| 摘要 |
PURPOSE:To obtain a simulator for an I/O device by enabling to generate a specified dat word on the data bus of a microprocessor when a sealed memory mapped I/O device is accessed repeatedly. CONSTITUTION:The first RAM 64 is accessed by an address sent out from a microprocessor to be tested, and the second RAM 66 is addressed by data accumulated in the memory. Out of two data words, the first data word is outputted to the data bus of the microprocessor, and the second data word is supplied to the data input terminal of the first RAM 64. When the second data word differs from data words accumulated previously, the microprocessor sends out accumulated data to the first RAM 64 as a differential address to read a specific memory mapped I/O address.
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