| 摘要 |
PURPOSE: A key input system for preventing chattering and an operation method therefor are provided so that a response speed to a key input can be improved by maintaining the key input system to have a key scan allowing state in order to directly sense a key press operation due to an external operation. CONSTITUTION: A key(10) is pressed due to an external operation, for transmitting a special key scan value to the system. A programmable logic chip(60) reads the key scan value generated according to the key press operation, and simultaneously generates a control signal and an interrupt signal according to the frequency division of a clock signal. A clock source(31) is connected to the programmable logic chip(60), for generating a clock signal for controlling the system. A processor(50) senses the key press operation according to the interrupt signal from the programmable logic chip(60), and reads the key scan value to perform a key input function. Here, the programmable logic chip(60) includes a data latch(20) for reading the key scan value according to the key press operation, and outputting the key scan value through a data line(11) according to an external key scan signal, the first clock synchronizing unit(32) and the second clock synchronizing unit(33), a control signal generator(34) and a zero counter(40).
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