CP2102 Micro USB to TTL UART Serial Converter Module – 3.3V/5V

The CP2102 Micro USB to TTL UART Converter Module provides a simple interface between a computer's USB port and TTL-level serial devices.

Based on the Silicon Labs CP2102 USB-to-UART bridge, the module creates a virtual COM port on your computer, allowing serial communication, debugging and programming of microcontrollers and embedded electronics.

Its compact design, Micro USB connector and accessible TXD, RXD and DTR signals make it useful for Arduino, ESP8266, ESP32, STM32 and many other UART-based projects.

Technical Specifications

• USB-UART IC: Silicon Labs CP2102
• Interface: USB to TTL UART
• USB Connector: Micro USB
• USB Standard: USB 2.0 Full Speed
• USB Speed: Up to 12Mbps
• UART Baud Rate: 300bps to 1Mbps
• UART Data Bits: 5, 6, 7 or 8
• Stop Bits: 1, 1.5 or 2
• Parity: None, Odd, Even, Mark or Space
• UART Logic: TTL-Level Serial
• 3.3V Output: Available
• 5V Output: Available from USB on common module versions
• DTR Output: Available
• Virtual COM Port: Yes
• Operating Systems: Windows, macOS & Linux with compatible CP210x drivers
• Typical Module Size: Approx. 16 × 20mm

Pin Configuration

Typical 6-pin versions provide:

+5V – 5V supply from USB

GND – Ground

TXD – UART transmit output

RXD – UART receive input

DTR – Data Terminal Ready / reset control signal

3V3 – Regulated 3.3V output

Pin order should always be checked against the markings printed on the actual module before connection.

Basic UART Connection

For standard serial communication:

CP2102 TXD → Target RX

CP2102 RXD → Target TX

CP2102 GND → Target GND

TX and RX must be cross-connected.

A common ground connection between the converter and the target device is required for reliable UART communication.

Virtual COM Port

When connected to a computer, the CP2102 appears as a standard serial COM port after the appropriate CP210x driver is installed.

It can then be used with applications such as:

• Arduino IDE
• PlatformIO
• Serial Monitor
• PuTTY
• Tera Term
• Programming Utilities
• Terminal Software
• Custom Serial Applications

Microcontroller Programming & Debugging

The module is useful for communicating with or programming UART-enabled devices such as:

• Arduino Pro Mini
• ATmega Microcontrollers
• ESP8266
• ESP32
• STM32
• PIC
• AVR
• GPS Modules
• GSM Modules
• Bluetooth Modules
• Serial Sensors
• Embedded Development Boards

Availability of automatic programming/reset depends on the target board's reset and boot circuitry.

DTR Output

The DTR (Data Terminal Ready) signal can be used by compatible development boards for automatic reset or programming control.

For example, DTR is commonly useful when programming boards such as the Arduino Pro Mini through a USB-to-UART adapter.

3.3V & 5V Power Outputs

Common CP2102 Micro USB modules provide access to both:

5V from the USB connection

and

3.3V from the CP2102's onboard regulator

These outputs are intended for small, low-current circuits.

Do not use the module's power pins to supply motors, servos, relays or other high-current loads.

USB 2.0 Interface

The CP2102 includes an integrated USB transceiver and clock circuitry and supports USB 2.0 Full Speed at 12Mbps.

The actual UART communication speed is separate from the USB bus speed, with the classic CP2102 supporting UART baud rates from 300bps to 1Mbps.

Applications

Ideal for:

• Microcontroller Programming
• Arduino Programming
• ESP8266 / ESP32 Development
• UART Communication
• Serial Debugging
• Embedded System Development
• GPS Module Communication
• GSM / GPRS Modules
• Bluetooth Serial Modules
• Serial Sensor Testing
• Electronics Repair
• Firmware Development
• Breadboard Prototyping
• Educational Electronics

Important Note

This module provides TTL-level UART, not traditional ±RS-232 voltage levels.

Do not connect the TXD or RXD pins directly to an RS-232 port such as a DB9 serial interface. An RS-232 level converter such as a MAX232 is required for conventional RS-232 voltage levels.

Always check the logic-voltage requirements of the target device before connection.

Do not assume the 5V power output means that every connected UART device is 5V-logic compatible.

Package Includes

1 × CP2102 Micro USB to TTL UART Serial Converter Module