Schematics | TTL CPU Schematics Submitted by Andrew Wasson on Sat, - 1:24am I'm starting to make some progress with Eagle (light) and I'll be adding schematic diagrams of all of the circuits that make up my CPU. CPU (Central Processing Unit) Block Diagram CPU performance also depends upon the RAM, bus speed and cache size as well. Called as heart of the computer. Block diagram Working: CPU consists of three basic units: control unit, Arithmetic Logical Unit (ALU) and memory unit. Input is given through the input devices to CPU. Control unit controls communication within ALU and memory unit.