🌉 ESP32 UART Bridge

A lightning-fast, transparent serial bridge for the ESP32. This project turns your ESP32 into a full-duplex USB-to-Serial adapter, using FreeRTOS to pin separate transmit and receive tasks to different CPU cores for maximum, non-blocking throughput.

🔌 Wiring

ESP32 Pin	Connection
GPIO 16 (RX)	Target Device TX
GPIO 17 (TX)	Target Device RX
GND	Target Device GND

⚠️ 3.3V Logic Warning: The ESP32 is strictly 3.3V. If your target device operates at 5V, use a logic level shifter or a voltage divider on the ESP32's RX pin to prevent permanent chip damage.

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🚀 Installation

Simply download and upload v1 of the source code to your ESP32 using the Arduino IDE (Core 2.x / 3.x).

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💡 Tips & Variations

• Bridge two external devices (No USB): Swap Serial for a second HardwareSerial instance on different pins.
• Asymmetrical Speeds: The bridge is just relaying bytes. You can pass completely different baud rates to the UART initializations if your devices run at different speeds.
• Hardware Flow Control: Need RTS/CTS? Pass the extra parameters natively directly into UartB.begin().
• Need more speed? At 115200 baud, this uses ~2% CPU. For >1 Mbaud, increase the buffer sizes and bump the baud rates on both sides.

🛑 Common Gotchas

• Forbidden Pins: Never use UART1's default pins (GPIO 9 & 10) on a classic ESP32. These are tied to the internal SPI flash.
• Shhh! No Debugging: Do not use Serial.print("Hello") in this sketch. It will inject your text directly into the target device's data stream.
• Baud Matching: On standard boards (CP2102/CH340), your PC terminal must match the bridge's baud rate. (On ESP32-S2/S3 with native USB, the PC baud rate is ignored).