Over at the GigaMegaBlog, they have another fantastic Beaglebone 101 tutorial. They run through everything you need to know to get SPI output with a Beaglebone.
I’ve been experimenting with SPI and I2C on my Beaglebone lately. When I first tried using them at the beginning of the year, I found they required a level of Linux Kung Fu that was beyond me. However, both of these protocols are now supported from “userland” applications in both Angstrom and Ubuntu. A Google search turns up plentyofworkingexamples for SPI and I2C on the Beaglebone, along with some more advancedprojects. I think the water’s safe safe for the rest of us.
I’m going to begin with SPI. Ultimately I’ll be using a graphical LCD, specifically anAdafruit ST7565-based LCD, but in this article I’m going to use a simpler character LCD backpack, also from Adafruit, that uses the popular and well-documented 74HC595 SPI chip.
From the fine people who have brought us the Beagle Board, we now have a smaller, lighter, but powerful single board linux computer, Beagle Bone! We like this move to a more compact and integrated SBC. For example, there is onboard Ethernet and USB host, as well as a USB client interface (a FTDI chip for shell access). It even comes preloaded with Angstrom Linux on the 4 GB microSD card!