Atari 2600/7800 Monitor Cart

By Scott Stilphen

(Originally printed in the May/June 1994 issue #22 of the “2600 Connection” newsletter)

This package includes:

Monitor cartridge (version 2)
250+ spiral-bound manual

$60 (complete)
$58 (you supply 7800 Hat Trick cartridge)
$50 (upgrade from version 1)

Atari 7800 ProSystem
Two keyboard controllers (for programming/debugging)
One or two joysticks (for demo programs)
Some knowledge of 6502 assembly

If you’ve every wanted to create games for the 2600, then read on. The monitor cartridge is actually constructed from the 7800 cartridge, Hat Trick (by Atari). This is the only cartridge that the ROM can be removed from, and replaced with an EPROM (with the 6502 assembly monitor program) and RAM chip installed. The program is basically in 2 parts; a switch on the side of the cartridge configures it (before power-up) for either 2600 or 7800 mode. Both modes provide adequate debugging monitors and utilities, as well as several demos. The RAM chip features a battery back-up for saving programs and has a total programming space of 4K in 2600 mode and 8K in 7800 mode.

The manual is quite thorough and, besides having the complete operating instructions, contains the source code for the monitor, large demo programs, the MagiCard (by CommaVid) color demo, small sample programs to try out, and a section on designing your own games. Harry also sought permission from Atari to include Combat, Space War, and Slot Racers on the cartridge. Full documentation and specifications on the 2600 and 7800 systems is also included. The Monitor cartridge is a little confusing to use at times, mainly due to its sheer size. There are just too many features to cover in this review.
Please keep in mind that this package is not for everyone, and you should have at least a basic understanding of 6502 programming before even considering to purchase it. Every Atari game system prior to the Jaguar and Lynx is based on some variation of the 6502 microprocessor, not to mention at least a dozen non-Atari systems. This is an excellent language to start learning how to program with, and an economical way to “get your feet wet”.

The creator, Harry Dodgson, mentions possible upgrades if a version 3 is ever made: interfaces for other systems, data storage devices, and a PS-2 keyboard. If you find using the keyboard controllers too cumbersome and you don’t want to wait for the next version, it’s possible to do the bulk of the programming on another system, and then use the Monitor cartridge to translate and save the finished program.

Overall, the Monitor cartridge is a great development software package available for Atari 7800 owners. Facing the fact that there will be no other future support for either system, this is the only choice left to us for new software. Who knows – if enough people get involved, we could possibly create our own 2600 shareware/public domain library.

UPDATE: Since this was written, Harry Dodgson produced only 100 copies of the version 2 carts, after which he sold the rights for this to Video 61, who continue to offer copies for sale. No further development was done on this by either Harry or Video 61. The Video 61 version might be slightly different from the original (the manual is no longer spiral-bound, and the rights for the Atari games and source code may no longer be valid).


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