CN1055358C - Device and method for keyboard scanning and additional input detection - Google Patents

Abstract

The invention relates to a device and method for keyboard scanning and additional input detection. By connecting or not connecting resistors between the existing input/output ports, various functions can be selected without increasing the number of ports and without affecting the original keyboard scanning function. And the additional input function will be automatically detected each time a key on the keyboard is pressed, that is to say, the additional input function can be changed between each key input, so that the application of the input function is more extensive.

Description

Device and method for keyboard scanning and additional input detection

The invention relates to a device and method for keyboard scanning and additional input detection. In each country, the specifications of the telephone system are set differently. Please refer to Table 1. The specifications listed in Table 1 are actually used in telephone dial-up circuits. The specifications in Table 1 are selected as shown in Table 1. As shown in Figure 2, if various specifications can be selected in the same telephone dialer circuit, several input ports must be added so that the state of function key setting can be detected. However, because the packaging cost of an integrated circuit is directly related to the number of pins (that is, the number of ports), refer to Table 3. Generally speaking, the more pins, the higher the packaging cost, so reducing the size of the integrated circuit It is one of the goals that manufacturers and designers strive to pursue without affecting the pin position of the integrated circuit, or retaining the original pin position of the integrated circuit to improve its function.

In the prior art, about the technology of keyboard scanning and additional input function detection circuit, you can refer to the Taiwan patent "keyboard scanning and selection circuit" (Case No. 79206648). The method used is to make the oscillator start after POWER-ON Oscillation and the start detection circuit detects the state of mutual connection of resistances between the input/output ports, and then enters the normal working mode. This method utilizes the way of connecting or not connecting resistors between the existing keyboard input/output ports to add additional input functions. Although it can achieve the purpose of saving integrated circuit pins, there are at least two disadvantages: the first First, this kind of keyboard scanning and selection circuit is to detect the connection status of the external resistance of the port when POWER-ON, but if the system power supply is unstable, it may not be able to detect or detect errors; second, this kind of keyboard scanning and selection circuit The additional input function can only be detected within a period of time after the initial POWER-ON. In the rest of the time, if the state of the additional input function changes, it cannot be detected.

The purpose of the present invention is to improve the above-mentioned shortcomings in the prior art, and provide a device method for keyboard scanning and additional input detection, which can achieve the effect of increasing input control without increasing the pin position of the integrated circuit. The change of the additional input function can be detected stably in real time, which can save costs and expand the scope of application.

种选择。同时，在本发明的键盘扫描及附加输入检测的装置及方法是在每次按下键盘上的按键时均自动检测附加输入功能，亦即，附加输入功能可在每次按键输入间变化，而使得输入功能的应用更为广泛。The method of the present invention utilizes the mode of connecting or not connecting resistors between the existing input/output ports, without increasing the number of ports and without affecting the original keyboard scanning function, various functions can be selected, for example In other words, on a M ^* N matrix keyboard can be added

options. At the same time, the device and method for keyboard scanning and additional input detection of the present invention are to automatically detect the additional input function when pressing a button on the keyboard each time, that is, the additional input function can be changed between each key input, and This makes the application of the input function more extensive.

The technical scheme of the present invention is: a method for keyboard scanning and additional input detection, which uses existing input/output ports to detect whether there is a resistance between the input/output ports of each column and between the input/output ports of each row, so as to Adding an input function, the method includes the following steps:

(i) suspending the operation of the one-key scanning circuit used to scan the keyboard for a period of time each time a key is pressed on the keyboard;

(ii) During the pause time, detect whether there is a connection between the input/output ports of each column and between the input/output ports of each row through resistance, and input the detected potential information into a storage In the device, it is used to judge whether the row input/output ports and the column input/output ports are connected to each other through resistors;

(iii) Stop detecting whether the ports are connected to each other via resistors, and make the key scanning circuit continue to scan the keyboard.

A device for keyboard scanning and additional input detection, comprising:

Clock pulse generator, used to generate various control clock pulse signals;

a column input/output port for transmitting a signal for scanning the column position of a key on the keyboard;

A row input/output port for transmitting a signal for scanning the row position of a key on the keyboard;

a key scanning circuit, the key scanning circuit detects the row and column position of a pressed key on the keyboard via the column input/output ports and the row input/output ports respectively according to the clock pulse signal generated by the clock pulse generator;

an additional input detection circuit, the additional input detection circuit detects between the column input/output ports through the column input/output ports and the row input/output ports respectively according to the control clock pulse signal generated by the clock pulse generator and whether there are resistors connected to each other between the row input/output ports;

A plurality of storage devices are used to record the row and column position information of the pressed key scanned by the key scanning circuit and the resistance connection status information between ports detected by the additional input function detection circuit.

In order to enhance the understanding of the present invention, the preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings.

