The AM261x LaunchPad supports a fast serial interface by terminating the SoC signals to a 10-pin header. The interface has two lines of data and a clock line for both the receive and transmit signals. The 10-pin header is connected to the 3.3V System voltage supply. AM261x internal pinmux can be used to select between FSI signals and other functionality of the associated pins. After that there is 2:1 mux that select between FSI signals and OSPI signals, from FSI signals are routed to the 10-pin header.

Figure 2-21 FSI 10-Pin Header