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#beneatercpu#breadboardcpu#microcode

8-bit CPU control signal overview

Ben Eater

1.4M subscribers • 33 videos on Hallway

YouTube
  • Recommended by 1 person: 1 in engineering communities.
  • Presented by Ben Eater

Intermediate. Assumes working knowledge.

249K views9 years ago1 recommendation

HardwareSystems programmingCPUs and computer architectureElectronicsRetro computing

Ben Eater explains how control signals and microcode coordinate the components of an 8-bit breadboard computer.

This video goes over the control signals used in our 8-bit breadboard computer. Support me on Patreon: patreon.com/beneater See eater.net/bbcpu8-bus for more. Additional components used in this video: - 15x LEDs to indicate which control signals are active - 15x 470Ω resistors for the control signal LEDs - 15x 470Ω resistors for the bus LEDs - 2x 74LS04 Hex inverter (optional, but makes the control word simpler to interpret) - Red gel (e.g., amazon.com/dp/B004GE19E2) eater.net x.com/beneater patreon.com/beneater

Why it's here

1 person recommends this

What people say. Recommended as a clear, hands-on demonstration of how CPU microcode and control logic function.

u/OutOfBandDevin r/programming • Recommends

On “Two undocumented Intel x86 instructions discovered that can be used to modify microcode”

The microcode is really pretty much just a mapping table... when you say instruction 123 use this register, that ALU and count three clocks. it's not an application it a very simple state machine. For a simplified example of microcode check out the 8bit TTL CPU series by Ben Eater on Youtube. (24) 8-bit CPU control signal overview - YouTube x86 is much more complex than his design but at a high level they work the same.
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