If you want to connect a microcontroller via a USB cable, this board is what you need. This USB to TTL bridge is a module, base on CH340 series USB-TTL bridge, and it is a budget solution for connecting micro-controllers and other digital serial devices to PC. Direct access driver support is available www.wch.cn for the latest application notes and product support information for the CH340G. This board uses 5V signal levels by default. Also tolerance for 3.3V logic level signals. Board have power out for DC 5V and 3.3V. With limit of currency 500mA. USB to TTL CH340, 5V/3.3V - Serial Converter, with Micro USB socket. Logic level tolerance for 3.3V and 5V, not need switching. Base on USB converter IC CH340G, with frequency 12MHz.