Thanks a lot for your help, Aiman!
I have gone through PFL guideline. That is very helpful to use this IP for Flash programming and FPGA configuration.
However, I would like to know whether I can use this PFL ip to access (read/write) unused portion of NAND flash memory with Nios II after NAND Flash programmed. As this is possible for serial configuration devices, but not very sure if the unused portions of the NAND flash memory can be used as general-purpose memory or not.
Attached picture is for serial configuration, not sure if I can access for unused memory with NAND flash by PFL ip.
Regards,
Hung