| 摘要 |
PURPOSE:To evade a bad influence of an error control memory content upon other units, by invalidating the output of a control memory in diagnostic operation. CONSTITUTION:To diagnose unit 2 in a stop state by unit 1, the Q output of diagnostic mode FF12 is set to ''1'' via AND5 and the address of a control memory to be diagnosed is sent out via AND4, so that unit 2 will set the address to control memory address register 7. Then, information read out from control memory 8 is set to control memory latch register 9 and the Q output of FF12 changes into ''0''; and the microinstruction type assigning decoders is inhibited from operating to make all output ''0'' and control memory decoders 13 and 14 do not perform the control inside of the unit at all, so that parity check circuit 11 will check the control memory. By reading the parity check result by AND3, unit 1 completes the diagnosis of one word. Consequently, a bad influence upon other units can be avoided. |
