JPS61208527A - Input device - Google Patents

Abstract

PURPOSE:To obtain an input device which can improve the overall processing efficiency of a system by processing the data on the chattering and the noise elimination synchronizing with the interruption signal of a fixed period interval. CONSTITUTION:When the interruption signal of a fixed period is supplied from a clock oscillator 9, a CPU 1 reads the data C of this time from a keyboard 3. Then the data KS of the preceding time which is read previously by the period and the processing data of the preceding time which is obtained by processing the data KS are read out of a main memory RAM 7. These preceding data are converted into the processing data G by means of equation I. Then the switch operating signal J which is actually delivered to outside is obtained from equation II by means of the data G and delivered via an I/O interface 8. Thus the normal switch operating signal is delivered in the next period when a normal switching action different from the chattering or noises is carried out.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an input device such as a keyboard having a switch mechanism operated by a person, and in particular to an input device that prevents malfunctions caused by noise or chattering phenomenon during operation. Regarding input devices.

[Prior art] For example, electronic typewriter-1 electronic cash register,
In a keyboard used as an input device for inputting various data into a personal computer or the like, switches (contacts) corresponding to each key are connected and wired in a matrix. Then, key scanning signals whose phases are slightly shifted from each other are inputted from input terminals in a vertical column connected and wired in a matrix, and each key signal is outputted from each output terminal in a horizontal row connected and wired in a matrix. (
switch status signal). When a certain arbitrary key is manually operated, a key scanning signal of the column to which the key belongs appears in the key signal of the horizontal column to which the key belongs. Therefore, the CPLI connected to this keyboard
A control unit such as the above is capable of specifying a key that has been manually operated.

In general, in input devices using such keyboards, when a person operates a key with his/her finger, the switch (contact point) that is linked to the key may cause a chattering phenomenon at the moment the key is started to be pressed or the moment the finger is released from the key. Cheap.

Also, high frequency noise (noise) may be present in the output key signal.
often occurs. A problem arises in that the control section determines that a high frequency fluctuation in the key signal caused by chattering or noise indicates that the key has been operated normally.

Normally, in order to avoid the above-mentioned problems, when fluctuations occur in the key signal due to regular key operations or the above-mentioned chattering or noise, this state is memorized and the state of the key signal is checked again after a certain delay time has elapsed. It is determined that the fluctuation is caused by a normal key manual operation only when it matches the state stored in .

[Problems to be Solved by the Invention] However, even with the above-mentioned input device that determines that a key signal is a legitimate key signal after a certain delay time has elapsed after a key is manually operated, the following problems still exist. Ta. That is,
The delay time is set to a considerably long value because it needs to be set longer than the expected maximum period of chattering and noise. Further, a control unit such as a CPU needs to determine whether the key signal matches or does not match the key signal after a certain delay time has elapsed. Therefore, the time delay from when a key is manually operated until the control unit determines that the key signal is a legitimate key signal becomes even larger.

If the time delay increases in this way, for example, if a key is manually operated during a period when external interrupt processing is prohibited, the execution of the above interrupt processing will take a long time, reducing overall processing efficiency. A problem arises.

Generally, among the keys on the keyboard of an electronic typewriter, there are keys such as the space key and the underline key that have a high probability of being repeatedly manually operated. In such a case, there is a concern that the judgment of the control wJ section may not be able to keep up with the speed of repeated manual key operations.

The present invention has been made based on the above circumstances, and its purpose is to perform data processing to eliminate chattering and noise in synchronization with interrupt signals at constant periodic intervals, thereby reducing switch input operations. It is an object of the present invention to provide an input device that can shorten the time required to output a regular switch operation signal and improve the processing efficiency of the entire system including the tiIJIm device connected to this device.

