Here you find a PCB I designed for an Atari 2600 VCS 512-in-1 cartridge.
The 512-in-1 Multi Cart PCB
The Multi Cart uses two 1 Megabyte EPROM chips (27C801) which together can hold a total of 512 4KB games. S3 determines which of the two EPROM chips is used while the two 4-bit (16 positions) rotary switches S1 and S2 select one of the 256 games in the selected EPROM. You can also view the schematics.
You can also use 2KB games by putting the 2KB game twice in a 4KB memory block of the EPROM.
The Visio 2002 drawing of the PCB can be downloaded
here. If you don't have Visio you can download
viewer somewhere from Microsoft's website. The Visio drawing can be printed on transparents for etching a double sided PCB.
Don't forget to solder the connections from the front side of the PCB to the backside of the PCB.
I've also saved the drawing as Enhanced Metafile. If you print the .EMF file on transparents, be sure that it is printed at the correct size. The PCB must be 48.3mm by 91.44mm in size. Any other size and the components won't fit.
The assembled PCB front- and back-side
(Note: S3 is replaced by a jumper since only one EPROM is used. There were not enough 4KB PAL games to fill a second EPROM. But there are enough 4KB NTSC games to fill two EPROM's)
The 512-in-1 Multi Cart in action (Now playing: River Raid)
Insert the Multi Cart with the rotary switches towards you.