JP3049109B2 - Input detection method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an input detection method, and more particularly to an input detection method for a binary signal having a value of 0 or 1.

[0002]

2. Description of the Related Art For example, when controlling a predetermined control target using a microcomputer based on a certain sensor output,
In many cases, the sensor output is input to a microcomputer in the form of a binary signal that takes a value of 0 or 1, and the microcomputer outputs the state of the input binary signal at the time of startup or the input binary signal after startup. A predetermined command is often output to a control target in accordance with a rising change or a falling change of.

For example, in the in-vehicle TV receiving system shown in FIG. 5, the microcomputer 3 controls the image control circuit 4 based on the output of the side brake switch 1, and determines whether the side brake (not shown) is released or applied. When the video output is turned on / off, the side brake (not shown) is applied, and the side brake switch 1 is turned on.
Is closed and the logic 0 is output when 0 V is output. Conversely, the binary signal that becomes logic 1 when the side brake is released and the side brake switch 1 is opened and + B is output is expressed by I.
/ F (interface) circuit 2 inputs to microcomputer 3.

When the system is started, the microcomputer 3 performs a predetermined input detection operation. If the binary signal input from the I / F circuit 2 is 0, the microcomputer 3 outputs a video ON command to the video control circuit 4, and the TV 3 The video signal output from the tuner 5 is output to the CRT display 6 to display the video on the screen. If the binary signal is 1, the video off command is output to the video control circuit 4 and the video output to the CRT display 6 is performed. To stop the image from appearing on the screen.
However, the audio signal output from the TV tuner 5 is output to the speaker 7 and output as audio regardless of the value of the binary signal.

After the system is started, the microcomputer 3 performs a predetermined input detection operation. When the binary signal input from the I / F circuit 2 falls from 1 to 0, the microcomputer 3 issues a video ON command to the video control circuit 4. To output the image on the screen, and conversely, if the binary signal rises from 0 to 1,
An image off command is output to the image control circuit 4 to erase the image on the screen.

FIG. 6 is a flowchart showing main control processing of the microcomputer 3, and FIG.
FIG. 8 is a flowchart for explaining the operation of the microcomputer 3. When the system is started, the microcomputer 3 performs a predetermined initial setting process, and sets the three bits (b ₂₎ provided in the memory. , B ₁ , b ₀ ) are all set to 0, a predetermined start flag SF is set to 1 and the fall detection flag LF and the rise detection flag HF are set to 0 (step in FIG. 6). 101). Next, a timer for measuring a fixed time is started, and when the time is up (steps 102 and 103), a predetermined input detection process is performed (step 104, see FIG. 7).

In the input detection processing, first, a start flag SF
Is determined (step 201 in FIG. 7),
So YES, the check value by entering the binary signal from the I / F circuit 2 (see t ₀ in step 202, FIG. 8 (1)). For example, when the side brake is applied in advance and the binary signal is 0, the fall detection flag LF is set to 1 (step 20).
3), the start flag SF is lowered to 0 (step 2)
04).

Next, the microcomputer 3 proceeds to step 105 in FIG. 6 and determines whether or not the falling detection flag LF is set. If YES, the microcomputer 3 outputs a video ON command to the video control circuit 4 (step 10).
6) The fall detection flag LF is dropped to 0 (step 107). The video control circuit 4 which has received the video ON command converts the video signal input from the TV tuner 5 into a C signal.
The image is output to the RT display 6, and the image is projected on the screen. Thus, when the system is started while the vehicle is stopped with the side brake applied, the driver can view the video and audio of the TV broadcast.

When the side brake is released in advance, the binary signal output from the I / F circuit 2 is 1, so that the microcomputer 3 executes step 205 instead of step 203 in FIG. The rising detection flag HF is set to 1 and the starting flag SF is decreased to 0
(Step 204). Therefore, step 1 in FIG.
In step 05, the determination is NO, and in step 108, the determination is YES. A video off command is output to the video control circuit 4 (step 109), and the rising detection flag HF is lowered to 0 (step 110). The video control circuit 4 to which the video off command is input does not output the video signal input from the TV tuner 5 to the CRT display 6, but makes the screen disappear. Thus, when the system is activated during traveling, the driver can only listen to the sound of the TV broadcast.

