FC 6502 BASIC brings a classic 1978-style Microsoft BASIC to the Famicom Disk System,

with a full-screen editor and commands for graphics, sprites and sound.
The BASIC interpreter is ported from the official source code of "Microsoft BASIC for 6502 Microprocessor - Version 1.1", which Microsoft released under the MIT License in 2025 (github.com/microsoft/BASIC-M6502).

• Features
  • Full-screen editor (30 x 28 characters) with katakana input and function keys
    - Standard Microsoft BASIC: FOR/NEXT, GOSUB, arrays, strings, floating point, DEF FN ...
  • Graphics: LOCATE, COLOR, palettes, character code read-back (SCR$), PSET (60 x 56 dots)
  • Sprites: 8x8 and 16x16 sprites with position read-back
  • Define your own BG and sprite characters from BASIC (BGDEF / SP8DEF / SP16DEF)
  • Sound: BEEP, music with PLAY (including the Disk System's FM sound channel), sound effects
  • Controller and keyboard input (PAD, INKEY$), frame timing (VSYNC, TIME)
  • Save / load programs on disk, and on cassette tape (CSAVE / CLOAD)
  • About 16 KB for your BASIC program and variables

• What you need
  • Famicom + Disk System (RAM adapter) + Family BASIC keyboard, and a way to write the disk image (e.g. FDSKey), or
  • an emulator that supports the Disk System(the Disk System BIOS is NOT included; please use your own)

• Download contents
• fc6502basic.fds ........ disk image
• Manual (Japanese) .txt.... command reference
• LICENSE.txt .......... license and copyright notices

• License
  • The BASIC interpreter derived from Microsoft's source: MIT License, Copyright (c) Microsoft Corporation (see LICENSE.txt).
  • Famicom port, extended commands, characters, manual and samples:Copyright (c) 2026 @OKUNYON.
  • Programs you write with FC 6502 BASIC are yours to share or sell.
    This is an unofficial homebrew project. It is not affiliated with, licensed or endorsed by Microsoft or Nintendo. Microsoft is a trademark of Microsoft Corporation.

Family Computer, Famicom and Disk System are trademarks of Nintendo Co., Ltd.

Changelog

• 2026/11/11 ... V1.1
  • Ported and modified from Microsoft’s official 6502 BASIC source (MIT License)
  • PSET
  • BSAVE
  • BLOAD
  • MON
  • Minor bug fixes
• 2026/11/1 ... V1.0
  • COLOR
  • SCR$
  • SP16X
  • SP16Y
  • SP8X
  • SP8Y
  • BGDEF
  • SP8DEF
  • SP16DEF
  • PLAY
  • WAVE
  • SE
  • MUTE
  • TIME
  • CSAVE
  • CLOAD
  • Implement the Screen Editor
  • Minor bug fixes
  • Include a simple text manual
  • Load the program to play the test game
• 2026/10/18 ... V0.92
  • VSYNC
  • INKEY$
  • BEEP
  • SPR8
  • SPR16
  • SPROFF
  • PALETB
  • PALETS
  • Minor bug fixes
  • Sorry, I haven't put together a text file listing the commands yet.
    
    
• 2026/10/11 ... V0.91
  • CLS
  • LOCATE
  • PAD
  • Fixed STACK address
  • Revised keyboard input handling

• 2026/10/03...V0.90
  • Initial release