Fig. 1a is the plane view of a typical 4 ^* 3 matrix keyboard;

Fig. 1 b is one of the circuit diagrams of the key scanning circuit of the 4 ^* 3 matrix keyboard shown in Fig. 1 a;

Fig. 1c is a clock pulse diagram controlling the action of the key scanning circuit shown in Fig. 1b;

Figure 2a is a circuit diagram of a circuit that can detect whether there is a circuit connected between integrated circuit ports;

Fig. 2 b is a clock pulse diagram controlling the action of the key scanning circuit shown in Fig. 2 a;

Fig. 3 a is a circuit diagram of keyboard scanning and additional input detection device of the present invention;

Fig. 3b is a timing diagram for controlling the operation of the circuit shown in Fig. 3a.

The methods of keyboard scanning and additional input detection related to the present invention will be described below using the circuits shown in FIG. 1b and FIG. 2a respectively.

Referring to Figures 1a to 1c, it is a key scanning circuit of a known 4 ^* 3 matrix keyboard, and the system is controlled by four clock pulse signals S1 to S4 to work repeatedly in sequence. Initially, when the clock pulse S1 is high, the column I/O ports R1 to R4 are all at high potential with high impedance, and the row I/O ports C1 to C3 are at low potential with relatively low impedance. If any key is pressed, one of the column input/output ports R1 to R4 will be reduced to a low potential, and at the end of the high potential of the clock pulse S2, the potentials of the column input/output ports R1 to R4 will be respectively Latching with latching elements 10a to 10d. Immediately after the clock pulse S3 is at a high potential, the scanning state is changed so that the column input/output ports R1 to R4 are at low potential with lower impedance, while the row input/output ports C1 to C3 are at high potential at high impedance, and at At the end of the high potential of the clock pulse S4, the potentials of the row input/output ports C1 to C3 are latched by the latch elements 20a to 20c, respectively. Repeat the above-mentioned action of alternately scanning the keyboard several times, if one of the column latch elements 10a to 10d is fixed as a low potential, and one of the latch elements 20a to 20d is also fixed as a low potential, then it can be used to confirm the pressed button. The row and column position of the key.

Referring to Figures 2a and 2b again, Figure 2a is a circuit that can detect whether there is a resistor connected between the ports of an integrated circuit, and Figure 2b is a clock pulse diagram for controlling this circuit, where Rm and Rn are two input/outputs of the integrated circuit port, S1 and S2 are clock pulse control signals. Its working method is to use NMOS to pull the potential of the Rm port to zero potential when the clock pulse S1 is at a high potential, and then use the PMOS to pull the potential of the Rn port to the power supply potential when the clock pulse S2 is at a high potential. When the high potential of the pulse S2 ends, the potential of the Rm port is locked by the latch element 30 . At this time, if a resistor is connected between the Rm port and the Rn port, the potential of the latch element 30 is high; however, if no resistor is connected, the potential of the latch element 30 is low. That is, it can be judged whether there is a resistor connected between the Rm port and the Rn port according to the output potential of the latch element 30 . Then judge the setting of various input functions according to the different states of whether there is a resistor connected between the ports.

And because the touch switch of the keyboard is mechanical, so when the key is just pressed, there will be an unstable bounce, causing the potential in the initial latch element to be unstable, that is, bouncing noise (bouncing noise) will be caused. The position of the pressed key cannot be confirmed until the bouncing noise disappears and the potential of the latch element stabilizes. Generally speaking, the waiting and confirmation time is at least tens of milliseconds. The present invention makes full use of this section of waiting time, and in this section of time, the key scanning action of the keyboard is suspended for a short period of time, and an additional input detection circuit is used to detect the connected state of the resistance between each input/output port. Each time the key is input, the setting state of the additional input function can be effectively detected at the same time, so as to achieve the purpose of expanding the input function. It should be noted that this small period of time for detecting the additional input function can be located in any period of the waiting period.

The working modes of the keyboard scanning circuit and the additional input detection circuit of the present invention have been respectively described above. Next, a preferred embodiment of the keyboard scanning and additional input detection device of the present invention will be described. See Figure 3a, as shown. The keyboard scanning and additional input detection device of the present invention includes a clock pulse generator (not shown in the figure), and this clock pulse generator is used to generate various control clock pulse signals; Column input/output ports Rm and Rn are used for Transmit the signal of the column position of the key on the scanning keyboard; row input/output ports Ci and Cj, in order to transmit the signal of the row position of the key on the scanning keyboard; key scanning circuit 60; additional input detection circuit 70; The storage devices 40a-40c and 50a-50c, wherein, each time a key is input, the control signal "SKIP" will be generated to control the operation of the key scanning circuit 60 or the operation of the additional input detection circuit 70, that is, when SKIP is logic "0" ", the key scanning circuit 60 works to confirm the position of the input key; and when SKIP is logic "1", the output of the key scanning circuit 60 is stopped, and the additional input detection circuit 70 works to detect each key on the keyboard. The status of resistor connection between input/output ports.

