| 摘要 |
PURPOSE:To perform self-evaluation by the use of a microcomputer manufactured for marketing, by providing a test multiplexer in said microcomputer. CONSTITUTION:When 0 is applied to external terminals TEST1-TEST4, an instruction code outputted from an ROM1 is applied through a test multiplexer 3 to an instruction register 4, which performs its original oepration. When 1 is applied to the TEST3, an external terminal SEG1-14 is connected to a segment bus S-BUS and a control bus L-BUS. In this state, when 1 is applied to the TEST1, the multiplexer 3 separates the ROM1, and the instruction code applied to SEGs 1-14 is stored in a register 4. When the TES3 is applied with 1 and the TEST4 is applied 1, the ROM1 does not operate and the contents of a program counter 2 are outputted to the SEGs 1-14. Further, when 1 is applied to the TEST3 and TESTs 1 and 2, an instruction is outputted from the ROM1 to the SEGs 1-14. |