[Means for solving the problem] In the input device of the present invention, the switch state corresponding to the switch operation state output from the switch mechanism in synchronization with the interrupt signal TM at constant periodic intervals output from the timer circuit. a data reading means for reading the signal as data; a previously read data memory for storing the previous data KS read in the previous cycle of the interrupt signal TM by the data reading means; and a data processing for the previous data KS. A previous processing data memory is provided to store the previous processing data D obtained in the previous processing. Then, the logical product A and the logical sum R of the current data C read this time by the data reading means and the previous data KS stored in the previously read data memory are calculated, and furthermore, the logical product A and the previous processed data D are calculated. Find the logical sum,
The logical product value of this calculated logical sum and the logical sum R is set as the current processing data G. The exclusive OR H of the currently processed data G and the previously processed data D obtained by this data processing means is calculated, and this exclusive OR H and the currently processed data G are calculated.
The logical product J is calculated, and this logical product J is output as a switch operation signal.

[Operation] If the input device is configured in this way, the interrupt signal TM
The current data C read in synchronization with an arbitrary cycle is calculated using the following equation from the previous data KS read in the previous cycle and the previous processed data D obtained by processing this previous data KS. This time, it is converted into processed data G.

G= ([Canct KS] orD) and
E CorKS ]Furthermore, the switch operation signal J actually outputted to the outside is expressed by the following equation using this current processing data G.

J = ([GexorD] and G) Therefore, when a normal switch operation without chattering or noise is performed, a normal switch operation signal J is output in the next cycle.

F Example An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a schematic configuration of an input device according to an embodiment, and 1 in the figure is a CPU that performs various information calculation processes.
(Central processing unit). This CPU1 is pass line 2
A decoder 4. sends each key scanning signal SO to SN to the keyboard 3 serving as a switch mechanism via a decoder 4. T10 port 5.7 is input to each key signal KO= as each switch status signal output from this keyboard 3. ROM6 for storing fixed data such as control programs. A RAM 7 for temporarily storing variable data such as data input from the keyboard 3. and controls the ■/○ interface 8 etc. connected to external control equipment. Incidentally, a clock (CLK) oscillator 9 as a timer circuit that outputs an interrupt signal TM of a constant period To is connected to the interrupt input terminal of the CPU 1.

As shown in FIG. 2(a), the keyboard 3 has contacts (switches) 10 corresponding to each key arranged on the keyboard 3 in the form of (8 (rows) x [N11] (columns)). ), and <N+1 of this matrix
) column, one end of each contact 10 belonging to each column receives key scanning signals So to S of the decoder 4 via a common inverter 11.
Connected to the output terminal of N. Further, the other end of each contact 10 belonging to each of the eight rows of the matrix is connected to each input terminal of the T10 port 5 via a common inverter 12. Further, the input side terminals of each of the inverters 12 are connected to a control power source of 5cm via a resistor 13, respectively.

Further, as shown in FIG. 2(b), a diode 14 for preventing backflow is inserted in series with each contact 10.

As shown in FIG. 3, each data of the key signal input to the T10 port 5 in the previous cycle of the interrupt signal TM from the clock oscillator 9 at constant intervals To is stored as previous data KS in the RAM 7. Previously read data memory RAI to be stored.

A previously processed data memory RA2 is formed that stores previously processed data D obtained by data processing the previous data KS during the previous cycle. The previously read data memory RA1 and the previously processed data memory RA2 each have 8X (N+-0-1) data storage areas corresponding to the contacts 10 arranged in a matrix.

When the CPU 1 receives an interrupt signal TM from the clock oscillator 9 at regular intervals To, the CPU 1 sends the key scanning signals So to SN with a period To with a pulse width T1 to each other (N+1) via the decoder 4, as shown in FIG. It is sent to the input terminals of each row of the keyboard 3 with a phase shift of '/To. Also,
The CPtJ1 sends a data read command for each key signal Kn~7 to the T10 port 5 at the timing when each key scanning signal SO~8N output from the decoder 4 becomes H level.

Therefore, when the interrupt signal TM of period TO is input, the key scanning signal S is input within the first period T1 of period To.
Data indicating the open/closed state of each of the eight contacts 10 in the first row to which o is applied is read at once.

Similarly, data of each contact 10 in the second column is read within the next T1 period. Therefore, all data of each contact 10 in the (N+1> column) is read within the constant cycle To period included in the interrupt signal @TM.

