JPS6243211B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a key input device having an oscillation circuit with an oscillation stop function.

Here, a key input device for a remote control transmitter will be explained.

The circuit configuration of the remote control transmitter is
Generally, as shown in FIG. 1, it includes an oscillation circuit 1 with an oscillation stop function that generates a reference signal, a timing generation circuit 2, a scan output circuit 4 that constitutes a keyboard matrix 3, a key input circuit 5, and this key input circuit. an encoder circuit 6 that processes the scan signal input to the key input circuit 5; a determination circuit 7 that determines whether the scan signal is input to the key input circuit 5; a decoder circuit 8 that converts into a transmission signal corresponding to the
an output circuit 9 that receives a signal from and outputs a transmission signal;
It is composed of.

The operation of the key input circuit 5 in the circuit configured as described above will be explained with reference to the time chart shown in FIG.

FIG. 2 shows the input signal applied to the input terminal 10 of the key input circuit 5 and the output terminal 4 of the scan output circuit 4.
0 scan signal with keyboard matrix 3,
This is a time chart for when the key is turned on and off.

In the figure, A is the input terminal 1 of the key input circuit 5.
0, and B, C, and D indicate the output terminals 40 and 5 of the scan output circuit 4, respectively.
0 and 60, that is, a scan output signal, E is a key input judgment detection signal that determines the presence or absence of a key input, and F is a key input that causes or stops the oscillation circuit 1 depending on the presence or absence of a key input. This shows a judgment signal.

First, in the key input standby state (period a) in which no key in keyboard matrix 3 is turned on,
The state of the input terminal 10 of the key input circuit 5 is "H", and the output terminals 40, 5 of the scan output circuit 4
The states B, C, and D of 0, 60 are "L", the key input judgment detection signal H is "L", the key input judgment signal H is "L", and the oscillation circuit 1 has stopped oscillating. .

Then, point A is when the keys of the keyboard matrix 3 are turned on, and at this time, the key input circuit 5
The input terminal 10 of the scan output circuit 4 detects "L" of the output terminal 40, the key input judgment signal changes from "L" to "H", the oscillation circuit 1 starts oscillating, and the timing generation circuit 2 The scan output circuit 4 outputs a scan signal. here,
The initial period when the scan signal is output is as follows, and if the key is kept on, the scan signal will be output at the period of . Then, the key input determination detection signal H operates at a cycle similar to the cycle of the scan signal. Here, this key input determination detection signal E is a signal for determining whether or not a scan signal is input to the key input circuit 5 within one cycle of the scan signal.

Next, the period of b is the keyboard matrix 3
This is the period during which the key is turned on. Then, when the key is turned off at point B, the scan signal is input to the input terminal 10 of the key input circuit 5 in the period of the scan signal, so the key input judgment detection signal H in the period is the same as when the key is turned on. It is determined that the key input determination signal is "H".

Then, in the cycle, the key input determination detection signal H determines that the key input is turned off, so the key input determination signal H becomes "L" and the oscillation of the oscillation circuit 1 stops.

As a result of the above operations, when a key of the keyboard matrix 3 is turned on, the oscillation circuit 1 is activated, and when the key is turned off, the oscillation circuit 1 and oscillation are stopped.

However, generally keyboard matrix 3
In this case, the input wiring of the key input circuit 5 and the output wiring of the scan output circuit 4 intersect, and the key input is easily affected by capacitive coupling between the wirings.

For example, as shown in the time chart of FIG. 3, at the end of the scan cycle when no scan signal is input to the key input circuit 5, the scan output signals B, C, and D all change from "H" to "L".
However, due to the capacitive coupling between the wires of the keyboard matrix 3, the scan output signals B, C,
"L" in D is the input terminals 10 and 2 of the key input circuit 5.
It may be added to 0.30.

Therefore, at the end of the scan period C, the key input determination signal becomes "L" once, but
Due to the above-mentioned reason, the signal becomes "H" again, and the oscillation circuit 1 continues to oscillate, and the current consumption is greater than when the oscillation is stopped, resulting in unnecessary battery consumption.

In order to eliminate such a drawback, it is possible to connect a capacitor between each input terminal 10, 20, 30 of the key input circuit 5 and GND to divide the capacitance between the wirings of the keyboard matrix 3. , the number of parts increases, which is a disadvantage in transmitters that are becoming more compact.

In view of the above points, the present invention has been made to solve such problems, and its purpose is to eliminate the drawbacks of the above-mentioned conventional circuits and to provide a key input device that does not require connecting a capacitor to an input terminal. It is about providing.

In order to achieve such an objective, the present invention includes:
In a key input device, a period for prohibiting reading of a key input circuit is set when a key is turned from on to off.Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 4 is a block diagram showing an embodiment of a key input device according to the present invention, and shows an example in which the present invention is applied to a remote control transmitter.