Here, it is assumed that the TV image is turned on at the time of system startup, and after the processing of step 107,
The microcomputer 3 returns to step 102 to start the timer again, and when the time is up, proceeds to the flow of FIG. 7 and checks whether the start flag SF is set (step 201). Now since NO, check the value by entering the binary signal from the I / F circuit 2 (see t ₁ in step 206, FIG. 8 (1)). If remains 0 b ₀ of the data buffer is zero (step 207). Then, it is determined whether b ₁ of the data buffer matches the b ₀ (step 208), since YES, followed by, b ₂ is b
_It is determined whether the _value matches ₀ (step 209).
So ES, the b ₀ transfers the b ₁ to b ₂ b ₁
Is not processed (because the result is the same),
It returns to the flow of FIG. However, since both the steps 105 and 108 are NO, the microcomputer 3 returns to the step 102 and restarts the timer. Hereinafter, similarly, if the binary signal does not change from 0,
The microcomputer 3 does not perform control output.

Thereafter, when the driver releases the side brake to start the vehicle, the I / F circuit 2 sets the binary signal to 1. At this time, the microcomputer 3 determines that the binary signal is 1 in step 206 of FIG. 7 (see t _{i in} FIG. 8A), and sets b ₀ to 1 (step 210).
Since b ₁ and b ₀ is the mismatch, transfers the b ₀ to b ₁ to the b ₁ and 1 (step 208 and 211). On this occasion,
It does not perform processing for transferring the previous b ₁ to b ₂ (for eventually the same). Then, returning to the flow of FIG. 6, since both of steps 105 and 108 are NO, after a predetermined time, it is again checked whether the start flag SF is set (step 201 of FIG. 7). The binary signal is checked (see t _{i + 1 in} FIG. 8A). At this time, if the binary signal is 1, b ₀
Is set to 1 (step 210).

At this time, b ₀ in the data buffer is the value of the binary signal input this time, b ₁ is the value of the binary signal input last time, and b ₂ is the value of the binary signal input last time.
Then, it is determined whether the microcomputer 3 b ₀ coincides with b ₁ (step 208), since the errors due to chattering If a match does not occur, b ₀ (or b ₁₎
And b ₂ are either judged matches (step 209). Here, since they do not match, the microcomputer 3 transfers b ₁ (or b ₀ ) to b ₂ and sets b ₂ to 1 (step 212). At this time, the process of transferring b ₀ to b ₁ is not performed (because the result is the same). Since b ₀ is 1, it is determined that the binary signal has risen, and the rising detection flag HF is set to 1 (steps 213 and 21).
4).

Next, the microcomputer 3 returns to the flow of FIG. 6, determines YES in step 108, outputs a video off command to the video control circuit 4 (step 110), and sets the rising detection flag HF to 0 to reset it to 0. (Step 110). The video control circuit 4 to which the video off command has been input does not output the video signal input from the TV tuner 5 to the CRT display 6, but makes the screen disappear. As a result, during driving, the driver
You can only listen to the V broadcast audio.

After step 110, the microcomputer 3 checks after a certain time whether the start flag SF is set (step 201 in FIG. 7). Since the answer is NO, the microcomputer 3 checks the binary signal in step 206 (FIG. 8).
(See t _{i + 2 in} (1)). If also the binary signal at this time is H, the b ₀ to 1 (step 000). At this time, b ₀ of the data buffer is the value of the binary signal input this time, b ₁
The value of the binary signal the previously input, b ₂ has a value of binary signals before the last input. However, since b ₀ = b ₁ = b ₂ , the process of transferring b ₁ to b ₂ and transferring b ₀ to b ₁ is not performed, and the process returns to the flow of FIG. 6 (step 20).
8, 209). Hereinafter, similarly, if the binary signal remains at 1 and does not change, the microcomputer 3 does not output the control.

Thereafter, when the driver stops the vehicle and applies the side brake, the I / F circuit 2 sets the binary signal to 0. At this time, the microcomputer 3 determines that the binary signal is 0 in step 206 in FIG. 7 (see t _{j in} FIG. 8B), sets b ₀ to 0 (step 207), and then sets b ₁ and b _0. since but a mismatch, the b ₁ transfers the b ₀ to b ₁ and 0 (step 211). Then, returning to the flow of FIG. 6, since both of steps 105 and 108 are NO, after a predetermined time, it is checked whether or not the start flag SF is set (step 201 of FIG. 7). Check the signal ((Fig. 8
(See t _{j + 1 in} (2)). At this time, if the binary signal is 0, b _{0 is set} to 0 (step 207). At this time, b ₀ of the data buffer is the value of the binary signal input this time, b ₁
The value of the binary signal the previously input, b ₂ has a value of binary signals before the last input. Subsequently, the microcomputer 3 determines whether b ₀ coincides with b ₁ (step 20
8) If they match, no error due to chattering has occurred, so it is determined whether or not b ₀ (or b ₁ ) and b ₂ match (step 209). Here, since discrepancies, the microcomputer 3 is the b ₂ and 0 to transfer the b ₁ to b ₂ (step 212). And if b ₀ is 0,
It is determined that the binary signal has fallen, and the fall detection flag LF is set to 1 (steps 213 and 215).