Referring to FIG. 3b again, the working mode of the circuit of the present invention is shown in the timing diagram of FIG. 3b. Usually SKIP is logic "0" to make the key scanning circuit 60 work, so as to detect the key state of the keyboard. Whenever there is a key input, then during the period when the key is pressed, the work of the key scanning circuit 60 is suspended for a short period of time, and in this small period of time, SKIP is logic "1", so that the key scanning circuit 60 has no Any output, meanwhile, memory device 40a, 40c, 50a and 50b also do not accept the signal of any input/output port, but detect between column input/output port Rm and Rn and row input/output port with additional input detection circuit 70 Whether there is a resistance connection between Ci and Cj and when the high potential of the clock pulse S2 ends, the detection result of the resistance connection state between the column input/output ports Rm and Rn is recorded in the storage device 40b, and at the end of the clock pulse S4 When the high potential ends, the detection result of the resistance connection state between the row input/output ports Ci and Cj is recorded in the storage device 50c, and then SKIP returns to logic "0", and the key scanning work of the keyboard is continued. In addition, the SKIP signal can become a logic "1" when a key is pressed on the keyboard, or become a logic "1" when the pressed key is released, or can be turned into a logic "1" when a key is pressed. It becomes logic "1" at any time during a period of time until the key position is confirmed.

Finally, it must be explained that because a column input/output port and a row input/output port are short-circuited during key input, it is impossible to achieve resistance connection between the column input/output port and the row input/output port. The purpose of increasing the input function. Also, the memory device used in the embodiment of the present invention may be constituted by a latch element.

Although the present invention is described above with a preferred embodiment, it is not intended to limit the present invention, and the protection scope of the present invention should be limited by what is defined in the claims.

Table I Telephone Communication Specifications type ADial Rate Selection (Dial Rate Sl st)BContinuation/Break Ratio (Make/Break′Ratio)CPause (Pause)DMomentary Break (Flash)EDialing Pulse (Dialing Pulse) Ten pulses per second or twenty pulses per second (10PPS or 20PPS) 1:2 or 2:32 seconds to 4 seconds 80ms to 600ms normal or n+1 or 10-n push dial Number of sent pulses Normal n+1 10-n 0123456789 10 1 101 2 92 3 83 4 74 5 65 6 56 7 47 8 38 9 29 10 1

Table II Specification Way ADial rate selection BContinuation/discontinuation ratio CPauseDMomentary disconnectionEDial pulse Use one input port to choose 10PPS or 20PPS Use one input port to choose 1:2 or 2:3 fixed for 3.6 seconds When the on/off ratio = 1:2, choose 100ms When the on/off ratio = 2:3, choose 600ms to fix in normal

Table three Port (Pin) Package (Package) Price (NT) 16182022 2.53.24.35.4

Claims (5)

1. A method for keyboard scanning and additional input detection, using the existing input/output ports to detect whether there is resistance between the input/output ports of each column and between the input/output ports of each row, so as to increase the input function. The method includes the following steps: (i) suspending the operation of the one-key scanning circuit used to scan the keyboard for a period of time each time a key is pressed on the keyboard; (ii) During the pause time, detect whether there is a connection between the input/output ports of each column and between the input/output ports of each row through resistance, and input the detected potential information into a storage In the device, it is used to judge whether the row input/output ports and the column input/output ports are connected to each other through resistors; (iii) Stop detecting whether the ports are connected to each other via a resistor, and make the key scanning circuit continue to scan the keyboard. 2. The method for keyboard scanning and additional input detection as claimed in claim 1, characterized in that, from when a key is pressed on the keyboard to confirming the position of the pressed key in the storage device, it is necessary to A period of waiting time, and the period of time used to detect whether the ports are connected to each other via a resistor can be any period of time during this period of waiting time. 3. The method for keyboard scanning and additional input detection as claimed in claim 1, characterized in that, when a key is pressed on the keyboard, the key scanning circuit continues to scan the keyboard, and when the pressed key is released, When the key is pressed, the output of the key scanning circuit is stopped, and at the same time, it starts to detect whether the ports are connected to each other through resistors. 4. A device for keyboard scanning and additional input detection, comprising: Clock pulse generator, used to generate various control clock pulse signals; a column input/output port for transmitting a signal for scanning the column position of a key on the keyboard; A row input/output port for transmitting a signal for scanning the row position of a key on the keyboard; a key scanning circuit, the key scanning circuit detects the row and column position of a pressed key on the keyboard via the column input/output ports and the row input/output ports respectively according to the clock pulse signal generated by the clock pulse generator; an additional input detection circuit, the additional input detection circuit detects between the column input/output ports through the column input/output ports and the row input/output ports respectively according to the control clock pulse signal generated by the clock pulse generator and whether there are resistors connected to each other between the row input/output ports; A plurality of storage devices are used to record the row and column position information of the pressed key scanned by the key scanning circuit and the resistance connection status information between ports detected by the additional input function detection circuit. 5. The device for keyboard scanning and additional input detection as claimed in claim 4, wherein the storage devices are formed by latch circuits.

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