Virtual USB flash memory storage device with PCI express interface, controller and method thereof

A controller, coupled to a flash memory and a PCI Express connecting interface, wherein the PCI Express connecting interface is capable of being connected to a PCI Express bus disposed between a host and a flash storage device and provided for coupling the controller to the host, the controller comprising:

• a flash memory interface, for interfacing with the flash memory;
• a PCI Express interface, for interfacing with the PCI Express connecting interface;
• and
• a virtual USB module capable of receiving an instruction given by the host, the virtual USB module having an virtual USB host for receiving a USB instruction given by the host and an virtual USB device for executing the USB instruction, the virtual USB module being implemented by a firmware program to be executed by the controller,
• wherein when the flash storage device is connected to the host, the controller notifies the host that the controller is a USB host,
• wherein when the host reads data stored in the flash memory, the USB instruction given by the host is sent to the virtual USB module to be executed by the virtual USB module, and the data in the flash memory is converted by the flash memory interface or the PCI Express interface of the controller into a data format acceptable by the PCI Express bus, and then the converted data is sent to the host.

An apparatus, comprising:

• a microcontroller having a flash memory interface, a PCI Express interface, and a virtual USB module capable of receiving an instruction given by a host, the virtual USB module being implemented by a firmware program to be executed by the microcontroller;
• a flash memory coupled to the microcontroller for storing data;
• and
• a PCI Express connecting interface capable of being connected to a PCI Express bus disposed between the host and the apparatus and provided for coupling the microcontroller to the host;
• wherein when the apparatus is connected to the host, the microcontroller notifies the host that the apparatus is a USB storage device, and
• wherein when the host reads the data stored in the flash memory, a USB instruction given by the host is sent to and executed by the virtual USB module, and the data in the flash memory is converted by the flash memory interface or the PCI Express interface of the microcontroller into a data format acceptable by the PCI Express bus, and then the converted data is sent to the host.

A method for interfacing between a flash storage device and a host, the flash storage device comprising a PCI Express connecting interface, a flash memory and a controller interconnected therebetween, the PCI Express connecting interface capable of being connected to a PCI Express bus disposed between the host and the flash storage device and provided for coupling the controller to the host, the method comprising:

• notifying the host that the storage device is a USB storage device when the flash storage device is connected to the host;
• the host issuing a USB saving instruction to the flash storage device, the USB saving instruction being executed by the controller and data from the host for saving is converted by the controller into a data format acceptable to the flash memory and is stored in the flash memory;
• and
• the host issuing a USB reading instruction to the flash storage device, the USB reading instruction being executed by the controller, and the data in the flash memory is converted by the controller into a data format acceptable by the PCI Express bus, and then the converted data is sent to the host.