Figure 5 shows a read at T10 port 5 in this way.
It is a flowchart which shows the data processing which CPU1 performs within this cycle TO period with respect to arbitrary one data among x (N+1) pieces of data. Note that the previous read data memory RAI of the RAM 7 stores the previous data KS that has already been read within the cycle To immediately before the interrupt signal TM, and the previously processed data memory RA2 stores Similarly, previously processed data D that has already been processed within the previous cycle To is stored.

That is, when the interrupt signal TM from the clock oscillator 9 is input to the interrupt input terminal at Pl, the H or L level value of the key signal KS of the row to which the relevant key belongs is read at R2 via the I10 port 5. This time we will call this data C. R3
The previous data KS of the corresponding key is read from the previous read data memory RAI. Then, the logical product A of the previous data K S read in R4 and the current data C read in this period To is calculated. Data C this time at R5
and the previous data KS. When the calculation of the logical product A and the logical sum R is completed, the current data C read in the current period To is stored in the data storage area of the corresponding key of the previous read data memory RA1 as the previous data KS in R6. That is, the previous read data memory RAI
Updates will be carried out.

When the data update of the previously read data memory RA1 is completed, the previously processed data D of the corresponding key is read from the previously processed data memory RA2 at Pl. Then, in R8, the logical product A and the previously processed data D are obtained.

Current processing data G shown by the following formula is calculated from the logical sum R.

G=[AorD and [R] When the calculation of the currently processed data G is completed, the exclusive OR H of the currently processed data G and the previously processed data D calculated in R9 is determined. Then, the logical product J of the exclusive OR H obtained in Plo and the currently processed data G obtained earlier is obtained, and the logical product J is calculated in Pll as the data of the operation signal of the corresponding key operated (switch operation signal) via the I10 interface 8. Finally, at Pl2, R
The current processing data G obtained in step 8 is stored as the previous processing data D in the data storage area of the corresponding key in the previous processing data memory RA2.

The data processing for the current data C in the current data C is completed.

FIG. 6 is a time chart showing the state of data processing executed according to the process shown in the flow chart of FIG.

That is, P in the figure is a contact state characteristic indicating the on/off state of the contact 10 corresponding to the key operation of the corresponding key, and the R1 region of this contact state characteristic P indicates the fluctuation due to chattering immediately before the key input operation, The R2 region shows the state in which the key is kept pressed, and the R3 region shows the fluctuation due to chattering immediately before the key is released.

Furthermore, R4 and R5 show fluctuations due to noise.

The waveform of the current data C read at the I10 port 5 every time the interrupt signal TM of period M T n is input is naturally one cycle longer than the waveform of the previous data KS read every cycle To from the previous read data memory RAI. The waveform is advanced by To. Therefore, the waveform of the logical product A of the current data C and the previous data KS becomes H level in the second period (after time t1) when the contact state characteristic P maintains the same state for 2To periods.

Furthermore, the waveform of the logical sum R of the current data C and the previous data KS is a cycle that is one cycle after the chattering start cycle of R1 (after time t2) of the contact state characteristic and the chattering end cycle of R3 (before time t3) Period up to H
level.

Furthermore, the waveform of the currently processed data G obtained at R8 in FIG. As a result, the signal is at H level during the period from time t1 to time t3.

Therefore, this current processing data G waveform becomes a regular contact state signal obtained by removing chattering and noise from the contact state signal P.

In addition, the waveform of the exclusive OR H of the currently processed data G and the previously processed data D (G waveform of one cycle before) is at H level only in one cycle from time t1 and time t3 when the level of the current data G changes. Become. Therefore, this exclusive OR H
The waveform shows that the normal contact state signal, excluding chattering and noise, has changed from its state before jX. Further, the operation signal data J waveform represented by the AND waveform of the exclusive OR H waveform and the currently processed data waveform G is at the H level for one rising period of the currently processed data G waveform.

Therefore, pressing the key of this contact 10 becomes a key operation start signal.

