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Black Box with a View
Pages: 1, 2, 3

Appendix A

Installing the development tools

This appendix describes how to install the mspgcc suite of tools for the MSP430 microcontroller. See http://mspgcc.sourceforge.net/ to download the tools and additional documentation.

Note that some MSP430 development boards (such as the Texas Instruments MSP430 Development Tool, model MSP-FET430X140) power themselves solely through the PC parallel port, via the JTAG adapter.

If you are using such a board and your uploaded program does not run, you may need to give the --no-close option to the pyJTAG tool. Here is an example.

$ msp430-jtag --no-close -epvr hello-world.elf

You may have to type msp430-jtag.py instead of msp430-jtag, depending on how you installed pyJTAG. The --no-close option is a very recent feature at the time of this writing, so you may need to download and build pyJTAG from source if your development hardware requires it.

In any case, you will need a free parallel port in order to use pyJTAG.

Windows installation

Installing mspgcc under Windows is very simple. Download the latest mspgcc-win32 package (mspgcc-20060119.exe), run the executable file, and follow the prompts. According to the mspgcc manual (see the "Windows installation" section), the installer works with Windows 98, ME, NT, 2000, and XP.

Linux installation

Make sure that the parallel port you are planning to use with pyJTAG is not already in use by a daemon process (such as lpd). The pyJTAG utility also requires the ppdev kernel module, unless you compiled it otherwise.

If you want to run pyJTAG as an ordinary user, you can make the port (/dev/parport0 by default) world-readable and writable. Alternatively, add your username to the port's group in /etc/group, then log out and back in again for the change to take effect. The group should also be able to read to and write from the port for this to work.

Sourceforge has source code tar archives and RPM packages of mspgcc. In order to run a recent version, however, it is best to build mspgcc by checking out some of the components from CVS.

The "Building mspgcc from source code" section of the mspgcc manual and the mikrocontroller site both provide detailed building instructions for mspgcc. The discussion here follows the latter set of directions. Note that it is not necessary to build gdb (the GNU debugger) or the gdbproxy (which enables gdb to debug MSP430 programs running on an actual target) for these articles.

In order to build mspgcc from source, first make a temporary subdirectory in which you will compile the tools. Your home directory is a good place for this temporary subdirectory. You will also need a working Internet connection. (Broadband is recommended.) You should know the root password to your system and must use a 2.4 or higher series Linux kernel. (A 2.4 series kernel was used to verify the instructions given here).

$ mkdir t
$ cd t

Next, create the binutils and add them to your path.

$ wget ftp://sources.redhat.com/pub/binutils/releases/binutils-2.14.tar.bz2
$ tar xjvf binutils-2.14.tar.bz2
...
$ cd binutils-2.14
$ ./configure --prefix=/usr/local/msp430 --target=msp430
$ make

$ su   #You will be prompted for the root password.
# make install
# exit

$ cd ..
$ export PATH=/usr/local/msp430/bin:$PATH

Now, build the mspgcc compiler. When prompted for the CVS password, just press Enter. Note that the mspgcc numbering does not correspond to the GCC core numbering; mspgcc version 3.3 actually matches GCC core version 3.2.3.

$ wget ftp://gcc.gnu.org/pub/gcc/releases/gcc-3.2.3/gcc-core-3.2.3.tar.bz2     
$ tar xjvf gcc-core-3.2.3.tar.bz2

$ cvs -d:pserver:anonymous@cvs.sourceforge.net:/cvsroot/mspgcc login
$ cvs -z3 -d:pserver:anonymous@cvs.sourceforge.net:/cvsroot/mspgcc co gcc/gcc-3.3
$ cp -r gcc/gcc-3.3/* gcc-3.2.3/

$ cd gcc-3.2.3
$ ./configure --prefix=/usr/local/msp430 --target=msp430
$ make

Now, become the superuser and install the mspgcc compiler. Under some Linux installations, you may have to set the path again (export PATH=/usr/local/msp430/bin:$PATH) every time after becoming the superuser, but this is usually not the case.

$ su
# make install
# exit

$ cd ..

Create the MSP430 libc. If you need to log in to CVS again, you can always do so by reissuing the command cvs -d:pserver:anonymous@cvs.sourceforge.net:/cvsroot/mspgcc login

$ cvs -z3 -d:pserver:anonymous@cvs.sourceforge.net:/cvsroot/mspgcc co msp430-libc

$ cd msp430-libc/src
$ make

$ su
# make install
# exit

$ cd ../..

Finally, build the pyJTAG tool, which you can use to upload your compiled firmware to the target. The tool requires the Python programming language, version 2.2 or later. Most major Linux distributions include Python. Use the command python -V to check your version.

If you want to use something other than your distribution's default Python to run pyJTAG, you can substitute commands such as python2.3 for python. Of course, you need to have the additional Python version installed beforehand. Several different versions of Python can coexist on the system without problems.

