KEYBOARD CODING APPARATUS

摘要

The keyboard coding appts. couples to keys and comprises a scanning interface including a counter, a decoder and a multiplexer. The scanning interface, in response to each pulse received from a microprocessor through an input lead, sends to the microprocessor on an output lead a logic signal indicative of the state of any selected one of the keys. Whenever microprocessor sends a pulse to the scanning interface, it increments by one of the contents of an internal register and, before sending another pulse, processes the signal from the scanning interface.