A keyboard scanning circuit and control method thereof are provided. The method is adapted to detect states of a plurality of switching circuits arranged in an array manner, wherein each of the switching circuits includes a key switch and a first resistor connected in series; the switch circuits are coupled to a plurality of scan lines and a plurality of feedback lines; each of the scan lines is coupled to the switch circuits of the same column in a first direction, and each of the feedback lines is coupled to the switch circuits of the same row in the second direction.

A method for scanning a keyboard circuit is provided. The keyboard circuit includes a keyboard array, output wires, input wires, and a scanning circuit. Each of the output wires is electrically coupled to a corresponding column of key units of the keyboard array, respectively. Each of the input wires is electrically coupled to a corresponding row of key units of the keyboard array, and is provided with a pull-up resistor. The method includes: turning on and connecting open-drain transistors to the ground in a scanning interval to clean charges on the output wires; turning on the open-drain transistors and connecting the open-drain transistors to the ground sequentially in a scanning duration; and receiving detected electrical levels through the input wires, and when one of the detected electrical levels is substantially equal to the electrical level of the ground, determining that the corresponding key unit is pressed.

A method for scanning a keyboard circuit is provided. The keyboard circuit includes a keyboard array, output wires, input wires, and a scanning circuit. Each of the output wires is electrically coupled to a corresponding column of key units of the keyboard array, respectively. Each of the input wires is electrically coupled to a corresponding row of key units of the keyboard array, and is provided with a pull-up resistor. The method includes: turning on and connecting open-drain transistors to the ground in a scanning interval to clean charges on the output wires; turning on the open-drain transistors and connecting the open-drain transistors to the ground sequentially in a scanning duration; and receiving detected electrical levels through the input wires, and when one of the detected electrical levels is substantially equal to the electrical level of the ground, determining that the corresponding key unit is pressed.

A method for scanning a keyboard circuit is provided. The keyboard circuit includes a keyboard array, output wires, input wires, and a scanning circuit. Each of the output wires is electrically coupled to a corresponding column of key units of the keyboard array, respectively. Each of the input wires is electrically coupled to a corresponding row of key units of the keyboard array, and is provided with a pull-up resistor. The method includes: turning on and connecting open-drain transistors to the ground in a scanning interval to clean charges on the output wires; turning on the open-drain transistors and connecting the open-drain transistors to the ground sequentially in a scanning duration; and receiving detected electrical levels through the input wires, and when one of the detected electrical levels is substantially equal to the electrical level of the ground, determining that the corresponding key unit is pressed.

A keyboard scanning circuit and control method thereof are provided. The method is adapted to detect states of a plurality of switching circuits arranged in an array manner, wherein each of the switching circuits includes a key switch and a first resistor connected in series; the switch circuits are coupled to a plurality of scan lines and a plurality of feedback lines; each of the scan lines is coupled to the switch circuits of the same column in a first direction, and each of the feedback lines is coupled to the switch circuits of the same row in the second direction.

A keyboard scanning circuit and control method thereof are provided. The method is adapted to detect states of a plurality of switching circuits arranged in an array manner, wherein each of the switching circuits includes a key switch and a first resistor connected in series; the switch circuits are coupled to a plurality of scan lines and a plurality of feedback lines; each of the scan lines is coupled to the switch circuits of the same column in a first direction, and each of the feedback lines is coupled to the switch circuits of the same row in the second direction.

A keyboard device applicable to various kinds of applications with high responsivity is provided. The keyboard device includes keys to which key addresses are assigned and a memory in which data for determining whether a key has been depressed is writable and readable at an memory address corresponding to each of the key addresses. The device also includes a key capacitance detecting unit to detect a capacitance of the key corresponding to a selected key address, a capacitance-voltage converting unit to convert the capacitance of the key detected by the key capacitance detecting unit into a voltage, a data converting unit that reads threshold data in the memory address in the memory corresponding to the key address that is selected to convert the threshold data into analog data, and a depression determining unit that compares the analog data with the voltage to determine whether the key has been depressed.

A keyboard device applicable to various kinds of applications with high responsivity is provided. The keyboard device includes keys to which key addresses are assigned and a memory in which data for determining whether a key has been depressed is writable and readable at an memory address corresponding to each of the key addresses. The device also includes a key capacitance detecting unit to detect a capacitance of the key corresponding to a selected key address, a capacitance-voltage converting unit to convert the capacitance of the key detected by the key capacitance detecting unit into a voltage, a data converting unit that reads threshold data in the memory address in the memory corresponding to the key address that is selected to convert the threshold data into analog data, and a depression determining unit that compares the analog data with the voltage to determine whether the key has been depressed.

An amending circuit of correcting bouncing misjudgment of a keyswitch includes a comparing unit, a predetermined voltage generating unit and a controlling unit. The comparing unit has a first input terminal, a second input terminal and an output terminal. The first input terminal is adapted to receive a triggering signal generated by the keyswitch. The predetermined voltage generating unit is electrically connected to the second input terminal and adapted to generate a first predetermined voltage. The controlling unit is electrically connected to the output terminal. The controlling unit is adapted to determine whether to execute polling application according to a comparison result of the comparing unit, and to generate a confirming signal while a polling result of the polling application is kept at a specific level. The confirming signal is used by an external processor to confirm that the keyswitch is actually triggered.

An amending circuit of correcting bouncing misjudgment of a keyswitch includes a comparing unit, a predetermined voltage generating unit and a controlling unit. The comparing unit has a first input terminal, a second input terminal and an output terminal. The first input terminal is adapted to receive a triggering signal generated by the keyswitch. The predetermined voltage generating unit is electrically connected to the second input terminal and adapted to generate a first predetermined voltage. The controlling unit is electrically connected to the output terminal. The controlling unit is adapted to determine whether to execute polling application according to a comparison result of the comparing unit, and to generate a confirming signal while a polling result of the polling application is kept at a specific level. The confirming signal is used by an external processor to confirm that the keyswitch is actually triggered.