| 摘要 |
PURPOSE:To detect previously degradation of functions of various logical elements of a data processing unit, by selecting plural control clocks from the generating means, which generates control clocks, by a selecting means and by controlling this selecting means by microinstructions. CONSTITUTION:Plural kinds of control clock CL0-CLn generated by a clock generating means are transferred to clock switching circuit 6, and one of clocks CL0-CLn is selected by circuit 6 and is output according to the control signal transferred from decoder 5. Information stored at the address of memory 2 is held in data register 3 by indication of data held in address register 1, and further, information held in register 3 is held in instruction register 4, and the instruction in information of register 4 is decoded by decoder 5. In case that this instruction is the switching instruction for control clocks, the switching control signal is transferred from decoder 5 to circuit 6, and one of clocks CL0-CLn is selected and output, so that functions of various logical elements of the data proccessing unit can be checked. |
