| 摘要 |
PURPOSE:To attain a recovery from a fault at the time of scan-out operation by a retrying method, etc., by constituting a scan-out register separately from the output holding register of a logic circuit. CONSTITUTION:Respective bit outputs of the logic circuit 1 are supplied to latches 2-5 constituting the output holding register 6 through 1st selecting circuits 7-10. The outputs of those latches 2-5 are supplied to latches 11-14 constituting a 1st back-end register through 2nd selecting circuits 19-22 and those are further supplied to latches 23-26 constituting a 2nd back-end register 27. The outputs f the latches 11-13 are supplied to circuits 8-10, the circuit 7 is connected to an external terminal, and the circuits 7-10 select and output one of two inputs. The outputs of the latches 23-25, on the other hand, are supplied to the circuits 20-22, the circuit 19 is connected to an external terminal 28, and the circuits 19-22 select and output one of two inputs. The output data of the logic circuit which is held in the register can be scanned out while being held. |
