| 摘要 |
PURPOSE:To give information on a fault through simple constitution by inverting and outputting a check code which is the output of an encoding circuit when an information selecting means has trouble. CONSTITUTION:Data transferred from processing units 1-4 to a processing unit 13 are inputted to a priority circuit 5 through REQ lines 0-3. One of requests for transfer inputted to a circuit 5 is selected according to selection condition determined by predetermined priority and stored in one of registers 6-9. The stored contents of the registers 6-9 are converted by the encoding circuit 10 into specific codes and check units are added thereto. If a fault occurs in, specially, the circuit 5 in this information selecting and converting circuit, namely, when the circuit 5 selects plural pieces of information or no information, the check code outputted by the circuit 10 is inverted and outputted to the unit 13. Consequently, an error is reported easily. |
