公开(公告)号：JPH07168732A

公开(公告)日：1995-07-04

申请号：JP14450394

申请日：1994-06-27

Applicant: TANDEM COMPUTERS INC

Inventor： JIEFURII EI SUPURAUSU ,  UORUTAA II GIBUSON

IPC: G06F11/22 ,  G01R31/3185 ,  G06F11/267 ,  G06F11/27 ,  G06F13/00 ,  G06F13/36

Abstract: PURPOSE: To provide a digital system provided with many digital sub systems connected with each other by a shared bus structure mutually exclusively accessible so as to communicate data among the digital sub systems. CONSTITUTION: The system 10 is constituted so as to be tested by a pseudo random scanning test method. The respective sub systems 12a-12n are provided with a counter for supplying enable signals to the bus access or driver circuit constitution of the corresponding sub systems during a scanning test period. A scanning test operation is preceded by pre-loading the respective counters in a prescribed state and only one digital sub system drives a shared data bus 14 first and through the test period. Respective scanning sequences clock the counter once, the new sub system can drive the bus 14 in the next sequence and the bus access circuit constitution of the respective sub systems and the bus itself are tested.