How it's done - Software Defined ROMs

The engineering deep-dive behind Software Defined Retro ROM: real-world MCU selection criteria, schematic design failures, PCB layout decisions, and embedded implementation choices that made nanosecond ROM emulation possible. This video breaks down the technical decisions behind SDRR - from why I didn't choose the Pico, ATMEGA or STM32F103, to PCB layout and routing in a two layer compact form factor, finishing off with scoping the working solution. Previous video (introduction): https://youtu.be/Jhe4LF5LrZ8 Github repo: https://piers.rocks/u/sdrr ⏰ **Timstamps** 00:00 🚀 Introduction 00:44 📄 Original ROM datasheet 05:13 📝 Requirements 06:55 ⚠️ Constraints 08:49 🎯 MCU Family Selection 13:19 ❌ STM32F1 (Failed) Schematic 17:40 ✅ STM32F4 Schematic 22:16 🔌 PCB Layout 25:00 💾 ROM Code 29:33 🔬 Scoping the Software ROM 31:15 🎬 Wrap up Video content copyright (c) 2025 piers.media Limited. All rights reserved.