What are the interleaved NES ROM images?
Interleaved NES ROM image is a file which contains the ROM data in each even byte, and the VROM data in each odd byte. You will have to write a program to separate such file into ROM and VROM, and then glue them together with a .NES header to produce the .NES file. • What is that “Mirroring” flag? In the real NES/Famicom cartridges, either A10 or A11 line of the address bus can be connected to VRAM. Depending on it, video memory may either contain two screens at addresses $2000/$2400 mirrored at $2800/$2C00 (Vertical Mirroring), or two screens at $2000/$2800 mirrored at $2400/$2C00 (Horizontal Mirroring). The games which only use one screen do not care about the mirroring. The games using two screens require an appropriate mirroring though. Be aware that many bank switches allow to switch mirroring from the program. Other cartridges contain additional VRAM and have both A10 and A11 lines connected. Mirroring has no meaning for such cartridges. • What is the “512-byte Trainer”? The 512-
