CY_U3P_USB_GS_INTERFACE & CY_U3P_USB_GS_ENDPOINT are USB standard requests about the Interface and Endpoint respectively (Refer to the USB 2.0 Spec). So here 0x81 and 0x82 are bmrequest. But endpoint 0X81 used in fx3 slavefifo FW example is the EP number over which communication happen. So don't confuse CY_U3P_USB_GS_INTERFACE with endpoint 0X81 used in slavefifo example.
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