Next, the microcomputer 3 returns to the flow of FIG. 6 and returns YES to the step 105. Therefore, the microcomputer 3 outputs a video ON command to the video control circuit 4 (step 106) and drops the fall detection flag LF to 0. (Step 107). The video control circuit 4 which has received the video ON command outputs the video signal input from the TV tuner 5 to the CRT display 6 and causes the video to be displayed on the screen. Thereby, the driver can enjoy the TV video together with the TV sound again.

[0017]

Here, only when the system is started, the microcomputer 3 operates at step 20 in FIG.
The second and subsequent processes are performed to output the video on command or the video off command for the following reason.
That is, initially, the binary signal is in a constant state of either H or L, and the processing after step 206 is processing for detecting the rise or fall of the binary signal. Is not possible.

However, since the special processing is performed at the time of starting the system, when the rising or falling of the binary signal is detected after the system is started, the start flag SF is always set at step 201 in FIG. It is necessary to execute a process of determining whether the user is standing, and the processing speed becomes slow, and there is a problem that it takes time from the change of the binary signal to the detection of the change.

As described above, the present invention improves the processing speed,
An object of the present invention is to provide an input detection method capable of quickly detecting a change when a binary signal changes.

[0020]

SUMMARY OF THE INVENTION According to the present invention, a binary signal is checked before starting a rising / falling detection operation, and when the binary signal is 1, an initial value is set.
The data indicating at least the previous input value of the data buffer is set to 0, and when the binary signal is 0, the data indicating at least the previous input value of the data buffer is set to 1 as an initial value. Means, a means for inputting a binary signal at fixed time intervals, and holding the current, previous, and previous input values in the data buffer; and checking each input value held in the data buffer to check the current and previous values. When the input values are both 0 and the previous and previous input values are 1, a predetermined process is performed assuming that a fall has occurred, and the present and previous input values are both 1 and
When the previous input value is 0, it is determined that a rise has occurred, and this is achieved by means for performing a predetermined process.

[0021]

According to the present invention, before starting the rising / falling detecting operation, the binary signal is checked, and when the binary signal is 1, at least the previous input value of the data buffer is set as an initial value. Is set to 0, and when the binary signal is 0, the data indicating at least the previous and previous input values of the data buffer is set to 1 as an initial value , and the binary signal is input at regular intervals, and , The previous and previous input values are stored in the data buffer, and each input value stored in the data buffer is checked.
When the previous and previous input values are 1, a predetermined process is performed on the assumption that a fall has occurred, and when the current and previous input values are both 1 and the previous and previous input values are 0, a rise has occurred. Perform predetermined processing. This allows chattering
Malfunction can be prevented.
No special processing is required at the start of output operation, and the binary signal changes.
The rise and fall can be detected quickly when the data is converted.
Only if the binary signal is 1 immediately after the system is started up.
Is assumed to have occurred (rising detection).
If the signal is 0, it is considered that a falling has occurred (
And a predetermined operation can be performed.

[0022]

FIG. 1 is an overall configuration diagram of an in-vehicle TV receiving system according to an embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a side brake switch, which closes the switch to output 0 V when the brake is applied in conjunction with the side brake, and opens the switch to output + B when the brake is released. 2 is I /
This is an F circuit. A signal is input from the side brake switch 1. When the input signal is 0V, logic 0 (predetermined L level when positive logic, predetermined H level when non-logic), and logic 1 (positive when + B). It outputs a binary signal that is at a predetermined H level when it is logic, and at a predetermined L level when it is not logic. A microcomputer 3A receives a binary signal from the I / F circuit 2 and performs on / off control of a TV image. Reference numeral 4 denotes a video control circuit that outputs or stops outputting a TV video signal under the control of the microcomputer 3A. 5 is T
The V tuner demodulates a TV audio signal and a TV video signal from a signal received by the antenna 8, amplifies and demodulates the signal, and outputs the amplified signal to the outside. Reference numeral 6 denotes a CRT display which, when a TV video signal is input from the TV tuner 5 via the video control circuit 4, displays a TV video on a screen. Reference numeral 7 denotes a speaker that receives a TV audio signal from the TV tuner 5 and reproduces the sound.

