Patent ID: 8108591

Claim:
A semiconductor device comprising: a first interface which is capable of being connected to a memory card and communicating with the memory card, the memory card having a nonvolatile semiconductor memory and having an unlock state and a lock state, the memory card in the unlock state permitting an access to the nonvolatile semiconductor memory, the memory card in the lock state prohibiting the access; a second interface which is capable of being connected to a host device and communicating with the host device, the host device generating an access command to access the memory card; and a control unit which is connected to the first interface and the second interface, wherein the control unit, when the memory card is connected to the first interface, executes a first initialization processing of the memory card using a command which the memory card in the lock state is capable of recognizing and is sent from the host device through the second interface, the first initialization setting the memory card to a state which allows status data of the memory card to be read out, the control unit, when the first initialization processing succeeds, reads the status data from the memory card to determine whether the memory card is in the unlock state or the lock state, when the memory card is in the lock state, the control unit is set to a pass-through mode by a command sent from the host device, and in the pass-through mode, the control unit allows an unlock command to pass through the control unit to the memory card to release the lock state of the memory card.