| 摘要 |
PURPOSE: A ROM emulator is provided to improve a processing speed and an extension characteristic by employing a transmission method using a printer port being a parallel transmission method. CONSTITUTION: Each ROM emulator includes a RAM of storing data, a data buffer, an address latch, and an expansion signal generator. The data buffer and the address latch temporarily store a data to a position between the RAM and a printer port, and temporarily stores a data to a position between the RAM and a target board. The expansion signal generator is connected in parallel to the printer port, includes a switch and a de-flip-flop connected to the switch in every ROM emulator board. The ROM emulator transmits a signal to a ROM emulator board having access state corresponding to a transmission signal from the printer port, and cuts off the signal to another ROM emulator board. Thereby, ROM emulator improves a processing speed and an extension characteristic by employing a transmission method using a printer port.
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