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Undo revision 86635 by [[Special:Contributions/EBO|EBO]] ([[User talk:EBO|talk]])
The MegaROM is a low-cost replacement for a standard ROMBoard, but rather than using an array of 16 kb EPROMs as traditional ROMBoards use, the MegaROM uses a single 8x128k (1Mbit) or 8x256k (2Mbit) EPROM (or Flash EPROM) divided into 16 kb blocks. This not only reduces the size of the device significantly, but due to the fact that 16 kb EPROMs are a dying breed, it is much easier and cheaper to find a single 8x256k EPROM than buy sixteen 16 kb EPROMs.
The complete hardware of the MegaROM was developped developed by [[User:Bryce|Bryce]] of [[FutureSoft]]. The original idea came from discussions with [[TFM]] of [[FutureSoft]]. The main goals being that it would offer up to 16 ROM positions, be very low cost and be a single-sided PCB design so that it could be easily built by most electronic hobbyists. It is the predecessor of the Flash ROM based [[MegaFlash]]. If you have any further questions regarding this project contact [[User:Bryce|Bryce]] through the Wiki Forum.
== Warning / Disclaimer ==
Using your favourite EPROM Programmer, you can burn the ROM images to the locations shown below. You can either do this ROM for ROM or compile one single ROM file to burn in one go. You should set the EPROM programmer to only write to the area required, in case you want to add additional ROMs later, any unwritten area will be regarded as empty by the CPC. Below you can see the memory allocation for each virtual ROM within the EPROM. This file is also available below in PDF Format.
A full list of available ROMs can be found [[ROM|here]].
The MegaROM is compatible with all 464, 664, 6128, 464+ and 6128+ and can be used to host standard ROM images such as [[AMSDOS]], [[BCPL]], [[FutureOS]], [[MAXAM]], [[Protext]], [[QuickCMD]], [[Utopia]], [[VDOS]], [[XD-DOS]]. A full list of available ROMs can be found [[ROM|here]].
CPC Specific Limitations: * CPC464/664 - The 464 and 664 only scan and initialise ROMs 7 to 0 at start-up. ROMs 15 to 8 are only accessable if manually initialised.* CPC6128 - Classic CPC6128 can not overwrite the internal ROM 7 with an external device, to make use of the external ROM 7 the CPC must be modified to allow the internal ROM 7 to be disabled (eg: By adding a switch to the internal ROMs Chip Enable pin) The MegaROM fully decodes the Address and Data buses, so it should not clash with any other official expansions installed in parallel or plus cartridges. However, adding two or more ROMBoards to a CPC in Parallel will cause crashes in some circumstances.
== Resources ==
