RCA Studio II Emulator

Instructions

RCA STUDIO II EMULATOR This is a full emulation of the RCA Studio II, a home console RCA released in January 1977. Not a remake of the games, but the actual machine, running the actual 1976 ROM. Everything the real hardware did, the blocks do. WHAT'S EMULATED - CDP1802 CPU, the complete instruction set, all 256 opcodes, with cycle counting - CDP1861 "Pixie" video chip, where the 64x32 display is generated by DMA stealing bus cycles from the CPU, 128 scanlines of 8 bytes each, exactly as the real chip did - Interrupts and display sync, including the EF1 timing the BIOS depends on - Both 10-key keypads, through the port-2 latch and EF3/EF4 lines - Sound, the beeper gated by the CPU's Q flip-flop - The original RCA BIOS, plus 18 cartridges and 2 homebrew programs CONTROLS When it first starts up, click on the screen once. Scratch won't send key presses to the project until you do, so the keyboard will seem dead otherwise. Click the on-screen buttons, or use the keyboard: Player 1 Player 2 1 2 3 7 8 9 Q W E Y U I A S D G H J X B RS resets the console. CT swaps cartridges: click it, then pick a number from the list. Most Studio II games use the keypad for absolute positioning. Pressing a number moves you to that position rather than nudging you along. In the games that scroll or have paddles, 2 and 8 move up and down. BUILT-IN GAMES (cartridge 0) 1 Doodle. Draw on the screen with the keypad. 2 Pattern. Draw with keypad, then press 0 to make pattern 3 Bowling. 4 Freeway. Cross the traffic. 2 and 8 move you. 5 Math. Addition drills. CARTRIDGES Load one with CT, wait a second or two for it to boot, then press the start key listed below. 1 Concentration Match (Europe) start with 1 2 Demonstration Cartridge start with 1 3 Speedway + Tag (Europe) start with 1 4 Spacewar start with 3 5 Tennis / Squash start with 2 6 Baseball start with 0 7 Speedway / Tag start with 1 8 Blackjack start with 2 9 TV Bingo start with 1 10 Biorhythm start with 0 11 Computer Quiz start with 1 12 Fun With Numbers start with 1 13 Gunfighter / Moonship Battle start with 1 14 Math Fun start with 1 15 Bingo start with 1 16 Concentration Match start with 1 17 Star Wars start with 1 18 Pinball start with 2 19 DOOM (homebrew) starts on its own 20 Life (homebrew) starts on its own Tennis is a good one to try first. Player 1's paddle is on the left, player 2's on the right, and 2 and 8 move them. HOMEBREW Cartridges 19 and 20 aren't real Studio II releases. I wrote them in native 1802 machine code for this emulator, each with its own interrupt handler driving the video chip. 19, DOOM. A raycast first-person maze, about 340 bytes of code. 16 rays across the 64-pixel view, an 8x8 grid map, 64 facing directions. 2 forward 4 turn left 8 back 6 turn right 20, Conway's Game of Life. A 16x16 toroidal grid drawn as 4x2 blocks, seeded from a shift register. Press 1 to reseed with a new random soup. A generation takes about 23 console frames, so the screen updates in bands rather than all at once. Both are slow. Each frame runs tens of thousands of CPU instructions, so these two in particular are much better in TurboWarp. SPEED Scratch can't quite run this at full speed. It's doing about 25,000 blocks per emulated frame, sixty times a second. It's playable here, but for true speed load it into TurboWarp, which compiles the blocks and runs the machine at its real 1.78 MHz. The project paces itself off the clock, so it stays at the correct speed either way rather than running fast when there's headroom. WHY THIS IS UNUSUAL There are Studio II games recreated in Scratch. As far as I've been able to find, this is the only actual emulator of the console itself, meaning it runs the real ROM images rather than reimplementing the games, and any Studio II software would run on it.