Like Visual 6502, but you build the transistors yourself
Visual 6502 (visual6502.org) is a transistor-level simulation of the classic MOS 6502 processor. Its team exposed and photographed a real 6502 die in 2009, traced about 20,000 physical components into polygons, and turned them into a simulation that runs in the browser, colouring every part by its high or low state as the chip steps through a program. It debuted at SIGGRAPH 2010, and the site also offers visual simulations of the ARM1 and the Motorola 6800. If that is what brought you here, digiwleea is a free, in-browser alternative with a different angle: you build a computer from the transistor up.
What Visual 6502 is good at
It is a remarkable piece of computer archaeology: the simulation is accurate enough to run classic 6502 programs, including Atari games, and you can watch a real historic chip read memory, move data on its buses and step through instructions, transistor by transistor. Nothing else shows a production CPU so directly. (digiwleea is an independent project, not affiliated with Visual6502.org.)
How digiwleea is different
Visual 6502 lets you watch a finished chip with thousands of parts; digiwleea has you build one yourself, small enough to understand. You start with single NMOS and PMOS transistors, wire them into NOT and NAND gates, and compose those into adders, latches, registers, RAM and control logic up to a working 8-bit CPU that you program in assembly, following a guided 40+ level course with theory lessons and an AI tutor (Wleea). Visual 6502 is the better pick for studying a real historic processor; digiwleea is the better pick for building and understanding one from scratch.
| Visual 6502 | digiwleea | |
|---|---|---|
| What it is | A simulation of the real MOS 6502 chip | A lab where you build the circuits |
| Scale | A real chip: about 20,000 traced components | Small circuits you build yourself |
| You | Watch and step a finished chip | Build gates, then a CPU, then program it |
| Runs in | The browser | The browser |
| Guided course | No (a research and reference project) | Yes, 40+ levels and theory lessons |
No sign-up is needed to start: open the lab and place your first transistor, or read the free theory course. The account (and the AI tutor) are optional.
See for yourself: build a logic gate from transistors in the simulator, then follow the path from sand to an 8-bit CPU.
Open the digiwleea lab →Frequently asked
Is digiwleea a good Visual 6502 alternative?
Yes, if you want to understand digital logic from the ground up. digiwleea is a free, in-browser simulator with a guided 40+ level course where you build every gate from CMOS transistors and work up to a real 8-bit CPU, with an AI tutor to help.
Is digiwleea free?
The sandbox lab and the first act of the course are free and need no sign-up. An optional account adds the AI tutor and cross-device sync; the full course and expanded AI tutoring are included in the monthly or annual Premium subscription.
Do I need to install anything?
No. digiwleea runs entirely in your browser, on desktop or mobile, and works offline once loaded.