Bus system and a master device that stabilizes bus electric potential during non-access periods

摘要

A master device in a system including a bidirectional bus and at least one device manages whether the system is in an access state in which the master device permits an access to or from one device or a non-access state in which the master device permits an access to none of the devices. The master device drives the bidirectional bus using a predetermined current to transfer data to or from one device connected to the bidirectional bus when the system is in the access state. When the state of the system changes from the access state to the non-access state, the master device drives the bidirectional bus in order to stabilize the potential of the bidirectional bus to keep the bus potential from changing when the system is in a non-access state, thereby eliminating the need for conventional pull-up/pull-down resistors for stabilizing the bus potential during a non-access state.