Changes
ROM
,[[Image:Rom_Expander.jpg|right|thumb|320px|A conventional ROMBoard for six expansion ROMs]]
== What Exactly are Internal and Expansion ROMs ==
== The Hardware ==
[[Image:MegaFlash_Final.jpg|thumb|280px|right|The MegaFlash - A 32 Position combined ROMBoard]] The CPC can choose which ROM chip is associated with the 16K area starting at &C000. This is usually the reserved for the contents of the screen (RAM), but the address range is shared with ROM Memory. On start up, the CPC checks whether any ROMs are installed. The CPC464 only checks for ROMs in positions 7-0, but the 6128 checks for ROMs in positions 15-0. The ROMs are scanned in the reverse order starting from 7 or 15 depending on the CPC type. If a ROM is present, the CPC reads what commands the ROM offers and saves them in a table in RAM.
== Reserved ROM Numbers ==
== Lower ROMs ==
[[Image:FO.DOS Cartridge (photo from mic-cpcrulez).jpg|thumb|280px|right|FO-DOS - A Lower ROM expansion used to replace the internal Firmware]]
A further ROM is present inside the CPC. This Firmware ROM is in all CPCs, but is mapped to a different area of memory and also doesn't have a ROM Number. It's also possible to overwrite this ROM externally, however this can't be done with a standard ROMBoard, only with Lower ROM expansion such as [[FO-DOS|FO-DOS]]
== Available ROMs ==
