BUS SYSTEM INCLUDING BUS, AND MASTER DEVICE CONTRIBUTING TO STABILIZATION OF POTENTIAL LEVEL OF BUS IN NON-ACCESS TERM

摘要

PROBLEM TO BE SOLVED: To stabilize the potential level of a bus by driving the bus with a specified driving current so that data are transmitted to the bus when the system is non-access state and when a system in an access state and the data of a data hold part are to be written in a device. SOLUTION: An output data selection part 28 is equipped with two input terminals connected to an access data hold part 26, a dummy data hold part 29 and an output terminal connected to a drive circuit 32. When it is in an access term, data which the access data hold part 26 holds are outputted toward the input terminal of the drive circuit 32 in a multiple separation part 30. When it is in a non-access term, data which the dummy data hold part 29 holds are selectively outputted toward the input terminal of the drive circuit 32 in the multiple separation part 30. The drive circuit 32 continues dummy data which the dummy data hold part 29 in the non-access term and keeps on outputting them to a bidirectional bus.