Gives 448 extra pre-programmed graphics symbols. The ROM contains lower-case letters, bombs, bullets, rockets, tanks, a complete set of invaders graphics and more.
The board also has a spare socket that will accept another 4K of ROM, like the 4K TOOLKIT ROM or 1K/2K RAM, for user-defined graphics.
dk’Tronics and Kayde published several games that required this ROM:
- Asteroids (dk’Tronics)
- Centipede (Kayde)
- Defender (dk’Tronics)
- Peckman (Kayde)
- Space Invaders (Kayde)
Technical
The 4K EPROM is mapped to 2000h-2FFFh, with seven new character sets (of 64 symbols each). 2E00h-2FFFh is mainly filled with FFh and contains a few USR functions for selecting the new character sets. The board can be fitted with 1K or 2K static RAM, or 4K EPROM (mapped to 3000h-3xFFh).
Only 64 symbols can be used at once, preventing display of lower-case letters and numeric digits. Many symbols (like A-Z) are duplicated in several 64-character banks, which is why it claims 448 extra symbols (vs the 512 that could be available).
Kayde 4K ROM
Kayde’s variant is a possibly unlicensed clone of the dk’tronics board. With the exception of a few cosmetic differences to the circuit and replacement of some inverse characters with Pac-Man symbols, it is otherwise identical.
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- SYNC v2 n5 p. 94