I can not find the flagC and flagd pins of the CYUSB3014 in the datasheet. Can anyone give me some suggestion?
There is no fixed pin mappings for Flags to GPIO pin. You can choose to map a Flag to any of the available GPIO pins in GPIF II Designer tool. However some GPIO pins are reserved and cannot be used as flags. For eg: GPIO 17 is fixed for GPIF Interface CLK, GPIO 0-15 for 16 bit data bus and so on.
Refer Application Note AN65974 http://www.cypress.com/?rID=51581 which explains how to configure flags in FX3.
Small correction: Its GPIO 16 for GPIF clock interface clock and not GPIO 17.