FPS 0
Frame 0
Mapper —
PC $0000
Scan 0
Audio —
Drop a .nes file anywhere, or pick a built-in ROM ↗
Debugger
PPU Viewers
Memory
Trace
CRT / Video
Save / Rewind
Input
Self-Test
About
CPU Registers
0
0,0
Disassembly
Breakpoints
Pattern Tables palette:
Left: $0000 table · Right: $1000 table
Nametables
Sprites (OAM)
Palettes
Memory Viewer
Click a byte to edit.
Execution Trace
Logs each executed instruction (ring buffer 4096).
Event Log
CRT Shader
Performance
Green = frame time (ms). Line at 16.7ms.
Save States
Rewind
12s
Hold Backspace to rewind, Tab to fast-forward.
Settings
Keyboard Mapping (Player 1)
Click a button then press a key to rebind.
Turbo
15 Hz
Hold X = Turbo A, C = Turbo B.
Gamepad
No gamepad detected. Connect one and press a button.
CPU / System Self-Test
About
A self-contained, cycle-accurate NES emulator. Full 6502 core (official + illegal opcodes), loopy-scroll PPU with sprite-0 hit and overflow quirks, non-linearly mixed APU (2 pulse + triangle + noise + DMC), mappers 0/1/2/3/4/7/66 with MMC3 A12 IRQ, a real debugger, and a WebGL CRT shader.
All data stays in your browser (localStorage + IndexedDB for battery SRAM). Works offline. No ROMs are embedded — built-in content is generated at runtime.