CH341T 2in1 USB module USB to I2C IIC UART USB to TTL with selectable 5V and 3.3V outputs. Key features USB to UART Serial port data transmission and reception ISP mode program download for STC and STM series microcontrollers Serial data communication from 50 bps to 2 Mbps, with configurable baud rates including non standard values USB to I2C IIC I2C bus operation with flashing capability Master only operation Adjustable I2C speeds: 20K, 100K, 400K, 750K Serial to TTL adapter TTL level serial interface with LED status indicators Voltage switching terminal for convenient voltage selection Benefits and practical advantages Versatile multi protocol support in a single compact module Enables easy connection between USB hosts and microcontrollers or I2C devices Flexible baud rate and I2C speed options improve compatibility with a wide range of devices LED indicators provide quick, ataglance status during operation 5V and 3.3V output options simplify power compatibility with different targets Compatibility and scope Works with USB capable hosts for serial and I2C interfacing Suitable for STC and STM series microcontrollers in ISP mode Useful for flashing I2C flash chips and operating I2C devices in Master mode Size, form factor and performance notes Designed as a compact 2in1 module around the CH341T chipset Performance is defined by supported baud rates, I2C speeds, and master only operation for I2C Use scenarios Microcontroller programming and ISP downloads Connect the module via USB to a PC to program STC or STM microcontrollers using the USB to UART interface Utilize the USB to UART path for serial data communication across a wide baud range I2C device programming and flashing Use the USB to I2C path to communicate with I2C flash chips and other I2C devices Take advantage of the master mode and selectable speeds (20K/100K/400K/750K) for reliable flashing and device operations Serial to TTL bridging and debugging Convert USB serial data to TTL levels for microcontroller debugging Use the LED indicators to monitor connection and data activity Use the voltage switch terminal to match target device voltage requirements Notes The module provides 5V and 3.3V outputs to power or levelshift connected devices UART speed range includes standard and non standard baud rates for greater compatibility I2C interface is master only and supports common flash and peripheral devices along with flashing workflows This description preserves the product brand, model CH341T, its 2in1 USB to I2C IIC UART and USB to TTL functionality, the voltage outputs, the specified baud rate range and I2C speeds, the master only I2C operation, and the LED status feature, while presenting clear, practical use cases and benefits.