Build an 8-bit computer from scratch - Ben Eater
I built a programmable 8-bit computer from scratch on breadboards using only simple logic gates. I documented the whole project in a series of YouTube videos and on this web site. Watch this video for an introduction:
Build an 8-bit computer from scratch - Ben Eater
CPU control logic. The control logic is the heart of the CPU. It’s what defines the opcodes the processor recognizes and what happens when it executes each instruction. Videos
Ben Eater
The arithmetic logic unit (ALU) part of a CPU is usually capable of performing various arithmetic, bitwise, and comparison operations on binary numbers. In our simple breadboard CPU, the ALU is just able to add and subtract.
Build an 8-bit computer from scratch - Ben Eater
8-bit CPU control signal overview Notes Rather than soldering the LEDs for the bus together as shown in the videos, you can put them in an open space on the breadboard.
Build an 8-bit computer from scratch - Ben Eater
In our simple breadboard CPU, we’ll build three 8-bit registers: A, B, and IR. The A and B registers are general-purpose registers. IR (the instruction register) works similarly, but we’ll only use it for storing the current instruction that’s being executed.
Ben Eater
Build an 8-bit CPU from scratch. This tutorial walks through building a fully programmable 8-bit computer from simple logic gates on breadboards. Included are parts lists, sources, and schematics to make it easier to follow along or even build your own! Check it out
Build an 8-bit computer from scratch - Ben Eater
I create tutorial-style videos about electronics, computer architecture, networking, and various other technical subjects.
Ben Eater
Below are schematics for the entire computer. You can also download this Kicad project , which includes all of the schematics and a PCB layout. High level overview
Build an 8-bit computer from scratch - Ben Eater
If you’re interested in following along with my 8-bit breadboard computer videos and building your own, I’ve assembled kits that include all of the components I used in the videos, including the Arduino nano (used to program the LED and control EEPROMs) and a 5 volt power supply.
Ben Eater
The computer’s clock is used to synchronize all operations. The clock we’re building is based on the popular 555 timer IC. The videos go into some detail on the operation of the 555 and use it in three different ways. Our clock is adjustable-speed (from less than 1Hz to a few hundred Hz).