Method and device for realizing a plurality of key functions by using single IO

Abstract

The invention provides a method for realizing a plurality of key functions by using a single IO. An IO interface is integrated in a key detection circuit, the key detection circuit further comprises aprocessor and a plurality of keys, one end of each key is respectively connected with resistors with different resistance values in series and then is connected with the IO interface, and one end, connected with the IO interface, of each key is connected with a power supply after being connected with a resistor in series, and the key detection method comprises the following steps: detecting the voltage of the IO interface and obtaining voltage parameters; when the voltage parameter reaches a first standard, configuring the IO interface to be in an output state; when the voltage parameter reaches a second standard, configuring the IO interface to be in an input state, and starting timing; when the voltage parameter reaches the first standard again, stopping timing, and obtaining a time parameter; and outputting the key value according to the numerical interval where the time parameter is located. Key value distinguishing is carried out by changing the state of the IO interface and detecting the voltage parameter change time length, and the function of expanding a plurality of keys by utilizing a single IO interface can be realized.

Description

technical field [0001] The invention relates to the technical field of electronic circuits, in particular to a method for realizing multiple button functions by using a single IO and a device for realizing multiple button functions by using a single IO. Background technique [0002] With the rapid development of electronic equipment, more and more signals need to be detected by the chip. [0003] Taking the button signal or status control signal as an example, the common IO interface expansion button methods mainly include stand-alone and matrix. The stand-alone button requires the chip to have enough IO interfaces, which are respectively connected to a button or a status control switch; matrix The keyboard is composed of row and column lines, and the keys are located at the intersection of the row and column lines, such as a 4*4 matrix, which controls 16 keys through 8 IO interfaces, 4 outputs and 4 inputs. [0004] However, for independent buttons, one IO interface can on...

AI Technical Summary

Problems solved by technology

[0004] However, for independent buttons, one IO interface can only expand one button. If you want to expand multiple buttons, you need multiple IO interfaces. The buttons occupy more IO interface resources, so you need to choose IO Chips with many interfaces are expensive; matrix buttons expand multiple buttons through multiple IO interfaces, which still occupy more IO interface resources

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