Patent ID: 8417864

Claim:
A cascade-able serial bus card device for coupling between a host device and a second serial bus card device, wherein the host device includes a serial bus interface, the cascade-able serial bus card device comprising: a first connection interface coupled to the serial bus interface of the host device; a second connection interface coupled to the second serial bus card device; and a bypassing module coupled to a CS (chip select) signal line of the serial bus interface and the second connection interface for receiving a CS signal and selectively bypassing or non-bypassing a CS signal according to a command sent by the host device, wherein when the CS signal is being non-bypassed, the bypassing module transmits the CS signal to the cascade-able serial bus card device such that the host device utilizes a first function provided by the cascade-able serial bus card device; when the CS signal is being bypassed, the bypassing module transmits the CS signal to the second serial bus card device via the second connection interface such that the host device utilizes a second function provided by the second serial bus card device; wherein the cascade-able serial bus card device and the second serial bus card device are both SD card devices; and wherein the sizes of the cascade-able serial bus card device and the second serial bus card device are substantially the same and the positions of the cascade-able serial bus card device and the second serial bus card device are interchangeable and an interrupt signal is sent to the host device for informing the host device when the second serial bus card device is plugged into the cascade-able serial bus card device or when a third serial bus card device is plugged into the second serial bus card device.