Electronics Design

For this week’s assignment, I designed a custom breakout board for the Seeed XIAO RP2040 using EasyEDA – a powerful online tool for schematic capture, PCB layout, and even simulation. The idea behind this project was to make prototyping and debugging with the XIAO RP2040 much easier by breaking out all essential pins into a clean and accessible layout.

Why a Breakout Board?

The XIAO RP2040 is a super-compact development board based on the Raspberry Pi RP2040 chip. It’s packed with features but due to its small size, connecting modules or sensors directly becomes inconvenient, especially on a breadboard. So I decided to create a breakout board that:

Exposes power lines (5V, 3.3V, GND)
Breaks out all GPIOs
Separates UART, I2C, SPI interfaces
Includes a power indicator LED

This board will act like a personal development platform for rapid prototyping.

Exploring EasyEDA

This week, I stepped into EasyEDA for the first time, and let me tell you—it’s a pretty solid tool for designing circuits. It’s got everything: a schematic editor, PCB layout tool, and even a simulation feature to check if your circuit will work before you physically build it.

Key Features of EasyEDA:

Schematic Editor – Draw circuit diagrams with prebuilt components.
PCB Layout Editor – Convert schematics into a printable PCB layout.
Simulation – Test how your circuit will function before making it.
Component Library – Access thousands of electronic parts.
Auto Router – Automatically routes PCB traces to avoid errors.

Schematic Editor

The schematic editor in EasyEDA is where I began. I added the XIAO RP2040 footprint from the LCSC parts library. The symbol was already pre-defined with all pin names, which made things easier.

I then started placing other components like:

Headers (Pin Connectors) – to break out GPIO, power, and communication lines.
LED + Resistor – for power indication.
Net Labels – These help identify and organize connections instead of drawing long wires everywhere.
GND and Power Ports – These global symbols automatically connect all related pins without visible wires.

HEADER PINS I used:

LED & Resistor I used:

The hotkeys in EasyEDA were also useful. For example:

W to quickly draw wires
Shift+R to rotate components
Spacebar for switching between tools

Component Libraries

I explored both EasyEDA standard libraries and LCSC libraries. The LCSC ones are useful especially if you’re planning to manufacture the board via JLCPCB, as they show availability and part numbers directly.

Designing the Schematic

Power Section:

Used a 330Ω resistor and SMD LED for 5V power indication.
Connected 3.3V, 5V, and GND to headers H2 and H3.

Communication Interfaces:

UART (TX, RX): Routed to headers CN2 and U6
I2C (SDA, SCL): Routed to CN1 and U6 for flexibility
SPI (MISO, MOSI, SCK): Brought out to U5 for modules like OLEDs or SD cards

GPIO Pins:

Connected all digital pins (D0–D10, etc.) to headers H3–H6 for general use.

Each header was logically grouped and labeled. I also added net labels to keep the schematic clean and reduce wire clutter.

this was my schematic at the first try , but it was looking a bit unorganised so i tried making it better at connections and understanding.

Refining the Schematic

After completing the first draft, I took some time to refine and clean up the schematic. Here's what I changed in version 2:

I properly labeled all connections, such as 5V, 3V3, GND, SDA, SCL, TX, RX, etc.
I aligned all the headers and connectors for better readability
Used standardized naming conventions and grid alignment
Made sure to clearly mark power rails and communication lines
This improved version not only looked more professional but also made the PCB layout easier to follow later on.

Final Header Pin Mapping

Header	Pins	Function
H2	5V, 3V3, GND	Power
H3–H6	GPIO Pins	General Purpose I/O
U5	MISO, MOSI, SCK, TX, RX	SPI + UART
U6	SDA, SCL, TX	I2C + UART
CN1	SDA, SCL	I2C
CN2	TX, RX	UART

Here's my next process of making the actual pcb and milling it

Electronic Production