$ cvs -z3 -d:pserver:anonymous@cvs.sourceforge.net:/cvsroot/mspgcc co jtag  
$ cvs -z3 -d:pserver:anonymous@cvs.sourceforge.net:/cvsroot/mspgcc co python

$ cd jtag
$ make
$ su

Now you must ensure that your /etc/ld.so.conf contains a line /usr/local/lib. If necessary, edit the file (as root) to add the required line. Note that some Linux distributions (such as Gentoo) generate ld.so.conf from some other file automatically, in which case you will have to change that file instead.

Also make sure that the ldconfig command is in your path before attempting to install the JTAG libraries. Usually, ldconfig is in the /sbin directory.

# export PATH=/sbin:$PATH  # So that "ldconfig" can be found.

# make install 

# cd python
# python setup.py install #You can use "python2.3", etc. instead.
# cd ../..

# cd python  #Note that this is a different "python" directory.
# python setup.py install #Use the exact same "python" command as before.

# chmod 755 msp430-jtag.py

If you are using anything other than python (for example, python2.3), edit msp430-jtag.py to change python in the top line (to python2.3, for instance).

# cp msp430-jtag.py /usr/local/msp430/bin/msp430-jtag

# cd ../..
# rm -Rf t

# exit
$ cd

Add the directory /usr/local/msp430/bin permanently to your path (typically in your .bash_profile).

Appendix B

Installing and handling the hardware

You will need the following components in order to follow the examples in this series of articles:

  • an ordinary PC running Windows or Linux
  • the Olimex easyWeb2 development board
  • a DC power supply (see the following discussion)
  • the Olimex JTAG adapter for the MSP430
  • a straight-through parallel extension cable
  • a null-modem serial cable
  • a free parallel port
  • a free serial port

If you want to substitute another development board for the easyWeb2, see Choosing a Platform for the list of required features. The discussion in this appendix assumes the use of easyWeb2.

The work required to set up the hardware is absolutely minimal, but please read this appendix through to the end if you have little experience working with open circuit boards. The information presented here will help you avoid frustration, and possible damage to the equipment.

An AC adapter (the familiar "power brick") is a simple, reliable, and inexpensive solution for supplying DC power. Many distributors (such as Spark Fun Electronics) will offer you an appropriate adapter when you buy the easyWeb2 development board. This is the safest option if you have any doubts about your source of power.

The serial cable (needed for later articles in this series) needs only the transmit, receive, and ground lines--the additional lines of a full null modem will go unused. This can save you a lot of effort if you build your own cables.

Many embedded devices contain static-sensitive components, which a single careless touch can destroy. The next section describes several basic techniques for avoiding static discharge damage.

It is safest if you turn off all components (including any peripherals attached to the PC) before starting.

Connect the JTAG adapter to the PC's parallel port. (You will almost certainly need an extension cable.) Plug the other end of the cable into the easyWeb2--there is a connector labeled JTAG on the board. Make sure that red stripe on the cable is toward the pin 1 side of this connector. The location of pin 1 is clearly indicated on the board, right beside the JTAG connector. Figure 2 shows the JTAG adapter correctly attached to the easyWeb2.

Finally, attach the AC adapter to the board.

A note on static electricity

Static electricity poses a grave danger to many electronic components. It takes only a gentle touch to pass a charge from your body to the device, potentially causing permanent damage to the system.

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Ideally, you should wear a grounded wrist strap when handling open circuit boards and especially individual components. You should also have a grounded antistatic mat on your work surface. Note that these tools are designed with safety features--grounding yourself with just a plain piece of wire can easily give you a deadly electric shock!

Keep any loose circuit boards in antistatic bags. These bags are often silver in color, but this is not universal. If you have ever upgraded your PC and kept the packaging, you should have some antistatic bags around.

Always fold the open end of the bag and tuck the excess underneath the board so that the weight keeps it folded. Use antistatic foam to line containers that hold unmounted sensitive parts, such as microcontrollers. Put the components on the foam. The black squares on which the 486 and MSP430 chips rest in Figure 1 are made of this material. Note that the chips were placed pin side up in Figure 1 just to take the picture; the correct position for storage is with the pins on the foam.

Antistatic bags are often an acceptable substitute to the antistatic mat and wrist strap. Spread the bag on your work surface, touch the bag to dissipate static, and then place the board fully on the bag. When putting the board down, make sure that your hand makes contact with the bag before any part of the board does. You should also touch the bag on which the device is resting before picking up or otherwise handling the board. Figure 2 shows the easyWeb2 placed on top of an antistatic bag.

One way of dissipating a high static charge is to touch a fully closed metal case of a PC. The machine has to be plugged in, but turning it on is unnecessary. This method of dealing with static, however, requires constant vigilance, because you must remember to discharge yourself frequently. In addition, you still have to follow the directions in the previous paragraph for handling your hardware.

Common sense antistatic precautions are important as well. Use a work surface (such as a wooden board) that does not generate a static charge readily. Wear 100 percent cotton clothing instead of synthetics when working with open circuit boards or unmounted components. Maintain sufficient air humidity, and be aware that walking on carpet can quickly build up a very high static charge.

George Belotsky is a software architect who has done extensive work on high-performance internet servers, as well as hard real-time and embedded systems.


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