SAP I: Minimal Computer from basic Logic ICs

Posted on August 28, 2018 · 3 mins read · English · Nuwan Jaliyagoda

Final View

Does anyone have an idea about early computers? The age before Micro controllers/ Microprocessors? I have just now completed a project that takes me into that time.

This is an 8-bit Minimum Computer (Computation Machine) [1] that made from simple logic ICs, flip-flops and a few memory modules. It has a memory of 16 bytes and its maximum clock speed is not more than 5 Hz.

The whole design is based on SAP-I Architecture and design was obtained from Ben Eater’s Youtube Channel [2]. Currently, it has 9 instructions (based on Intel 8080 instructions) and can be programmed it using machine language (That means programming from 1s and 0s)

The project was started as a project for CO221: Digital Design Course, Department of Computer Engineering, University of Peradeniya.

All the Printed Circuit boards were designed from the basics by us using Fritzing, fabricated by using the CNC, Builder_V3 and soldered and assembled by us. It took 2 months to complete the fabrications and another month for build motherboard (30x40cm) and debugging.

After the evolution of the project, we hope to make it free and open source under Apache License 2.0 Special thanks to

  • Dr. Kamalanath Samarakoon for giving the idea & source materials about SAP-I
  • Dr. S.D. Dewasurendra
  • Miss. Narmada Balasooriya, Miss. Thilini Dahanayaka and all the instructors on the Department of Computer Engineering
  • My team members; Suneth Samarasinghe, Pubudu Premathilake, Dilshani Karunarathne, Wishma Herath, Pasan Thennakoon & Irfan Mohommad


Design Stage

While prototyping

While testing

At a end of PCB fabrication

Final assembly