On Gumstix

The Gumstix is a series of small computers, with the OMAP35xx system-on-chip connected to periferals such as TPS65950 and a micro-SD card. For all these basic details, see the Gumstix home page.

I have an Overo Water COM and a Tobi expansion board. This provides a number of useful connections. There are three different USB connnections, two 1/8 inch jacks for audio in and out, an HDMI connector for a monitor, a small coaxial socket for power input and the RJ45 for Ethernet.

Then there are 40 pins that can be used to connect other things.

The device runs Linux, I have tried several variations. There is the desktop version, with a nice Angstrom GUI on the screen, with keyboard and mouse hooked up in the On-The-Go USB port, but there is no room for a compiler or anything interesting -- although it is possible to cross-compile, there is the advantage of having the compiler on-board, as I only have one of these so far. Should I buy more of them, there will be more use for the advanced GUI on some units and I can run the compiler on others, much like one of the 16 Picotuxes have been used mostly for proofs of concepts and tests while others have been made part of larger, complete instruments.

There is a bunch of documentation scattered around the net, there is some info in the gumstix wiki, but there are other details that are not all within the scope of that. I'll be detailing the particular hardware and software I'm dealing with here. There are several things that need to go together to make use of the various periferals and features on this system.


The i2c-3 bus is available on the 40-pin header. This, like the other IO lines here, runs at 1.8 V, so a level-translator to 3.3V and a DS1621 are connected. This does work. The DS1621 is great for making test connections to various i2c busses. If it works, chances are anything else should work as well.

ADC inputs

PWM0 and PWM1

serial port

Other PWMs, SPI, GPIO bits

On-board connection: sound-input/output

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