MCP2221 - Serial Number Configuration
The MCP2221 serial number can be configured using a utility available from the product page. You can choose to have the MCP2221 provide this serial number to the host during enumeration by having the 'Enumerate with serial number' box checked before hitting the Configure Device button. If this selection isn't made, the MCP2221 will indicate to the host that no serial number is available. This way, several MCP2221 devices can be plugged in (e.g., for testing) into the same USB port without the driver installation process being repeated every time.