Adafruit
Adafruit WCH CH9102F Friend - USB to Serial Converter
The Adafruit CH9102F Friend is a USB-to-Serial converter breakout featuring the affordable WCH CH9102F chip and a modern USB Type-C connector. It uploads cod...
The Adafruit CH9102F Friend is a USB-to-Serial converter breakout featuring the affordable WCH CH9102F chip and a modern USB Type-C connector. It uploads code at up to 3 Mbit/s and includes auto-reset for Arduino/ATmega328 boards — no manual pin manipulation needed.
The pinout matches standard FTDI cables by default: RTS on pin 6, +5V power, and 3.3V signal levels (5V compliant). It works with any Arduino, ESP8266, ESP32, or other microcontroller that uses an FTDI-style serial port for communication and code upload. All modem control pins (DTR, RI, DSR, etc.) are broken out on the side for advanced use.
Key Features
- CH9102F USB-Serial Chip – Affordable, widely available, with good driver support
- USB Type-C Connector – Works with any modern computer
- Up to 3 Mbit/s – Fast upload speeds for quick development
- Auto-Reset – Automatic reset for Arduino/ATmega328 boards via RTS/DTR
- FTDI-Compatible Pinout – Drop-in replacement for FTDI cables
- 3.3V Signal Levels – 5V compliant for compatibility with most 3.3V and 5V systems
- Full Modem Control Pins – DTR, RTS, RI, DSR, DCD, and CTS broken out
- RX/TX LEDs – Visual indication of data activity
Ideal For
- Programming Arduino, ESP8266, ESP32, and other FTDI-port microcontrollers
- USB-to-serial debugging and communication
- Replacing FTDI, FT231x, or CP210x adapters
- Serial console access to embedded systems
Package Contents
- 1× Adafruit CH9102F Friend (fully assembled and tested)
- 1× Right-angle socket header (for FTDI-style edge connection)
- 1× Male header strip (for breadboard use)
Resources
- WCH USB-Serial Driver Installation Guide – Windows and macOS driver setup
Jargon buster
Plain-language definitions for the technical terms used above.
- breakout
- A breakout is a small circuit board that makes a tiny or hard-to-solder component easier to connect to with standard pins. It matters because this OLED module can be wired into a microcontroller project without needing to solder directly to the display’s fine contacts.
- CTS
- CTS stands for Clear To Send, a serial flow-control signal that tells the other device it may transmit. It matters for reliable high-speed serial communication where buffers could otherwise overflow.
- ESP32
- ESP32 is a family of microcontroller modules with built-in wireless features such as Bluetooth and WiFi. Knowing this product uses an ESP32-based module helps explain how it provides wireless serial communication and firmware update features.
- microcontroller
- A microcontroller is a small computer on a chip that runs your program and controls connected inputs and outputs. For this product, it is the part that reads buttons and sensors, drives the display and speaker, and communicates over Bluetooth.
- RTS
- RTS stands for Request To Send, a serial flow-control signal used to manage when a device is ready to receive data. It matters when moving fast serial streams because flow control can help prevent lost data.
- USB Type-C
- A reversible USB connector used for power and data on many modern devices. On this kit it indicates an alternate 5V power input, which may be useful for setup or charging without the solar panel.
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Prototyping & Wiring
Related Tutorials
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