Homebuilt Beagle Board serial cable

As I stated on Saturday, most of my Beagle Board parts arrived, and even though I have presentations to work on for conferences two weeks from now, I couldn’t resist at least setting things up. I mean, how hard could it be?

As background, I administer the Meld embedded Linux community and work as a technical writer at MontaVista Software. I will be giving presentations on community and collaborative development at the Embedded Linux Conference and Linux Collaboration Summit in April in San Francisco. I will also be demonstrating several interesting projects running on the Beagle Board at ELC, including MontaVista’s new MID platform. That is, if I can get everything working!

As it turns out, bringing up the Beagle was both easier and harder than I expected. The board itself does not come with any cables or connectors, but there are some excellent resources in the Beagle community, including a very valuable shopping list for those of us who don’t know what we are doing.

I ordered the following parts, shown with source and prices in $US (not including tax and shipping). I’m also not including things I had around the house already, like network cables.

part price source
Beagle Board system-on-chip, rev. B7 149.00 DigiKey
4GB SD Card with RevB Angstrom Demo 15.00 SpecialComputing
USB SDHC Reader 9.00 SpecialComputing
IDC10 DB9M Bulkhead Cable 5.00 SpecialComputing
USB Ethernet Hub Kit 49.00 SpecialComputing
5mm Power USB Cable 8.00 SpecialComputing
USB Mini-A OTG Cable (6-in) 9.00 SpecialComputing
HDMI DVI-D Male Cable (6-ft) 11.00 SpecialComputing
BELKIN F5D7050 USB 802.11g Adapter 24.99 NewEgg
Link Depot USB-to-PS2 Converter 3.99 NewEgg
OCZ Speed 150x 2GB SD card 10.99 NewEgg

The total cost of the extra parts was $145.97, almost exactly the same as the board itself. I highly recommend all of these providers (DigiKey, Special Computing, and NewEgg), as they all shipped the right products immediately and very well-packaged, and there were no financial snafus.

Astute embedded developers will notice one missing crucial item: a null-modem serial cable to connect the board to my PC and run a console. The Beagle has an IDC10 (aka Everex) pinset as its serial interface. As an old-school geek, I could have sworn I had a ton of these in a box somewhere. However, among the dead floppy drives, network cables with broken ends, old mice, parallel and IDE cables, PCI modems, etc I did not locate a serial cable with female ends, let alone a null-modem.

I should have purchased the IDC10-to-DB9F cable directly from DigiKey for $16, or at least the DB9F-DB9F null-modem cable from Special for a whopping $4. But I didn’t. So I wired one up, using some old phone wire, a serial-to-PS2 adapter that happened to have a female end, and the clipped-off DB9F end from a serial mouse. It’s ugly, but it works, and the Beagle requires only two lines, xmit and recv on pins 3 and 5. Remember to reverse them to make a null-modem. I found the correct pinout thanks to the active Beagle community.

No, I didn’t actually use duct tape, but I have some here just in case.

I also did not opt for the fancy acrylic case offered by Special Computing. Instead, my 11-year-old son made me a fantastic “case” out of Legos that looks (vaguely) like a dog. I will bring it to the conference. UPDATE 4/14/09: I brought it to the conference, and it was very well received.

Note that there is also an active discussion on the Beagle board and other TI reference boards on Meld.