SuperGames Cartridge

From: COPLIN, Nicholas. (
Date: 2000-03-07 03:20:10

Hi All,

The SuperGames cartridge appears to be one of the very few "standard"
Commodore cartridges which can directly use 27xxx EPROMS without adaptors.
Here are the results of some trials I did on the weekend.

U1 and U2 are 28pin ROMS capable of directly accepting 27x64, 27x128 or
27x256 EPROMS.  27x512 EPROMS may be possible if you add an extra 74175

U1 is decoded to address space 8000-9FFF (ROML is CS)
U2 is decoded to address space A000-BFFF (ROMH is CS)

on reset, 74175 latch is reset, thus GAME/EXROM are both low mapping the
16cartridge ROM into memory, bank zero active.

The 74175 latch is accessible for write only at DF00-DFFF, with the
following bit definitions.

Bits 0 & 1 define bank selection 0-3, 0 is power-on default.
Bit 2 is GAME/EXROM control
Bit 3 is like a "write protect" function preventing writes to the 74175

By setting Bit 2, RAM is available again 8000-9FFF and BASIC to A000-BFFF.

A simple hack may be to re-wire Bit 3 as A15 for 27x512 capability or as
individual control for GAME and EXROM for added memory mapping control.

Does any one else have info other carts which take standard 27xxx ROMs?

Enjoy, Nick

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