In the memory of the microcomputer 3A,
A 3-bit data buffer area (b ₂ , b ₁ , b ₀ ) is provided. Among them, b ₀ indicates the data of the current input value of the binary signal, b ₁ indicates the data of the previous input value of the binary signal, and b ₂ indicates the data of the previous input value of the binary signal. Show.

FIG. 2 is a flowchart showing a main control process of the microcomputer 3A, FIG. 3 is a flowchart showing an input detection process of the microcomputer 3A, and FIG. 4 is a diagram explaining an input detection operation of the microcomputer 3A. Hereinafter, description will be made with reference to these figures.

When the system is started, the microcomputer 3A performs a predetermined initial setting process, sets the fall detection flag LF and the rise detection flag HF to 0, and sets both to 0.
In addition, a binary signal is input from the I / F circuit 2 and the value is checked. If the binary signal is 0 (in a state where the side brake is applied), 3 bits (b
₂ , b ₁ , b ₀ ), all the data buffers are set to 1. If the binary signal is 1 (in a state where the side brake is released), all the data buffers are set to 0 (see FIG. 2). Step 301). As a result, the data buffer
The state of the side brake is in the opposite state to the actual state in advance,
In this state, the state is equivalent to detecting the value of the binary signal three times. Here, the binary signal is 0 and b ₂
= B ₁ = b ₀ = 1.

Next, the microcomputer 3A starts a timer for measuring a predetermined time, and when the time is up (steps 302 and 303), performs a predetermined input detection process (step 304, see FIG. 3). In the input detection process, first, a binary signal is input from the I / F circuit 2 and the value is checked (step 401 in FIG. 3, t in FIG. 4 (1)).
₀ ). After the binary signal is set to 0, so b ₀ 0 (step 402), since b ₁ and b ₀ is a mismatch, b ₀
The transferred to b ₁ to b ₁ to 1 (step 403,4
04). In this case, it does not perform the process of transferring the previous b ₁ to b ₂ (for eventually the same). Then, returning to the flow of FIG. 2, it is determined whether the falling flag LF is set or the rising flag HF is set (steps 305 and 306). Here, since both are NO, the process returns to step 302 to restart the timer.

[0028] When the time is up, the microcomputer 3A again checks the binary signal in step 401 of FIG. 3 (see t ₁ in FIG. 4 (1)). At this time, if the binary signal is 0, b _{0 is set} to 0 (step 402). At this time, the value of b ₀ is a binary signal input current data buffer, b ₁ is the value of the binary signal the previously entered. b
₂ (= 1) is regarded as the value of the previously input binary signal.
The microcomputer 3A determines whether b ₀ coincides with b ₁ (step 403), since the errors due to chattering If a match does not occur, then judges whether or b ₀ (or b ₁₎ and b ₂ are identical (Step 40
5). Here, since there is a mismatch, the microcomputer 3
A transfers b ₁ (or b ₀ ) to b ₂ and sets b ₂ to 1 (step 406). At this time, the process of transferring b ₀ to b ₁ is not performed (because the result is the same). And
Since b ₀ is 0, it is determined that a fall of the binary signal has occurred, and the fall detection flag LF is set to 1 (steps 407 and 408).

Next, the microcomputer 3A is shown in FIG.
Returning to the flow of FIG.
An image ON command is output to the image control circuit 4 (step 307), and the fall detection flag LF is dropped to 0 (step 308). The video control circuit 4 to which the video ON command has been input outputs the TV video signal input from the TV tuner 5 to the CRT display 6, and causes the screen to display the TV video. Thus, when the system is started while the vehicle is stopped with the side brake applied, the driver can view the video and audio of the TV broadcast.

When the side brake is released in advance (b ₂ = b ₁ = b ₀ = 0 in the initial setting process), the binary signal output from the I / F circuit 2 becomes 1 since going on, the microcomputer 3A is a binary signal in step 401 of FIG. 3 is to the b ₀ and 1 it is determined that the 1 (step 409), the rising edge detection flag HF in the second input detection processing 1 (step 41)
0). Then, when returning to the flow of FIG.
6 is determined to be YES, an image off command is output to the image control circuit 4 (step 309), and the rising detection flag HF is dropped to 0 (step 31).
0). The video control circuit 4 that has received the video off command receives the T
The video signal input from the V tuner 5 is not output to the CRT display 6 and the screen is turned off. Thus, when the system is activated during traveling, the driver can only listen to the sound of the TV broadcast.

