1Beaglebone Black {#beaglebone} 2================ 3 4The Beaglebone Black is a very maker friendly Board with a huge amount of 5available I/O Pins. It consists of an Cortex-A8 single core CPU plus two 6additional microcontroller cores called 'pru' that can be used for realtime 7tasks. 8 9The official Beaglebone Black Image runs Debian on a 3.8.13 Kernel. But there 10are also mainline kernels available, either from Robert C. Nelson or also as 11part of the upcoming Fedora 22 release. 12 13The kernel releases from Robert C. Nelson have usually more complete support as 14not all code is yet commited to mainline kernel, your mileage may vary! 15 16In Kernel 3.8.13 there is a Capemanager included, a mechanism to load 17configuration data for devices and extension boards from userland. 18 19This mechanism does not (yet) exist in Mainline kernels, so for mainline 20kernels you need to either rely on the pre-delivered devicetree's or you will 21need to build your own devicetree to support hardware not available by default. 22 23Revision Support 24---------------- 25Beaglebone Black Rev. B 26Beaglebone Black Rev. C 27 28Interface notes 29--------------- 30 31**SPI** works fine with 3.8.13 kernels, on Mainline Kernel SPI does currently 32not work. mraa will activate spi on 3.8.13 if it finds out that spi is not yet 33configured 34 35**I2C** works both on 3.8.13 and mainline. i2c is activated if missing for 363.8.13 kernels 37 38Mainline Kernel requires the use of Device-Trees, mraa tries it's best to guess 39which gpio/serial/i2c/spi is connected where but there is currently no support 40to manipulate the Device-Tree settings from within mraa. If a device does not 41work as expected then please check syslog, mraa usually complains with a 42meaningful message when it is unable to initialize the device. 43 44It will also tell you which overlay for SPI/COM/I2C/PWM it tries to load, on 45some older Debian distributions (or heaven forbid, on Angström) you may need to 46install thoses overlays to /lib/firmware 47 48Capes and further documentation 49------------------------------- 50 51Correctly configuring i2c/spi/serial can get a little challenging as some pins 52have double functionality or are not available at all because hdmi is enabled. 53When something does not work as expected make sure to first check the syslog, 54then check the Beaglebone documentation. Some pointers for good descriptions 55are: 56 57http://elinux.org/BeagleBone_Black_Enable_SPIDEV 58http://elinux.org/Interfacing_with_I2C_Devices 59 60When working with mainline kernels take every hit you have on google with a 61grain of salt, a lot of documentation is based on 3.8 and older kernels. Using 62mainline kernels can be very rewarding, but at least at time of writing also 63can have some nasty 64pitfalls. 65 66Pin Mapping 67----------- 68 69mraa will take into account if you have hdmi cape or mmc enabled and will show 70you the gpio's available for your given configuration. 71 72To see the pin mapping use the command: 73 74$ sudo mraa-gpio list 75