With the input device configured in this way, as shown in FIG. 6, the current processed data G waveform indicating a normal contact state signal does not reach the H level in the chattering variation region R1 immediately before the key is operated manually. If the key is held down, the R2 area of the state is 2.
When the cycle continues, it becomes H level in the second cycle. , and the waveform of the operation signal J indicating the start of the press-down key operation is the waveform of the R
When the two regions continue for two periods, only the second period becomes H level. Therefore, by using this operation signal J as a key operation signal, the adverse effects of chattering and noise can be removed.

In addition, a key signal (
As shown in Fig. 5, the processing to remove chattering and noise from the switch signal) is performed in the interrupt processing routine for CP (Jl), so other processing does not go into a waiting state. When the processing is completed, the currently processed data G obtained from the currently processed data C is stored in each data memory RA1, RA2 as the previous data KS and previously processed data D, respectively, and is read out when calculating the processed data in the next cycle. Therefore, each time the current data C is read, the previously processed data D is used.
There is no need to calculate. Therefore, data processing speed can be improved.

Further, the period TrJ of the interrupt signal TM is approximately the same as the chattering period (for example, 1 to 21R8) as shown in FIG.
), the delay time can be significantly reduced compared to conventional methods. Therefore, the overall processing time can be further reduced.

Further, when the input device of the present invention is applied to an electronic typewriter, a change in the key operation signal J is detected only when the contact 1o shifts from the OFF state to the ON state, so that it is suitable for ordinary character keys. Furthermore, in the case of a key that repeats line feed (paper feed) when held down, such as a carriage return key, by using the current processing data G in Figure 6 as a key human input signal, the key operation can be performed normally as described above. Since the timing of reading as a key operation is early, it can be determined quickly whether this key press operation is a key operation for continuous paper feed or a paper feed operation for only one line, and the paper feed operation is not affected.

Note that the present invention is not limited to the embodiments described above. In the embodiment, a keyboard on which a plurality of keys are arranged is used as a switch mechanism, but an ordinary push button switch or the like may be used.

[Effects of the Invention] As described above, according to the present invention, data processing for removing chattering and noise is performed within a certain cycle in synchronization with an interrupt signal at fixed cycle intervals. Therefore, the time from the switch input operation to the output of the normal switch operation signal can be shortened, and the processing efficiency of the entire system including the control section connected to this input device can be improved.

[Brief explanation of drawings]

The figures show an input device according to an embodiment of the present invention, FIG. 1 is a block diagram showing the overall configuration, and FIG. 2(a)
is a layout diagram of each contact point of the keyboard, FIG. 3 (b) is a wiring diagram of each contact point, FIG. 3 is a diagram showing the main memory of the storage section, FIG. is a flowchart showing the operation, and FIG. 6 is a time chart showing the operation. 1... CPLJ, 2... Pass line, 3... Keyboard (switch mechanism), 4... Decoder, 5...
I10 port, 6...ROM, 7...RAM, 8...
...I10 interface, 9...Clock oscillator (timer circuit).

Claims (1)

[Claims] A switch mechanism that outputs a switch state signal corresponding to a switch operation state, a timer circuit that outputs an interrupt signal at fixed periodic intervals, and a switch that is output from the switch mechanism in synchronization with the interrupt signal from the timer circuit. a data reading means for reading the status signal as data; a previously read data memory for storing the previous data read in the previous cycle of the interrupt signal by the data reading means; and a data processing for the previous data. a previous processing data memory for storing the previous processing data obtained by the data reading means; a logical product means, a logical sum means for calculating the logical sum of the current data and the previous data, and a logical sum value of the logical product value obtained by the first logical product means and the previous data; data processing means for calculating the logical product of the logical sum value and the logical sum value obtained by the logical sum means as a currently processed data value; and the currently processed data calculated by this data processing means and the previously processed data. an exclusive OR means for calculating an exclusive OR with the previously processed data stored in the data memory; and an exclusive OR value obtained by the exclusive OR means and an exclusive OR value obtained by the data processing means. It is characterized by comprising a second logical product means for calculating a logical product with the currently processed data, and an output means for outputting the logical product value obtained by the second logical product means as a switch operation signal. Input device.