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The ESP32-S3 Schematic is Fully Wired

Today the Dilder schematic got its biggest overhaul yet. The RP2040 is officially gone, replaced by the ESP32-S3-WROOM-1-N16R8 module with every net wired and validated.

What Changed

The old schematic had 33 components with a bare RP2040 chip that needed external flash, a crystal, crystal load caps, USB series resistors, and QSPI wiring. The ESP32-S3 module integrates all of that — flash, PSRAM, crystal, and RF frontend are all inside the metal can.

Removed: RP2040, W25Q16JV flash, 12MHz crystal, 2x 15pF caps, 2x 27R USB resistors, ATGM336H GPS module

Added: ESP32-S3-WROOM-1-N16R8 (one module replaces six components)

Component count dropped from 33 to 20. Simpler BOM, easier assembly, fewer things to go wrong.

The Wiring

Every net is connected via labeled wire stubs in the KiCad schematic:

  • Power: USB-C VBUS through SS34 Schottky to TP4056 charger, battery protection (DW01A + FS8205A), through AMS1117-3.3 LDO to the 3.3V rail that feeds everything
  • E-Paper SPI: GPIO9 (CLK), GPIO10 (MOSI), GPIO3 (DC), GPIO11 (RST), GPIO46 (CS), GPIO12 (BUSY) to the 8-pin JST-SH connector
  • Accelerometer I2C: GPIO16 (SDA), GPIO17 (SCL) to LIS2DH12TR with 10k pull-ups
  • Joystick: GPIO4-8 for UP/DOWN/LEFT/RIGHT/CENTER, active LOW with internal pull-ups
  • USB: GPIO19 (D-) and GPIO20 (D+) wired directly to USB-C — no series resistors needed thanks to native USB-OTG
  • EN: 10k pull-up to keep the module running

The BOM

A full bill of materials is now tracked in hardware-design/BOM.md with LCSC part numbers for every component. Total cost per board: ~$4.18. The most expensive part is the ESP32-S3 module ($2.80) — the LIS2DH12TR accelerometer is just $0.46, and everything else is pennies.

11 Reference Designs

To sanity-check the design, I also collected 11 open-source ESP32 KiCad projects that share features with the Dilder. The most useful are:

  • PocketMage PDA — an ESP32-S3 e-ink handheld with 1800 GitHub stars
  • Lilka — a Ukrainian ESP32-S3 gaming console with D-pad buttons
  • Ducky Board — the simplest possible ESP32-S3 + e-paper + battery board
  • BitwiseAjeet — uses the exact same TP4056 charger IC

All 11 are in hardware-design/examples/ with detailed ABOUT.md files describing their origin, what's relevant to Dilder, and which KiCad files to look at.

Next Steps

The schematic is done. The PCB placement script (build_esp32s3.py) already has the ESP32-S3 components positioned on a 45x80mm 4-layer board. Next up: routing the traces, running DRC, and generating Gerber files for JLCPCB.