CP2102 is silab developed USB to serial chip, small size, may not require any peripheral components to reach into a simple USB-UART scheme, communication speed up to 1Mbps, it is easy to upgrade the product to the USB serial port, but Because of its small size, but it is also MLP package, welding has some technical difficulty, and therefore the owner designed this compact USB-UART module, leads to the interface includes a 5V, 3.3V, TXD, RXD, GND, which TXD, RXD directly MCU serial connection, convenient for debugging the initial product, even 3.3V system can also take power from this module (less than 100mA), LED display module powered on and operating normally.