You can refer to the following App Note:
For getting used to GPIF Designer, you can refer:
FX3_SDK_Installation_path\EZ-USB FX3 SDK\1.3\doc\GPIFII_Designer
The above path is accessed after you install FX3 SDK from the below link:
thanks for reply.i have read them, but i still don't konw how to do at the mcu side.
AN87216 has both Master and Slave firmwares. One FX3 acts as a Master and other slave. So, you can refer to the GPIF state machine implementations in both the cases and see how the reads and writes are managed.