Change FLASH memory from M25P to N25Q series
Created by: Daniel
Created by: henrique-silva
M25P is not recommended for new designs since it isn't on Micron's PLP (guaranteed production for 10 years). The producer recommends changing the part to a compatible one in N25Q series. The N25Q series are logically retro-compatible with M25P, so we wouldn't need any firmware changes.
The only difference between them is the product ID, but, as explained in the compatibility document provided by Micron, this number is assigned by JEDEC and must be different for each part number. This only affects us when generating the .mcs file that is programmed into the FLASH by IMPACT, because it reads the memory ID before start programming. This can easily be solved changing the flash part number when generating the mcs file from the bitstream.
Another reason to perform this change is that we can select a 256Mb part from N25Q series. This would allow us to store a backup FPGA firmware inside the FLASH or even a bootloader implementation.