A car remote control system utilizing a signal in the form of electromagnetic wave or infrared ray called `keyless entry`. When receiving a predetermined wake-up signal, an MPU is once operated even when the received input signal is a noise signal to perform only judging operation of whether or not the input signal is normal. Only when judging that the input signal is a normal wake-up signal, the MPU controllably causes an electronic circuit to be shifted to a usual operation mode. When judging that the input signal is the noise signal prior to full input of the tuner signal, the MPU immediately shifts to a sleep mode. Thereby current consumption of an electronic control circuit can be suppressed.
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3. An electronic control apparatus for a car, comprising a tuner which receives a signal from a remote controller and transmits a signal to a microcomputer of an onboard controller, wherein an output terminal of said timer tuner is connected to an input terminal of said microcomputer, to a wake-us signal line of an output system and to an input terminal of a gate circuit, and an output terminal of said gate circuit is connected to a wake-up terminal of said microcomputer.
6. An electronic control method for a car having a tuner which receives a signal from a remote controller and outputs a predetermined signal to a microcomputer of an onboard controller, comprising the steps of
generating a wake-up signal; deciding whether the generated wake-up signal is supplied from a particular device; executing a function, when said generator wake-up signal is supplied from the tuner, for determining whether the generator wake-up signal is generated due to noise; and activating a predetermined device by the microcomputer when it is determined that the generated wake-up signal is not due to noise.
2. An electronic control apparatus for a car, comprising a tuner which receives a signal from a remote controller and outputs a predetermined signal to a microcomputer of an onboard controller,
means for the microcomputer to decide, when the microcomputer is woken up by generation of a wake-up signal, whether the generated wake-up signal is supplied from the tuner; means for the microcomputer to execute, when the generator wake-up signal is supplied from the tuner, a function for determining whether the generated wake-up signal is generated due to noise; and means for activating, when the generated wake-up signal is determined not to be due to noise, a predetermined device by the microcomputer.
5. An electronic control method for a car having a tuner receiving a signal from a remote controller and a microcomputer which activates one or more devices provided in the car when said tuner receives the signal from said remote controller, comprising the steps of
intermittently supplying electrical power to the tuner when a control system of the car is not activated; changing the power supply, when said microcomputer receives a wake-up signal, to the tuner into a normal supply state and activating a function for monitoring an output signal of the tuner, and outputting a wake-up request signal when the microcomputer decides that the received wake-up signal is the normal signal from the remote controller, for waking up a predetermined device.
7. An electronic control method for a car having a tuner which receives a signal from a remote controller, a microcomputer controlling and activating a device provided in the car, and a noise eliminating means for eliminating a high frequency noise contained in an output signal of said tuner, implemented by a software program executed via the microcomputer, comprising the steps of:
periodically sampling a signal inputted to the microcomputer from said tuner; checking the signal inputted to the microcomputer and again checking the signal inputted to the microcomputer after a set time shorter than the a periodic sampling period and longer than a period of the high frequency noise; and determining existence or absence of a the high-frequency noise on the basis of a state of signal obtained by the preceding steps.
1. An electronic control apparatus for a car having a tuner receiving a signal from a remote controller and a microcomputer which activates at least one device when said tuner receives the signal from said remote controller, comprising
means for intermittently supplying electric power to said tuner when a control system of the car is not activated; the microcomputer being provided with means for changing the power a supply of power to said tuner into a normal supply state and activating a function for monitoring an output signal of the tuner when the microcomputer receives a wake-up signal; and the microcomputer being provided with means for outputting a wake-up request signal for waking a predetermined device when the microcomputer has decided that the received wake-up signal is the a normal signal from the remote controller.
4. An electronic control apparatus for a car having a tuner which receives a signal from a remote controller, said and a microcomputer controlling and activating a device provided in the car, comprising:
means for eliminating a high frequency noise contained in an output signal of said tuner via a software program executed by the microcomputer, the microcomputer being configured to periodically sample a signal inputted to the microcomputer from the tuner; means for checking the signal inputted to the microcomputer and again checking the signal inputted to the microcomputer after a set time shorter than the a sampling period and longer than a period of the high frequency noise; and means for determining the existence or absence of a the noise on the basis of a state of signal obtained by the periodic sampling and by checking of the microcomputer.
