Keyboards, LCDs most widely used input/output devices of the 8051 Contents to be covered: keyboard fundamentals key press and key detection mechanisms Details of keyboard interfacing to
1 C1 R1 P2.0 P Key not pressed 1 C1 R1 P2.0 P Key pressed
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Keyboards organized in a matrix of rows and columns. The CPU accesses both rows and column through ports When a key pressed, a row and column make a connect; otherwise, there is no connection between row and column. Microcontroller scans the keys continuously to identify which one has been activated 4