Shard - Custom ESP32 S3 Board

Shard is an open source ESP32 S3 board that I designed as a summer project to learn more about electronics and PCB design.

Core features:

• 16 MB Flash storage
• 8 MB RAM
• WiFi and Bluethoot capabilities
• Built-in Neopixel RGB LED
• 21 configurable GPIO pins
• Up to 16V for external Power supply
• UART & Configurable SPI and I2C pins

The board itself is pretty small, 4.6x4.8cm and doesn't have mounting holes unfortunately. It is designed to be an all-feature development board for prototyping.

Programming

Uploading

The board doesn't come with a USB-UART bridge, so the firmware uploading requires user input:

• When the uploading process starts, hold the RESET button
• Immediately after you pressed it, press the BOOT button and then release the RESET button
• After the code is uploaded, press the RESET button again to exit Download Mode, so that the board can execute the code.

Aruino IDE 2 programming

To program this board with the Arduino IDE, you have to:

• Install the "esp32" board manager.
• then select the UM-PROS3 board
• when uploading, follow the steps listed in the Uploading section.

PlatformIO programming

I first programmed this board using PlatformIO and I used this platformio.ini file:

[env:esp32-s3-devkitc-1]
platform = espressif32
board = um_pros3
framework = arduino

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

build_flags = 
    -DCORE_DEBUG_LEVEL=5

I specified the flash size and the flash partition just to make sure everything worked as expected, but the UM-PROS3 board should be configuring these by default.

Also, this is the partition I used:

# 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,

PlatformIO should find the board automatically. When uploading, still follow the steps in the Uploading section.

Reference

To design this board, I mainly referred to the Espressif's ESP32-S3 Hardware Design Guidelines.