CH376S is used as a file manage control chip, used to MCU system read/write a file in USB Flash Drive or SD card. It supports USB-Device Mode and USB-HOST Mode. It also sets firmware of special communication protocol to deal with Mass-Storage devices, communication interface firmware of SD card, FAT16, FAT32 and FAT12 file system manage firmware in the inner. The CH376S Module can be used as an external storage device supporter/Medium to communicate with the microcontroller and the storage device. This module helps in maintaining storage problems like low memory while compiling the code.
The "CH376S USB read/write module" has a CH376S chip onboard which does most of the hard work for you. All you have to do is send the module some commands from the Arduino and the CH376S chip will do the rest. You can communicate with the module in three different ways:
When the CH376S USB module arrives in its package, it will have a jumper between the TXD pin and GND. You will need to remove this jumper to make the necessary connections between the Arduino UNO and the CH376S USB module.
Also, be aware that the CH376S USB module has an onboard LED just above the TXD and GND pins near the USB port. This LED will only turn on providing the CH376S module is in USB mode AND a USB device has been inserted into the USB port. Both conditions must be met before the module's onboard LED will illuminate. You will not see the LED turn on just by powering the board.
1 x USB Disk Read-write Module For Arduino CH376