Here, assuming that the TV image is turned on at the time of system startup, after the processing of step 308,
The microcomputer 3A returns to step 302 to start the timer again, and when the time is up, proceeds to the flow of FIG. 3 and inputs a binary signal from the I / F circuit 2 to check the value (step 401, FIG. reference t ₂ of 1)). If the binary signal remains 0, b
_{0 is set} to 0 (step 402). Then, it is determined whether b ₁ of the data buffer matches the b ₀ (Step 40
3), since YES, subsequently, it is determined whether b ₂ coincides with b ₀ (step 405), since YES here, b
_The process of transferring ₁ to b ₂ and transferring b ₀ to b ₁ is not performed (because the result is the same), and the process returns to the flow of FIG. However, since both steps 305 and 306 are NO, the microcomputer 3A
Returning to step 2, the timer is restarted. Hereinafter, similarly, if the binary signal remains at 0 and does not change, the microcomputer 3A does not output the control.

Thereafter, when the driver releases the side brake to start the vehicle, the I / F circuit 2 sets the binary signal to 1. At this time, the microcomputer 3A
In step 401, it is determined that the binary signal is 1 (FIG. 8 (1)).
T _i see) of, after you and the b ₀ 1 (step 40
9), b ₁ and b ₀ because a mismatch, transfers the b ₀ to b ₁ to the b ₁ and 1 (step 403 and 404). Then, returning to the flow of FIG. 2, since both steps 305 and 306 are NO, after a certain time, the binary signal is checked again (step 401 in FIG. 3, FIG. 4 (1)).
T _{i +1} ). At this time, if the binary signal is 1, b
_{0 is set} to 1 (step 409).

At this time, b ₀ in the data buffer is the value of the binary signal input this time, b ₁ is the value of the binary signal input last time, and b ₂ is the value of the binary signal input previously.
Then, the microcomputer 3A is b ₀ is determined whether to match the b ₁ (step 403), or because an error due to chattering If a match does not occur, then b ₀ (or b ₁₎ and b ₂ are identical Judge (Step 40)
5). Here, since there is a mismatch, the microcomputer 3
A transfers b ₁ (or b ₀ ) to b ₂ and sets b ₂ to 1 (step 406). Then, since b ₀ is 1, it is determined that the rising of the binary signal has occurred, and the rising detection flag HF is set to 1 (steps 407 and 410).

Next, the microcomputer 3A is shown in FIG.
Returning to the flow of, it is determined YES at step 306,
A video off command is output to the video control circuit 4 (step 309), and the rising edge detection flag HF is dropped to 0 (step 310). The video control circuit 4 to which the video off command has been input does not output the TV video signal input from the TV tuner 5 to the CRT display 6, but makes the screen disappear. This allows the driver to listen only to the sound of the TV broadcast during traveling.

After step 310, the microcomputer 3A checks the binary signal at step 401 in FIG. 3 after a certain period of time (see t _{i + 2 in} FIG. 4 (1)). If also the binary signal at this time is 1, the b ₀ to 1 (step 409). At this time, b ₀ of the data buffer is the value of the binary signal input this time, b ₁ is the value of the binary signal input last time,
b ₂ is the value of the previously input binary signal. However, since b ₀ = b ₁ = b ₂ , the flow returns to the flow of FIG. 2 (steps 403 and 405). Hereinafter, similarly, if the binary signal does not change and remains at 1, the microcomputer 3A
Does not output control.

Thereafter, when the driver stops the vehicle and applies the side brake, the I / F circuit 2 sets the binary signal to 0. At this time, the microcomputer 3A determines that the binary signal is 0 in step 401 in FIG. 3 (t _{j in} FIG. 4 (2)).
After setting b ₀ to 0 (step 402), b ₁
Since b ₀ is a mismatch and, b ₁ to transfer the b ₀ to b ₁
Is set to 0 (steps 403 and 404). And FIG.
Since both steps 305 and 306 are NO, the binary signal is checked again after a certain period of time (see step 401 in FIG. 3 and t _{j + 1} in FIG. 4 (2)). At this time, if the binary signal is 0, b _{0 is set} to 0 (step 402). At this time, b of the data buffer
₀ the value of the binary signal input time, b ₁ is the value of the binary signal the previously input, b ₂ has a value of binary signals before the last input. Subsequently, the microcomputer 3A sets b ₀ to b
_It is determined whether or not ₁ matches (step 403). If there is no error due to chattering, it is determined whether or not b ₀ (or b ₁ ) and b ₂ match (step 40).
5). Here, since discrepancies, the microcomputer 3A is a b ₂ a 0 by transferring b ₁ to b ₂ (step 406). If b ₀ is 0, it is determined that a fall of the binary signal has occurred, and the fall detection flag LF is set to 1 (steps 407 and 408).

