Shard - ESP32-S3 Development Board

Shard is a simple and open-source ESP32-S3 development board designed for prototyping and embedded development. Featuring a compact form factor with comprehensive GPIO access and high-performance specifications.

Table of Contents

• Features
• Specifications
• Getting Started
• Programming
• Pinout
• Hardware Design
• Contributing

Features

• High Performance: ESP32-S3 dual-core processor with WiFi and Bluetooth capabilities
• Generous Memory: 16 MB Flash storage
• Rich I/O: 21 configurable GPIO pins with UART, SPI, and I2C support
• Visual Feedback: Built-in addressable RGB LED (Neopixel)
• Flexible Power: Supports external power supply up to 16V
• Compact Design: Small form factor (4.6 × 4.8 cm) ideal for prototyping

Specifications

Feature	Specification
MCU	ESP32-S3 dual-core Xtensa LX7
Flash Memory	16 MB
GPIO Pins	21
Connectivity	WiFi 802.11 b/g/n, Bluetooth 5.0 LE
Power Input	3.3V - 16V (external), 5V (USB)
Dimensions	46 × 48 mm
LED Indicator	Addressable RGB (Neopixel)
Buttons	Reset, Boot

Getting Started

Power Supply

• USB Power: 5V via USB-C
• External Power: 3.3V - 16V via power pins

Programming

Upload Process

Since the board lacks a built-in USB-UART bridge, firmware uploads require manual boot sequence:

1. Initiate Upload: Start the upload process in your IDE
2. Enter Download Mode:
   • Press and hold the RESET button
   • Press and release the BOOT button
   • Release the RESET button
3. Complete Upload: Wait for upload to finish
4. Exit Download Mode: Press RESET button to start execution

Arduino IDE Setup

Installation

1. Install the ESP32 board package:

   • Open Arduino IDE 2.x

   • Go to File → Preferences

   • Add to Additional Board Manager URLs:

     https://raw.githubusercontent.com/espressif/arduino-esp32/gh-pages/package_esp32_index.json
     

   • Go to Tools → Board → Boards Manager

   • Search for "esp32" and install

2. Board Configuration:

   • Select Tools → Board → ESP32 Arduino → UM-PROS3
   • Set Upload Speed: 921600
   • Set Flash Size: 16MB
   • Set Partition Scheme: Default 16MB with spiffs

PlatformIO Setup

Create a platformio.ini file in your project root:

[env:env:esp32-s3-shard]
platform = espressif32
board = shard ; or `um-pros3`
framework = arduino

board_build.flash_mode = dio
board_build.flash_size = 16MB
board_build.partitions = default_16MB.csv

To use my custom board config file shard.json, download it and place it under the boards folder inside your project.

Optional Custom Partition Table

This is the default partition table (partitions.csv):

# Name , Type, SubType, Offset  , Size    , Flags
nvs    , data, nvs    , 0x9000  , 0x5000  , 
otadata, data, ota    , 0xe000  , 0x2000  , 
app0   , app , ota_0  , 0x10000 , 0x700000, 
app1   , app , ota_1  , 0x710000, 0x700000, 
spiffs , data, spiffs , 0xe10000, 0x1F0000, 

To specify a different partition table, modify the partitions entry inside shard.json

Follow the upload process when programming with PlatformIO.

Pinout

Pin Mapping Summary

Function	GPIO Pins	Notes
Digital I/O	GPIO1-21	3.3V logic level
ADC	GPIO1-14	12-bit resolution
Touch	GPIO1-14	Capacitive touch sensing
SPI	Configurable
I2C	Configurable
UART	Configurable	TX, RX
PWM	All GPIO
RGB LED	GPIO21	Built-in addressable LED

Hardware Design

All design files are open-source and available in this repository:

• Schematic: Shard.kicad_sch or Shard.pdf
• PCB Layout: Shard.kicad_pcb
• Gerber Files: shard-gerbers/
• Bill of Materials: Shard_BOM.xlsx
• Part Placement: Shard_CPL.xlsx

Contributing

Feel free to open a pull request or an issue

References

• ESP32-S3 Hardware Design Guidelines
• ESP32-S3 Datasheet
• Arduino ESP32 Documentation

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This project is licensed under the MIT License - see the LICENSE file for details.