NES© Visual Debugger

Select cartridge:

About

This is a NES© emulator that visually exposes the internals of the system, to aid in understanding. Learn more about the NES in our series on NES internals.

Note: The Debugger doesn’t yet run at full speed in the browser. If you just want to play, check out our full speed emulator instead.

If you would like to use screenshots from this system, please include a link and attribution:

NES Visual Debugger by EmulationOnline
https://www.emulationonline.com/systems/nes/debugger

Controls

D-Pad: Arrow Keys
B: Z
A: X
Start: Enter
Select: Quote('), often left of Enter

Debug controls:
T: Toggle run/pause
S: Single step cpu.
F: Run for one frame

Known limitations

The browser version is currently very slow.
It only supports basic cartridge hardware, aka NROM.
Rendering is not cycle accurate. Instead, it simply combines the current state of the nametables and overlays sprites.
Window scrolling is not implemented.

NES© Visual Debugger

About

Controls

Known limitations

Disclaimer