| 摘要 |
PURPOSE:To provide the microcomputer which will not run away even when an undefined instruction is inputted, performs a trap operation by a single undefined instruction decoding circuit even with a plurarity of undefined instructions and capable to effectively use hardware added only for a test. CONSTITUTION:The microcomputer is provided with a constant generator 108 generating a trap code, an address generation part 106 supplying an instruction code as a part of the address of a test PROM 104 at the time of normal operation mode, and a selector 102 selecting an instruction code or trap code defined by a trap discrimination signal TRAP 121 from the test PROM 104 and outputting it to a control part 103. |
