18 May 2023
Building a retro gaming computer using logic gates
This week I had the pleasure of welcoming Richard Pawson to Fulford School in York and we had a really exciting conversation about helping GCSE and A Level Computer Science students build links between topics. It can be really hard to promote deep understanding when subject knowledge is separated into discrete sections of an exam board syllabus but the "how" and "why" questions of motivated students really make the job worthwhile and enjoyable.
We talked about light bulb moments of connecting the dots all the way between logic gates and the structure and function of a processor: how hard it can be for students to grasp how each part of a CPU is made up of NAND / AND / OR / NOT / XOR gates.
Richard very kindly donated a Gigatron to my students which is a kit to solder together a working microcontroller capable of playing retro games but made entirely of TTL ICs (no Raspberry Pi, arduino or other microcontroller in sight). I promised to try to document the process of soldering it together and exploring how all the parts work.
Gigatron kits were developed by Marcel van Kervinck and Walter Belgers as a simple(ish) 8 bit retro microcomputer made entirely out of 1970s era TTL integrated circuits. The finished version connects to a VGA display (no graphics card - the signals are all generated by software) and uses a game pad or keyboard to control some retro games. You can try out an simulated version here: https://gigatron.io/emu/
I run a Game Development Club on a Thursday after school with many students who create and play their own games. Today, I showed them the gigatron and asked for volunteers to help solder all the parts together.
I promised Richard that I'd attempt to write up the learning process of finding out how all the different parts of the computer worked in case any student or teacher would benefit from an introduction to the exciting crossover between electronics and computer science.
If you're interested in following that journey, I'll share it here: https://blog.withcode.uk/2023/05/how-do-computers-work-part-1-introduction/
If you have any questions, suggestions or comments - my students and I would love to hear your thoughts via the CAS discussion forum below.