In FIG. 4, the same reference numerals as those in FIG. This is a timer circuit that starts operating when it is determined that the scan signal is not being input from the key input circuit 5.

When the selection of the keyboard matrix 3 is completed, the timer circuit 10 sets an input reading prohibition period for the key input circuit 5, and the oscillation circuit 1 is configured to stop oscillating after the input reading prohibition period ends. .

Next, the operation of the embodiment shown in FIG. 4 will be explained using the time chart shown in FIG. In FIG. 5, the same reference numerals as in FIGS. 2 and 3 indicate corresponding parts, and ``g'' indicates the operating state of the timer circuit 10.

First, at point A, when the key of the keyboard matrix 3 is turned on, the key input judgment signal changes from "L" to "H", the oscillation circuit 1 starts oscillating, and the reference signal is output from this oscillation circuit 1. The timing generating circuit 2 that receives the signal operates, and the scan output circuit 4 that receives the signal from the timing generating circuit 2 outputs the scan signals shown in (b), (c), and (d). A scan signal is input to the key input circuit 5 during the scan period, but no scan signal is input to the key input circuit 5 during the scan period.
At this time, at the rise of the key input determination detection signal E, the timer circuit 10 for inhibiting key input reading is activated. The operating state of this timer circuit 10 is shown in FIG. Here, the period during which the timer circuit 10 is working as a timer function, that is, the period during which key input reading is inhibited, is the period when the signal G is "H".

Then, reading of the key input circuit 5 is prohibited during this key input reading prohibition period, that is, the "H" period shown in G. In between, it is sufficient to provide a switch means or the like which is turned off by the "H" signal shown in (g) above.In short, the output from the keyboard matrix 3 is switched to the key input circuit 5 by the "H" signal in the timer circuit 10. It is best to prevent it from being transmitted to On the other hand, the key input determination signal H which is the output signal of the determination circuit 7 becomes "L" due to the fall of the key input determination detection signal H, but the "H" period when the timer circuit 10 is operating is The oscillation circuit 1 continues to oscillate, and when the signal G indicating the operating state of the timer circuit 10 becomes "L", the oscillation is stopped and the circuit enters a standby state. In other words, when either the key input judgment signal or G indicating the operating state of the timer circuit 10 is "H", the oscillation circuit 1 is oscillating, and when both are "L", the oscillation circuit 1 is oscillating. That is why it is stopped.

Then, set the key input reading prohibition period as mentioned above.
Due to capacitive coupling, if the time period during which the scan signals B, C, and D are applied to the input of the key input circuit 5 is made sufficiently long, the drawback that the oscillation of the oscillation circuit 1 does not stop when the key is turned off in the conventional circuit can be solved. Can be removed.

Note that in the above embodiment, the timer circuit 10
Although one block is provided as the above, the same effect can be obtained even if the timing generation circuit 2 is provided with an equivalent timer function.

Further, although the present invention has been described above using an example in which the present invention is applied to a transmitter for remote control, the present invention is not limited to this, and the present invention is not limited to this, and the oscillation occurs when the keys of the keyboard matrix 3 are turned off. It can be used in a key input device that is characterized by stopping and starting oscillation when the key is turned on.

As is clear from the above description, according to the present invention, when the key is turned from on to off, a period for prohibiting the reading of the key input circuit is set. This eliminates the disadvantage that the oscillation circuit does not stop oscillating, thereby eliminating wasteful power consumption, and eliminating the need for complicated means of connecting a capacitor to the input terminal. , the configuration is simplified, and the device can be simplified along with the simplification of the configuration, so the practical effects are extremely large.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of the circuit configuration of a conventional remote control transmitter, FIGS. 2 and 3 are time charts for explaining the operation of FIG. 1, and FIG. 4 is a key input device according to the present invention. FIG. 5 is a block diagram showing one embodiment of the present invention, and FIG. 5 is a time chart for explaining the operation of the embodiment shown in FIG. 1...Oscillation circuit, 2...Timing generation circuit,
3... Keyboard matrix, 4... Scan output circuit, 5... Key input circuit, 7... Judgment circuit,
10...Timer circuit.

Claims (1)

[Claims] 1. An oscillation circuit with an oscillation stop function, a timing generation circuit that receives a reference signal from this oscillation circuit, a scan output circuit that inputs a signal from this timing generation circuit, and an output of this scan output circuit that outputs the output from this scan output circuit via a keyboard matrix. a key input circuit for input; a determination circuit for determining whether the output signal of the scan output circuit is input to the key input circuit through the keyboard matrix; and a determination circuit for determining whether the scan signal is input to the key input circuit. It operates for a period longer than the period affected by capacitive coupling between wires in the keyboard matrix from the time when it is determined that the input state has changed to the non-input state, and during that operation, reading of the key input circuit is prohibited, and after the operation is completed. A key input device comprising a timer for stopping oscillation of the oscillation circuit.