1 Beaglebone Black {#beaglebone} 2 ================ 3 4 The Beaglebone Black is a very maker friendly Board with a huge amount of 5 available I/O Pins. It consists of an Cortex-A8 single core CPU plus two 6 additional microcontroller cores called 'pru' that can be used for realtime 7 tasks. 8 9 The official Beaglebone Black Image runs Debian on a 3.8.13 Kernel. But there 10 are also mainline kernels available, either from Robert C. Nelson or also as 11 part of the upcoming Fedora 22 release. 12 13 The kernel releases from Robert C. Nelson have usually more complete support as 14 not all code is yet commited to mainline kernel, your mileage may vary! 15 16 In Kernel 3.8.13 there is a Capemanager included, a mechanism to load 17 configuration data for devices and extension boards from userland. 18 19 This mechanism does not (yet) exist in Mainline kernels, so for mainline 20 kernels you need to either rely on the pre-delivered devicetree's or you will 21 need to build your own devicetree to support hardware not available by default. 22 23 Revision Support 24 ---------------- 25 Beaglebone Black Rev. B 26 Beaglebone Black Rev. C 27 28 Interface notes 29 --------------- 30 31 **SPI** works fine with 3.8.13 kernels, on Mainline Kernel SPI does currently 32 not work. mraa will activate spi on 3.8.13 if it finds out that spi is not yet 33 configured 34 35 **I2C** works both on 3.8.13 and mainline. i2c is activated if missing for 36 3.8.13 kernels 37 38 Mainline Kernel requires the use of Device-Trees, mraa tries it's best to guess 39 which gpio/serial/i2c/spi is connected where but there is currently no support 40 to manipulate the Device-Tree settings from within mraa. If a device does not 41 work as expected then please check syslog, mraa usually complains with a 42 meaningful message when it is unable to initialize the device. 43 44 It will also tell you which overlay for SPI/COM/I2C/PWM it tries to load, on 45 some older Debian distributions (or heaven forbid, on Angstrm) you may need to 46 install thoses overlays to /lib/firmware 47 48 Capes and further documentation 49 ------------------------------- 50 51 Correctly configuring i2c/spi/serial can get a little challenging as some pins 52 have double functionality or are not available at all because hdmi is enabled. 53 When something does not work as expected make sure to first check the syslog, 54 then check the Beaglebone documentation. Some pointers for good descriptions 55 are: 56 57 http://elinux.org/BeagleBone_Black_Enable_SPIDEV 58 http://elinux.org/Interfacing_with_I2C_Devices 59 60 When working with mainline kernels take every hit you have on google with a 61 grain of salt, a lot of documentation is based on 3.8 and older kernels. Using 62 mainline kernels can be very rewarding, but at least at time of writing also 63 can have some nasty 64 pitfalls. 65 66 Pin Mapping 67 ----------- 68 69 mraa will take into account if you have hdmi cape or mmc enabled and will show 70 you the gpio's available for your given configuration. 71 72 To see the pin mapping use the command: 73 74 $ sudo mraa-gpio list 75