9. An electronic control apparatus for a car, comprising a microcomputer configured to have low power consumption mode and to receive a plurality of signals including a signal from a remote controller at a wake-up terminal of said microcomputer,
a communications interface configured to receive a signal for waking-up at least one selected control; device from said microcomputer and to output a wake-up signal to the at least one selected control device, said microcomputer being further configured to perform function checking as to whether when a signal is inputted at said wake-up terminal of said microcomputer, the signal is from other than said remote controller, and when the signal inputted at said wake-up terminal was is the signal from one except other than said remote controller, said microcomputer being still further configured to output the signal for waking up a said selected control device at an output terminal of said microcomputer.
0. 13. An electronic control apparatus for a car, comprising:
a key insertion detecting unit for detecting the presence or absence of the key inserted into a key switch, a door state detecting unit for detecting an open or closed state of a door, a tuner connected to an antenna for receiving the signal from a remote control unit, and a control processing unit having; an input output interface connected with said tuner, said key insertion detecting unit, and said door state detecting unit, and a microprocessor for generating an output signal to be transmitted to another unit on the basis of a signal from said tuner, said key insertion detecting unit, and said door state detecting unit through said input output interface, said microprocessor being configured to be awakened for a short time period upon reception by the antenna of a signal to determine if the signal is or is not noise, and then wake-up another control unit for the first time when the signal is not noise.
0. 14. An electronic control apparatus for a car, comprising:
a tuner connected to an antenna for receiving the signal from a remote control unit, a trunk opening actuator electrically coupled to an actuator control unit for opening a trunk, and a control processing unit having an input-output interface connected with said tuner and said trunk opening actuator control unit, and a microprocessor for generating an output signal applied to said trunk opening actuator control unit on the basis of a signal from said tuner through said input-output interface, wherein said control processing unit wakes up said trunk opening actuator control unit upon receiving a signal for said antenna to place said trunk opening actuator in a controllable state and said microprocessor is configured to be awakened for a short time period when said antenna receives the signal in order to determine if the signal is or is not noise so that the trunk opening actuator control unit can be wakened for the first time if the signal is not noise.
10. An electronic control apparatus for a car, comprising a microcomputer configured to have low power consumption mode and to receive a plurality of signals including a signal from a remote controller at a wake-up terminal of said microcomputer, and
a tuner configured to send said signals from said remote controller to said wake-up terminal, said microcomputer being further configured to perform function checking as to whether, when a signal is inputted at said wake-up terminal of said microcomputer, the signal is or is not from one except said remote controller, said microcomputer being further configured to perform function checking as to whether a signal inputted at a digital input terminal of said microcomputer is or is not the correct signal from said remote controller, only when the signal inputted at said wake-up terminal was is not the signal from once except other that said controller, and said microcomputer being still further configured to be restored to a low power consumption mode as a result of the check function checking, when the signal has been decided as not being the correct signal form from said remote controller.
8. An electronic control apparatus for a car, comprising a microcomputer configured to have low power consumption mode and to receive a plurality of signals including a signal from a remote controller at a wake-up terminal of said microcomputer,
a communications interface configured to receive a signal for waking-up at least one selected control; device from said microcomputer and to output a wake-up signal to the at least one selected control device, said microcomputer being further configured to perform function checking as to whether, when a signal is inputted at said wake-up terminal of said microcomputer, the signal is from other than said remote controller, said microcomputer also being further configured to perform function checking as to whether a signal inputted at a digital input terminal of said microcomputer is the correct signal from said remote controller, only when the signal inputted at said wake-up terminal was not the signal from other than said remote controller, and as a result of the function check, when the signal has been decided as a correct signal from said remote controller, said microcomputer being still further configured to output the signal for waking up a selected control device at an output terminal of said microcomputer.
