BeagleBone: Creative Projects for Hobbyists

Device Tree / advanced – adding DT overlay to run a custom cape

BeagleBone Black introduced the idea of Device Tree overlays that provide even more functionality to DT by modifying the tree in user space, typified in our prior example. With DT overlay, there is no need to reboot.

We saw in our earlier section on sysfs usage the directory/extension .capemgr, which refers to cape manager. The BeagleBone kernel uses cape manager as a way to provide dynamic loading and unloading of device tree fragments both at compile time and from user space after the device has booted. We will demonstrate this again here; except this time, we will use DT to enable a custom cape, one which delivers audio I/O functionality to the BBB.

Getting ready

In addition to your ...