Vic-20 Mega Cart Prototype Project

Project is based on concept that originated during discussions at WOC show in Dec 2006.

This concept became a discussion item on an Internet discussion forum devoted to Vic-20 topics

"Denial" http://sleepingelephant.com/denial

The Multi-cart is intended to allow a user to run multiple Vic-20 ROM images from a single cartridge.

This design builds on original concept to add features and functions

1. Concept

· Allow multiple ROM images to be accessible from single cartridge

· Reduce physical storage requirements of having multiple carts

· Greater portability to take cartridge collection with you when you are on the go

· Reduce number of times a cartridge is inserted & removed from Vic-20

2. Project Features

· Ability to run up to 254 - 8K ROM based Vic-20 Cartridge games or utilities

· Support for 4K, 8K, 12K, & 16K ROM games

· Support for all known ROM images, irrespective of location of ROM image in Vic-20 memory map

· Toggle from game to menu and back to game again via reset button

· RAM expanded mode with additional 32K RAM + 3K in BLK0

- 28,159 bytes directly available to Basic (3,583 core memory + 24,575 expanded)

- plus 8,192 bytes addressable by Basic for storage of variables, arrays, etc.

- plus 3,072 bytes addressable by Basic for storage of variables, arrays, etc. (BLK0)

- plus 1,024 bytes addressable by Basic for storage of variables, arrays , etc (IO2)

· Ability to switch to unexpanded Vic-20 Basic mode without removal of cartridge

· System reset via software control or push button switch 

· Bank switching between RAM & ROM

· Expanded RAM may remain hidden from kernel on start up and enabled via software control – no video memory address change from defaults

· Software controlled write inhibit logic for R/W line on expansion RAM - no clumsy switches

· 200+ Games & Utilities currently loaded and fully functional

3. Menu System

· Advanced beyond preliminary menu

· New Custom character set

· New Custom Mega-Cart logo

· Utility cartridges – Programmers Aid / Super Expander / Vic-Mon able to use multiple memory configurations and have these ROM images work in combination

· Multiple memory configurations possible via menu selection

· Auto start for all ROM images which were previously not auto start

· All games categorized by:

o Publisher

o Game Category (multiple choices i.e. Shoot ‘em, Adventure, Maze, etc)

o Released or hacked – Yes / No / All

o Arcade – Yes / No / All

o Paddles – Yes / No / All

o Favorites – Yes / No / All

· Game / Utility selections may be limited in display menu based on above selections

· Menu favorites selection stored to NVRAM and retained when power or computer is off

· Addition of “Easter Egg”

· Addition of custom games developed by Denial forum members

· Single cartridge for both PAL & NTSC versions of all known Vic-20 games/utilities cartridges

4. Credits

Hardware Design Menu Software Music

Brian Lyons Nicola Di Battista Anders Carlsson

Other Credits (testing / software / concepts / etc)

Anders Carlsson Brent Santin Brian Lyons

Francois Leveille Glen Richards Leif Bloomquist

Jeffrey Daniels Leo Laflamme Mark G.

Mat Allen Nicola Di Battista Robin Harbon

5. Next steps

· Continued testing for new menu features & functions

· Prototype board #2 under construction

· Plan for early Fall 2007 limited production run of circuit boards & assembly of hardware for Denial forum members

· Production run of this project is intended as parts cost recovery (zero profit venture) for Denial forum members

Updates may be found on Denial – http://sleepingelephant.com/denial or

Hardware project page http://www.6502dude.com/cbm/vic20/multicart/