Description
The file below is the PCB Layout for a Multi-Cartridge. This Cartridge allows you to store four 128K games on a single 512K EPROM (27C4001) or Flash IC (29F040). The two DIP switches are used to select the chosen game (as shown below). Because the pinout of 512K EPROMs are slightly different to 512K Flash ICs (A18 moves from pin 31 to pin 1), a jumper needed to be added so that both parts could be used.
Game Locations
When burning / saving the games to the EPROM or Flash, the game files should be stored at the following addresses:
Game 1 = &0 - &1FFFF
Game 2 = &20000 - &3FFFF
Game 3 = &40000 - &5FFFF
Game 4 = &60000 - &7FFFF
Building the Cartridge
The PCB dimensions are identical to an original cartridge and will fit in the original housing. The PCB used should be 1.5mm thick with double-sided 35µm copper.
The three resistors are 10K 1/4W and the capacitor is 100nf.
Components should be mounted on the side with the ground plain.
The Layout file is as always mirror imaged.
Using the Cartridge
I have placed the DIP switches on the outer edge, so that it is possible to change games without removing the cartridge, which might help the contacts last a little longer, but these switches shouldn't be altered while the CPC is running! Turn OFF the CPC before choosing a different game. The normal LKs found on standard cartridges have been removed and the CPCs A17 and A18 aren't connected to the EPROM /Flash at all, so other sizes of EPROM / Flash will not work in this cartridge.
Documents
File:MultiCartridge Layout.pdf - PCB Track Layout
Bryce.