A CPU built from discrete transistors is a computer processor that is constructed using individual transistors, rather than integrated circuits (ICs). This is a very challenging task, as it requires many transistors to be interconnected in a precise and complex manner. However, there have been a number of successful projects to build CPUs from discrete transistors in recent years.
One of the most notable examples is the TraNOR computer, which was built by Dennis Kuschel. The TraNOR CPU contains 2,495 discrete MOSFETs and can run at up to 7MHz. It is software-compatible with the popular 8-bit 6502 microprocessor, and can even support modern interfaces like I2C and SPI.
Another example is the transistor computer built by Reddit user Weekly_Salamander_78. This computer uses over 2,000 individual transistors to implement a complete 11-bit CPU. The creator has also published an online interactive book that walks through the process of building the computer.
CPUs built from discrete transistors are not practical for everyday use, as they are much larger, slower, and more power-hungry than modern IC-based CPUs. However, they are interesting as a technical challenge and can be used to learn more about how CPUs work.
Here are some of the benefits and drawbacks of CPUs built from discrete transistors:
Benefits:
More educational and informative: Building a CPU from discrete transistors can be a great way to learn more about how CPUs work and how they are designed.
More modular: CPUs built from discrete transistors can be easily modified or upgraded.
More customizable: CPUs built from discrete transistors can be tailored to specific needs.
Drawbacks:
Larger: CPUs built from discrete transistors are much larger than modern IC-based CPUs.
Slower: CPUs built from discrete transistors are much slower than modern IC-based CPUs.
More power-hungry: CPUs built from discrete transistors are much more power-hungry than modern IC-based CPUs.
Overall, CPUs built from discrete transistors are a niche technology with limited practical applications. However, they can be a fun and rewarding project for hobbyists and enthusiasts.