Next, the microcomputer 3A is shown in FIG.
Returning to the flow of YES, since YES is obtained in step 305,
An image ON command is output to the image control circuit 4 (step 307), and the fall detection flag LF is dropped to 0 (step 308). The video control circuit 4 that has received the video on command outputs the TV video signal input from the TV tuner 5 to the CRT display 6 and causes the video to be displayed on the screen. Thereby, the driver can enjoy the TV video together with the TV sound again.

According to this embodiment, the input detection operation after the system is started can be executed with the minimum necessary processing, so that the processing speed is improved, and when the binary signal changes, the change is quickly detected and the predetermined signal is detected. TV video on / off control can be performed.

In the above embodiment, at the time of initial setting (see step 301 in FIG. 2), if the binary signal is 0, b ₂ = b ₁ = b ₀ = 1, but b ₂ = b ₁ = 1 and b
₀ may be arbitrary, or b ₂ = 1 and b ₁ and b ₀ may be arbitrary. Similarly, if the binary signal is 1, b ₂ = b ₁ =
Although b ₀ = 0, b ₂ = b ₁ = 0 and b ₀ may be arbitrary, or b ₂ = 0 and b ₁ and b ₀ may be arbitrary.

[0040]

As described above, according to the present invention, the rise and fall
Before starting the detection operation, the binary signal is checked.
When the binary signal is 1, the initial value is
At least the data indicating the previous and previous input values is set to 0, and the binary
When the signal is 0, the number of data buffers
In both cases, the data indicating the previous and previous input values is set to 1, a binary signal is input at regular intervals, and the current, previous, and previous input values are stored in the data buffer, and each input value stored in the data buffer is stored. Is checked, if the current and previous input values are both 0 and the previous and previous input value is 1, a predetermined process is performed assuming that a fall has occurred, and the current and previous input values are both 1 and the previous When the previous input value is 0, a predetermined process is performed on the assumption that a rise has occurred. As a result,
Malfunction due to tapping can be prevented, and
No special processing is required at the start of the fall detection operation.
Quick detection of rising and falling when signal changes
it can. Only when the system is started, the binary signal is 1.
If a rise has occurred, it is assumed that a rise has occurred (rise detection).
If the binary signal is 0, it is considered that a falling has occurred.
Predetermined operation can be performed without detecting (falling edge)
You.

[Brief description of the drawings]

FIG. 1 shows an in-vehicle TV embodying the input detection method according to the present invention.
FIG. 1 is an overall configuration diagram of a receiving system.

FIG. 2 is a flowchart showing main control processing by the microcomputer of FIG. 1;

FIG. 3 is a flowchart showing an input detection process by the microcomputer of FIG. 1;

FIG. 4 is a diagram illustrating an input detection operation of the microcomputer of FIG. 1;

FIG. 5 is an overall configuration diagram of a conventional in-vehicle TV reception system.

FIG. 6 is a flowchart showing main control processing by the microcomputer of FIG. 5;

FIG. 7 is a flowchart showing input detection processing by the microcomputer of FIG. 5;

FIG. 8 is a diagram illustrating an input detection operation of the microcomputer of FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Side brake switch 2 I / F circuit 3A microcomputer 4 Video control circuit

Claims (1)

(57) [Claims] 1. A binary signal having a value of 0 or 1 is input at regular intervals, and the current, previous, and previous input values are stored in a data buffer, and each input value stored in the data buffer is checked. Then, both the current and previous input values are 0,
When the input value of the previous and previous times is 1, a predetermined process is performed on the assumption that a fall has occurred, and both the current and previous input values are 1,
In the input detection method in which a predetermined process is performed when the previous input value is 0 when a rise has occurred, a binary signal is checked before starting a rise / fall detection operation. data indicative of at least before the last input value of the de <br/> Tabaffa as an initial value when the value signal is 1 and 0, at least before the last input data buffer as the binary signal is the initial value when the 0 Data indicating the value is 1
An input detection method characterized by the following.