Wednesday, July 02, 2008

Serial communication on the EeePC

Whenever I get a new computer, or just anything that is programmable, my first thought is " Will it do RS232 communication ?" That's mainly because I'm working all the time with instruments and micro controller based systems whose main or only form of contact to the outside world is still plain 9600 baud 8N1 RS232 comms...
And for the EeePC the answer is yes.
I connected a fairly standard USB-Serial converter. This device is based on the Prolific 2303 chipset which is very common in most converters these days. The EeePC recognizes and starts it immediately, although this is not immediately obvious. The KDE desktop does not show any sign of activity, and there is no way you can even check it's appearance through the desktop. To be sure it installed, open a console and type 'dmesg'.
[Inline Rant]
(Don't ask me why almost everything on Linux requires typing 5 to 10 letter acronyms for tasks you never even knew existed.. [growisofs, nifd, mozplugger, fstab-sync ??? And these are just a few of the most popular commands.])
[Inline Rant End]
Well, if your USB converter gets recognized it will show up in the last couple of lines of text shown to you. And if so, it's available as /tty/ttyUSB0 (U-S-B-Zero). Now it's time to do something useful. First you will need a communication program, which is not available in the standard EeePC distribution (or 'distro') so you will first have to instal additional repositories: this entry on the eeepc wiki shows how.
Now just start the Applications->System->Synaptic, search for minicom, Cutecom or GTKCom and install it.
I started using minicom, but apart from this being a bit like going back to the eighties (It's a Procomm /Telix for DOS clone..), I could not get it to send what I typed. It did set the Modem Init string, and received all characters I was sending to it, so I assume my USB-Serial adapter works.
So I moved to Cutecom, and this works fine. Cutecom is pretty simple and straightforward, but that's merely a plus if you use it on the rather limited screen of the EeePC.

EeePC is here !

It's obviously the most desirable gadget of the moment. The ASUS EeePC with it's 7" screen, small but complete keyboard and it's beautiful 'Pearl-Shine' white finish. And it's also a real computer. 900Mhz Intel Celeron, 512 MB RAM, 2 Gigabyte flash hard disk, WLAN, Ethernet, VGA output and 3 USB connections make this little box a full fledged PC with capabilities one could only dream of a few years ago. It comes with a Linux OS, and it boots in something like TWENTY seconds. It has many pre-installed apps, like the complete OpenOffice suite, FireFox and Thunderbird, so 90 to 100% of your daily work is covered. And that's what it's for. I think if you buy it as a'multi purpose' desktop PC replacement and expect to work exactly like your WindowsXP machine you're missing the point (and you get rants like "I hate my EeePC"). Nobody complains about his multi media phone not being able to run OpenOffice. That's not what it was designed for.
On the other hand, if you are a geek like me and are tempted by the possibilities of this platform then there is plenty of room for experimenting. But I'll keep the original setup intact because that's really ideal if you want to get some work done in confined spaces like an airplane chair on a low cost flight..