Transcription: A microprocessor built into the keyboard, such as the Intel 8048, constantly scans circuits leading to the keys. It detects the increase and decrease in current from the key that has been pressed. By detecting both an increase and a decrease in current, the processor can tell when a key has been pressed and when it's been released. Each key has a unique set of codes, even if to the users the keys seem identical. The processor can, for example, distinguish between the left and right shift keys. To distinguish between a real signal and an aberrant current fluctuation, the scan is repeated hundre ...
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