To talk to a USB Pen Drive you need to have your microcontroller act as a USB host in place of a normal PC connection to the Pen Drive.

The CP2101 device is a "device end" end of a USB port that provides UART end point capability. It would only be useful as a means to quickly and easily be able to connect a microcontroller with a UART to a PC via a USB cable.

You would not be successful trying to use the CP2101 to talk to the USB Pen Drive!!

We get this type of subject here on the forum again and again wherein there is great confusion as to the way USB works. You need to get a good fundamentals book on USB and do some reading on the subject.

Making a USB "device" endpoint is a relatively easy project. Making the USB host end is a hard job. Until just recently it was near to impossible to anticipate having a microcontroller acting as the host end of a USB interface. But there has been discussion here on the forum recently that there are some new developments coming out of Cypress and Phillips that will be changing this so search here and learn more.

Michael Karas