The process of figuring out the pinmux can be very confusing for a new user. What is described here is an attempt to identify the information from different sources and connect them to determine a pinmux setting. There are four documents that contain relevant information. They are as follows:
BeagleBone SRM: This describes the signals from the SoC that are exposed on the expansion connectors, P8 and P9. Most users will start here to identify the pins they are using.
BeagleBone schematics: While not strictly needed, the schematics can help clarify some signals. Some signals on the BeagleBone are connected together for backward compatibility with older revisions of the board. The schematic along with the SRM will help you identify them.
AM335x datasheet: This is the documentation labeled as the datasheet on the Texas Instruments website. It is a much smaller PDF document than the TRM. Most of the information here is hardware-specific but we need it...