7Semi CH343 Pico USB to TTL Serial Converter Board – (3.3V / 5V Selectable)

The 7Semi CH343 Pico USB to TTL Converter is a super-compact USB-to-serial adapter based on the WCH CH343 chipset. Designed for embedded systems and minimal PCB real estate, it supports both 3.3V and 5V logic levels, making it compatible with a wide range of microcontrollers including ESP32, STM32, Raspberry Pi, and Arduino.

This board is ideal for firmware flashing, serial debugging, UART communication, and USB interfacing in compact or mobile electronics projects.

Features

• CH343 USB to UART Bridge IC
• Bi-directional Serial Communication (RX/TX)
• Selectable Voltage Logic – 3.3V or 5V via onboard jumper/solder bridge
• Ultra-Compact Pico Form Factor – easy to embed in tiny enclosures
• USB D+ / D- Breakout Available – for advanced interfacing
• Native Windows/Linux/Mac Driver Support

Applications

•  Firmware flashing for ESP8266 / ESP32 / STM32 / Arduino

•  Serial debugging and monitoring

•  USB-to-TTL communication bridge in test jigs

•  Battery-powered microcontroller programming

•  Serial communication with GPS, GSM, modems, sensors

What is Included?

• 1 × 7Semi CH343 USB to TTL Pico Serial Converter Board

Frequently Asked Questions (FAQ)

Q1: How do I switch between 3.3V and 5V logic levels?
A: Use the onboard jumper or solder bridge between the "3.3V" or "5V" pads to configure the output logic level.

Q2: Does this board work with Arduino IDE or ESPHome?
A: Yes, it's fully compatible with Arduino IDE, PlatformIO, and ESPHome for serial communication or firmware flashing.

Q3: Is a USB cable included?
A: No. A micro-USB or USB-C to pin header adapter (depending on your setup) needs to be connected externally.

Q4: Can I connect this directly to Raspberry Pi GPIO?
A: Yes, but make sure to match the logic level (3.3V) to avoid damaging the Pi.

Q5: Is the D+ and D- breakout required?
A: Not for most applications. It's only for low-level USB interfacing or signal capture/debugging.

Resources

• CH343 Datasheet