# Pinout notes (ESP32-S3-DevKitC-1)

Strapping and USB pins differ by revision — **avoid** GPIO `19–20` for PN532 when using USB-Serial/JTAG on many boards. Prefer **SPI2** on free GPIOs from the [DevKitC-1 user guide](https://docs.espressif.com/projects/esp-dev-kits/en/latest/esp32s3/esp32-s3-devkitc-1/user_guide_v1.1.html).

## Kconfig defaults (examples only)

The firmware Kconfig ships **example** GPIOs:

- **SPI**: MOSI `11`, MISO `13`, SCLK `12`, CS `10`
- **I2C**: SDA `8`, SCL `9`

**You must verify** these against your PCB/breadboard and PN532 breakout (Adafruit / Elechouse / clones often label SPI and I2C jumpers).

## PN532 wiring checklist

- **SPI**: connect `RSTO`/`RST` to MCU if exposed; some breakouts auto-reset via I2C/SPI activity.
- **I2C**: set address pins per module (usually **0x24** 7‑bit).
- **Power**: **3.3V** logic on ESP32; ensure PN532 module is 3.3V compliant (level-shift if using a 5V Arduino-style shield).

## Transport selection

Start with the bus your breakout is jumpered for — **I2C is often simplest** on ESP32 for bring-up; SPI may require **lower clock** initially (e.g. **100 kHz**).