INTERFACE CONTROL SYSTEM

摘要

PROBLEM TO BE SOLVED: To detect a bus stack and to prevent it by connecting a local bus monitoring timer directly to the input side of a local bus via a bus interface control part and outputting an error response from the local bus via a transmission control part when the timer has an overflow. SOLUTION: A local bus monitoring timer 16 is directly connected to the input side of a local bus 2 via a bus interface control part 1. Then the timer 16 is started not only by the command whose reception is decided by the part 1 but the bus start signal that is outputted to the bus 2, and the timer 16 is stopped by the transfer end signal that is outputted to the bus 2. When the timer 16 has an overflow, an error response is outputted from the bus 2 via a transmission control part 15b. As a result, the timer 16 can monitor not only the commands which are transmitted to a system bus but the commands that are executed via the bus 2 and with no intervention of the part 1.