https://howcpuworks.com/blogs/processsorbook/building-processors-from-the-ground-up

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  * Overview
  * Logic gates
  * Decoder
  * Register
  * CPU simulator
  * - ALU
  * - Adder
  * - Memory
  * - Clock
  * - Astable multivibrator
  * - Edge triggered bistables
  * - Micromemory
  * - Micromemory programming
  * - Signals
  * - Flags
  * - Implementing branching
  * - Connecting LCD
  * - Connecting the keyboard
  * - Heap, stack, static, instruction..
  * - Assembly
  * - Example programs
  * - Pipeling

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Building Processors from the Ground Up

August 30, 2023
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Overview

This is my processor that I built completely from transistors.
 [20230712_1]
In this interactive online book we will go in depth how I actually
built it, from implementing logic gates with transistors and building
registers to creating the instruction set and programming the hello
world and even dinosaur game. All of the material is free!

 

Why read this?

There are some projects on the internet that build small 8 bit
computers out of integrated circuits, like registers, bus selectors,
decoders, etc. this is not the focus of this book. We do not use any
integrated circuits, there is no hiding complexity.
There are also a lot of Youtube channels showcase their processors
built in the simulation. Don't get me wrong that is impressive, but
in the real world you cannot simulate, real world runs on atoms not
bits.
After you finish the book you will be able to say what every single
one of 2008 transistors do and why they do that. You will also
understand why some architecural choices were made,
be able to design your own processors and better understand what goes
on in modern ones.


Book elements

Every chapter explains one concept and they usually end by assembling
one part of the processor.
They also contain interactive simulations and questions.
This is an example of the logic gate simulator and a question:


An example of a circuit simulator and a question:

In general as we progress through the material, circuit questions
will be abstracted to logic gate questions and then component
questions.
We assemble small parts of it on a breadboard:
an image of a fritzing breadboard
And then show how concepts from chapters link to the processor.


 

 

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[Post comment]
Make lamp turn on each clock cycle if the button is pressed down.

Loading the circuit ....
Loading the circuit ....
Hint: You need to add one wire to the circuit. Find which component
does not have anything connecting to it.
Solution: We connected the output terminal of the button to one of
the input terminals of the AND gate. Press the "b" button to test.
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What will happen when you press on both of the inputs (L) and change
the inputs from L to H?

Hint: The gate of the output transistor will be at ground.
Solution: Output MOSFET will become unactive and the output will rise
to logic High.
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