0. 15. An electronic control apparatus for a car, comprising:
a key switch connected to a battery having an accessory terminal for connecting said battery and a radio, an ignition terminal for connecting said battery and an engine controlling unit, and a starter switch for connecting said battery and a starter motor, a tuner connected to an antenna for receiving the signal from a remote control unit, control units directly applied with the electric power from said battery without going through said key switch, signal communication lines for transmitting a signal between said control units, a communication unit provided on each of said control units for effecting the transmission through said signal transmission lines, and at least one of said control units having the following, an input-output interface connected with said tuner and further operatively coupled to said accessory terminal, said ignition terminal and said starter switch, and a microprocessor for generating a sleep/wake-up signal to be applied to the at least one of said control units on the basis of the signal from said tuner through said input-output interface, said microprocessor being configured to be awakened for a short-time period upon reception by the antenna of a signal to determine if the signal is or is not noise, and then wake-up the at least one of said control units for the first-time when the signal is not noise.
11. An electronic control for a car, comprising a microcomputer configured to have a low power consumption mode and , a wake-up terminal and a digital signal terminal, a tuner for receiving the a signal from a remote controller, and said computer being configured to switch a power supply switchable between said low power consumption mode in which the power is intermittently supplied to said tuner and a normal power supplying mode in which the power is continuously supplied, wherein said microcomputer is further configured to receive a plurality of signals including a signal from a remote controller at said wake-up terminal,
said microcomputer being further configured to perform function checking as to whether, when a signal is inputted at the wake-up terminal of said microcomputer, the signal is or is not from said tuner so that, only when the signal inputted at said wake-up terminal is determined to be the signal from said tuner, a function for switching said power supply from said low power consumption mode to said normal power supplying mode, and a function for checking as to whether the signal from said tuner inputted at the digital input terminal of said microcomputer is or is not normal are executable, and said microcomputer being further configured to output the a signal for waking up a selected control device at the an output terminal of said microcomputer when the signal from said tuner inputted at the digital input terminal of said microcomputer is determined to be normal.
12. An electronic control for a car, comprising a microcomputer configured to have a low power consumption mode and a wake-up terminal and a digital signal terminal, a tuner for receiving the signal from a remote controller, and a power supply switchable between said low power consumption mode in which the power is intermittently supplied to said a tuner and a normal power supplying mode in which the power is continuously supplied, said microcomputer being further configured to receive a plurality of signals including the a signal from a remote controller at said wake-up terminal of said microcomputer, and
said tuner being configured to receive the signal from remote controller and to send said received signal to said wake-up terminal, said microcomputer being further configured to perform function checking as to whether, when a signal is inputted at said wake-up terminal of said microcomputer, the signal is or is not from said tuner, and only when the signal inputted at said wake-up terminal has been the signal from said tuner, a function for switching said power supply from said low power consumption mode to said normal power supplying mode, and a function for checking as to whether the signal from said tuner inputted at the digital input terminal of said microcomputer is or is not normal are executable, and said microcomputer being still further configured to restore said power supply to said low power consumption mode and to be shifted to said low power consumption mode when the signal from said tuner inputted at the digital input terminal of said microcomputer has been is determined as to be normal.
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This application is a continuation of application Ser. No. 08/651,559, filed May 22, 1996, now U.S. Pat. No. 5,744,874.
The present invention relates to an electronic control system for performing remote control over a car or vehicle with use of a radio signal such as radio wave or infrared ray, called keyless entry and more particularly, to an electronic control system for car remote control which switches between its sleep and operational modes as well as to a multiplex communication system employed for the electronic control system.
As a system for controlling supply of power to this type of electronic control system not having a remote control function, it is known as disclosed in JP-A-63-71451 to stop a terminal clock when power supply is unnecessary.
Also disclosed in JP-A-5-32142 is a system, when a microcomputer-controlled system is put in its sleep mode, for also causing a power supply for a watch dog timer to be automatically turned OFF, thus realizing reduction in its current consumption. Further, when it is desired to provide a remote control function to the electronic controller, such a power control system as to follow is considered.
