Gravitar

Atari · 1982

by Daniel Ferrer

Details

Original hardware

Atari 6502, AVG, 2× POKEY

Romset

roms/gravitar.zip

Controls

Pull the stick down for a coin and START (button 4 still inserts a coin and then starts). The stick turns, and up thrusts. Button 1 fires, button 2 thrusts, button 3 is the shield and tractor beam. TURN WITH BUTTONS (options screen): buttons 1 and 2 turn, 3 thrusts, 4 fires, the stick up is the shield. On the web: Z, X, C, V and the arrow keys.

Analog controls

–

Last update

2026-11-08

Changelog

1. v1.12026-11-08
   • A second control layout, TURN WITH BUTTONS on the options screen: buttons 1 and 2 turn left and right, 3 thrusts, 4 fires, and the stick up is the shield and tractor beam.
   • Coin and start on the stick: pull it down for a coin and then START, in either layout.
   • The options screen's CONTROLS page also says what the stick does.
   • The romset can live in any folder of the card. The game looks in .roms/, then roms/, then searches the whole card, and remembers where it found it (.conf/<romset>.loc), so the next start goes straight there; if it is moved, it is searched for again.
   • Settings go in .conf/ and romsets in .roms/: the UVMC2's menu hides folders whose name starts with a dot, so the card shows only the games. A card set up before keeps everything: the old config/ and roms/ are still read, and nothing is written to them any more.
   • Without the romset on the card the screen says ROM FILE NOT FOUND and the name of the zip it wants.
2. v1.02026-11-05
   • First release.
   • Sound through the jack: its two POKEYs emulated, the level measured against MAME on its own POKEY writes replayed at the same instants (the tones match; the explosions' noise comes out about 6 dB softer).
   • The shots show: they are the vector generator's dots, which were not drawn.
   • Still screens no longer blink: the board runs at 61.5 Hz, and once every ~40 frames the game started a second picture inside one of ours, drawn twice. One picture a frame now, as the PiTrex port meant to.
   • Button 4 inserts a coin and starts; fire, thrust and the shield on buttons 1 to 3, the stick turns.
   • The cabinet's switches as MAME ships them: four lives. They read three.
   • The picture is MAME's 420 x 400 window, fitted to the screen.
   • Starts at 50 Hz: the beam takes 16-18 ms to draw a frame, more than 60 Hz leaves.
   • An options screen at start, after the Vectrex Studio intro: screen vertical or horizontal, refresh, brightness, controls (the buttons can be remapped, and the choice is saved) and calibration.