpu.h
os_cpu_a.s (renamed from os_cpu_a.asm)
os_cpu_c.c
os_dbg.c

Creating your project!

In AVR Studio, create a new project. Choose AVR GCC (if you can't see it / use it, you haven't got Win AVR installed somewhere acceptable). Choose the ATMEGA128 from somewhere in the platform list, and click Finish.

Find the folder, and copy all the files mentioned above into it, in some subdirectories as described. Then right click on Source Files in the project structure, and add existing source files. Add everything shown in the image above (uCTest.c is my project name/ initial file, so you won't have that). Do the same for headers. The external dependencies will appear after you compile successfully, depending on what features you use in the ATMEL device.

Then click Project->Configuration Options. Check the device is correct, and set the frequency (it gives you a #define you can use, I think it is F_OSC). Click on Include Directories, and make sure you have all the directories in the image above. Particularly important is the .\ directory: that's the project directory! It seems stupid, but if you don't have this there, you can't refer to header files in the main directory!

If you are using below version 2.7, uncomment as directed in this file.
If you #include string.h, you will remove a lot of warnings from compilation when you run the demo program.

Getting the demo file to run

I don't remember the complete steps, but here's a few hints on getting Julius Luukko's demo program runnning:

You should get a few warnings whenever you compile, but obviously no errors. I remember that getting it to successfully compile was mostly a case of including all the correct directories and setting the project up correctly.
- If you have any compilation errors like ../uCOS-II/SOURCE/os_core.c:1354: error: 'OS_STK_DATA' undeclared (first use in this function) then you will need to find the appropriate #define and enable that feature (in this example, setting #define OS_TASK_CREATE_EXT_EN 1 in os_cfg.h ).
Obviously you need a correctly wired up RS232 interface for this to work. Perhaps verify this using a simple polling application (there's one in the ATMEGA128 datasheet) before trying to get uCOS-2 to run.
You might need to change the USART channel to whichever you are using for RS-232 communication (the ATMEGA128 has dual USART, and you might be looking at the wrong one!
The baud rate calculation will be wrong. Check the ATMEL datasheet to find out how to set it right based on the F_OSC define (i.e.: the baud rate is divided from your system clock, so the calculation changes depending on that frequency).
Windows Vista doesn't have a terminal application anymore (how stupid!) Get Poderosa or some other alternative to look at what your project is outputting.
If the baud rate is too low, and the system clock too fast, you will fill up the send buffer very quickly and overflow. You might need to juggle the delay between tasks generating a new random number and the baud rate.
The demo is based on one of the first examples in Jean Labrosse's book, so it's useful to have that open while you are trying to get it going.