A key detection circuit

Abstract

The invention discloses a key testing circuit. The key testing circuit has the advantages that the key identification performance is good, key circuits of the key testing circuit are in parallel connection, resistance values of all divider resistors are set reasonably, and a single chip microcomputer can judge keys accurately according to different input voltages; the robustness is good, and when a plurality of keyboard keys are pressed at the same time randomly, incorrect judgment is avoided; and the circuit is simple in structure, low in production cost and easy for large-scale production.

Description

technical field [0001] The invention relates to a key detection circuit, in particular to a resistance voltage division type keyboard key detection circuit. Background technique [0002] The basic principle of the resistor divider keyboard: use resistor divider to obtain different voltages, and the single-chip microcomputer identifies the keys according to the voltage value. When a button is pressed, the button detection circuit generates a fixed voltage value through the voltage dividing resistor and sends it to the A / D port of the microcontroller. By collecting the A / D value, it can be judged which button is pressed. The A / D value of different keys can be set by adjusting the resistance value. [0003] In the existing button detection circuit, resistors are usually connected in series. When multiple buttons are pressed at the same time, due to the voltage division of the resistors, they may be recognized as other buttons, thus causing misjudgment. Contents of the invent...

AI Technical Summary

Problems solved by technology

[0003] In the existing button detection circuit, resistors are usually connected in series. When multiple buttons are pressed at the same time, they may be recognized as other buttons due to the voltage division of the resistors, causing misjudgment.

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