Appendix K — Build your own AVR board

Purpose

Reduce a development board to the understandable minimum and then add infrastructure deliberately.

Stage 1 — Minimum system

Start from the ATmega1284P-PU datasheet and identify power pins, ground, AVCC/AREF requirements, RESET, clock choices and ISP.

Stage 2 — Breadboard

Build a conservative minimal system with decoupling, reset/programming access and a known clock strategy. Verify power before inserting/programming the MCU.

Stage 3 — Bring-up

1. inspect for shorts/polarity errors;
2. verify rails;
3. verify reset;
4. verify clock assumptions;
5. identify/program the MCU through ISP;
6. run a minimal GPIO test.

Stage 4 — Add peripherals

Add one function at a time: LED/button, UART, ADC source, buses and driver stages. Re-test after each addition.

Stage 5 — PCB

Translate the working architecture into schematic/PCB while preserving decoupling, return paths, programming access, test points and readable connectors.

EduBoard connection

EduBoard-AVR is the course reference implementation of these principles, but this appendix teaches how to reason about a minimal AVR board rather than merely copying its PCB.

Qualification

Keep breadboard/PCB observations distinct. Record schematic revision, board revision, programmer, supply and firmware used for bring-up.