We are using LPC4357 processor. Pin 116 (or P2_1) is used as USB enable for USB1. We are using UBS 1 as mass storage host. Since P2_1 is also GPIO 5 bit 1 we are configuring through the control register SFSP2_1 (0x40086104). The document talks about different modes (Function 0, Function 1 etc.) The sample code we found ( from NXPUSBLib) mentions that we need to configure that pin as Function 4 for USB. However, I am not finding any document that explains what is function 4 (or any other function for that matter). Is there any document that explains different GPIO functions? Is there document that explains different register setting for USB 1 (everything in one place)?