Complete XIAO ESP32S3 Carrier Board - Final Wiring Diagram With LED Test Circuit + E-Ink Connections (D10=MOSI, D8=SCK) XIAO ESP32S3 Seeed 113991114 USB-C 5V 1 GND 2 3V3 3 D0 4 D1 5 D2 6 D3 7 D4 (SDA) 8 D5 (SCL) 9 D6 10 D7 (TX) 11 D8 (SCK) 12 D9 (MISO) 13 D10 (MOSI) 14 D10=GPIO9 (MOSI), D9=GPIO8 (MISO), D8=GPIO7 (SCK) LED Test Circuit D0 D1 LED (Red) 0805 or 1206 R1 1kΩ 0805 or 1206 GND J2: I2C Connector 4-pin Male Header 1: SDA (D4) 2: SCL (D5) 3: 3V3 4: GND J3: SPI Connector 8-pin Male Header (E-Ink) 1: MOSI (D10) 2: SCK (D8) 3: CS (D3) 4: DC (D2) 5: RST (D1) 6: BUSY (D6) 7: 3V3 8: GND 3V3 GND ✅ Week 1 Testing Plan Step 1: Upload blink code to test LED on D0 → Proves power & basic circuit works Step 2: Plug I2C sensor into J2, run I2C scanner → Proves I2C pins work Step 3: When you get e-ink display, plug into J3 → Proves SPI pins work