Changes

Jump to: navigation, search

LowerROM

869 bytes added, 11:58, 12 November 2012
[[Image:LR2.png|thumb|380px|right|The LowerROM must be connected between the CPC and any ROMBoard being used]]
 
 
 
 
 
== The Circuit ==
Schematic diagram [[Image:LowerROM_Sch.png|600px|center]]  The LowerROM Board has been made to come laterbe as simple and low cost as possible.As can been seen from the schematic diagram above, the circuit contains no address decoding circuitry.The LowerROM Board simply holds ROMDIS high at all times. However, the ROMDIS on the 50 way connection lead is not connected to the CPCs ROMDIS, rather it is used to disable the LowerROM Boards EPROM, allowing standard ROMBoards to still function as normal. The disadvantage of using this method, is that on a CPC+ ROM 7 and the entire cartridge contents are disabled when the LowerROM Board is connected, which means that the standard (non-patched) Plus OS can not be used on this device and without adding ROM 7 on an external ROMBoard, the 6128+ loses its ability to use disks.On a classic CPC6128 this is not an issue as ROM 7 is not disabled when ROMDIS is pulled high.
== Using the LowerROM Board ==
The button on the right is a reset switch for the CPC.
 [[Image:LowerROMJumpers.png|thumb|600px|center]]
1,179
edits