| 摘要 |
PURPOSE:To confirm the operation of an incorporated memory part without preliminarily including a checking program in programs and to improve the reliability of a device by providing a bidirectional buffer and a buffer control part, etc. CONSTITUTION:At the time of testing a working memory 4, an external bus 31 or the like and bidirectional buffers 7, 8, and 9 are used to supply a write access signal, etc., from an external test equipment to corresponding internal busses 21, 22, and 23. A buffer control part 10 controls the bidirectional buffer 9 inward in accordance with the input signal. Then, the incorporated working memory 4 is easily accessed by the external test equipment. Consequently, the operation of the memory 4 is easily confirmed from the external without preliminarily including the checking program in programs of a computer 1. Thus, the yield or the like of a device, which cannot be replaced after the microcomputer 1 is installed once, like an IC card is improved, and the reliability of this device is improved. |
