| 摘要 |
PURPOSE:To perform bias temperature (BT) screening of higher reliability by setting a data part in an incorporated ROM to the non-execution state and executing only an instruction group. CONSTITUTION:When an address X is designated by an address register 16 and an instruction 1 is selected from a ROM cell part 15, it is taken into a instruction decoder (ID) 22 through an output circuit part 17 and an instruction register (IR) 21. The ID 22 detects the instruction at the time of input of the instruction 1 and outputs the detection signal to the S (set) terminal of the RS flip flop 23 through an instruction code detection signal line 25. This RS flip flop 23 receives this signal to output a level '0' signal, and this signal is supplied to an AND circuit in a control signal output circuit part 24 through an RS flip flop output line 27. Consequently, a one-chip microcomputer incorporating the ROM is set to the non-execution state and is kept in this state till execution of an instruction 2. Thus, effective BT screening is performed. |