An exemplary schematic arrangement of the power control system is shown in
Such another system as shown in
With the above prior art control unit for receiving the radio wave signal and controlling power supply based on the received signal, various types of electromagnetic waves are present in the air so that, even when the tuner fails to receive the normal radio wave signal, the tuner can issue an output signal. To avoid this, power supply to the tuner is intermittently carried out from an intermittent power supply 53' shown in
It is an object of the present invention to provide an electronic control system and method which can sufficiently suppress current consumption even in a high-noise application environment, and also to provide a multiplex communication system using the electronic control system or method.
In order to attain the above object, when a wake-up signal is input, an MPU is first operated even when the wake-up signal is a noise signal to merely judge whether or not the input signal is normal, and only after the MPU reliably judges that the input signal is a normal signal, the MPU is shifted to its usual operation. Further, when judging that the input signal is the noise signal prior to input of the full tuner signal, the MPU immediately shifts to a sleep mode.
With such an arrangement as mentioned above, since the need for provision of an oscillation circuit to a circuit for judgement of whether to be a wake-up signal can be eliminated, current consumption in the sleep mode can be suppressed. Further, even after the MPU starts its operation, the MPU is not shifted to a usual control operation until the MPU judges that the wake-up signal is normal. Thus, as soon as the MPU judges that the input signal is the noise signal, the MPU can be immediately shifted to the sleep mode, whereby the time duration of operation of the MPU can be minimized and current consumption can be suppressed even in a high noise state.
There is shown a block diagram of an arrangement of an electronic control system in accordance with a first embodiment of the present invention in
Shown in
The MPU 11 of the central processing unit 1 receives input signals from the switch units 35 and 36 and input signals from other sensors and terminal processors, calculates control data on motors, lamps, etc. connected to the central processing unit and on actuators of the other terminal processors, and outputs the calculated data thereto to perform entire control over the system. With such an in-car system, when the engine is stopped and no person rides in the car, the MPU stops oscillation of a clock within the MPU, turns. OFF the second and third power supply circuits 32 and 33, or stops oscillation of a clock within the terminal processor, for the purpose of suppressing the power consumption of the battery. The switches of the switch unit 36 include a door switch, a key insertion switch and an ignition switch. Since these switches are used to shift the sleep mode to the operational mode, it is necessary to detect the states of the switches even when the system is in the sleep mode. To this end, the switches are pulled up to the battery voltage or the voltage of the constant-voltage power supply circuit 30. The switches of the switch unit 35 include, for example, a wiper switch and a rear defogger switch which states will not change in the sleep mode. As for the rear defogger switch for example, this switch is operated only when the ignition switch is in its ON state, so that the ON state of the rear defogger switch means that the ignition switch is already turned ON before the defogger switch in turned ON and thus the system is in the operational mode. Thus, since it is unnecessary in the sleep mode to detect the states of the switches, the power to be supplied to the switches are set at the power of the second or third power supply circuit 32 or 33 which is turned OFF in the sleep mode. The tuner power supply circuit 39 is required to operate even in the sleep mode, but the continuous operation of the tuner power supply circuit at all times involves great current consumption. To avoid this, the tuner power supply circuit 39 is of an intermittent power supply type which supplies power intermittently in the sleep mode. The intermittent power supply circuit continuously supplies power during the operation of the MPU. The signals of the wake-up switch unit 36 and the output signal (tuner signal) of the tuner 38 for shifting the sleep mode to the operational mode are applied to the MPU and concurrently also to the logical gate 40. The logical gate 40 is connected at its output to a wake-up request terminal of the MPU to output a wake-up signal thereto so that, when receiving the wake-up signal, the MPU initiates the oscillation circuit 41 to start the wake-up operation.
Explanation will next be made as to the operation of the present embodiment by referring to a flowchart of FIG. 11. When the entire system is in the sleep mode, an input of a signal to the wake-up request terminal causes the MPU to start the wake-up operation of FIG. 11. More in detail, the system first judges at a step 101 whether or not the input signal to the wake-up request terminal is the wake-up signal from the tuner on the basis of signals other than the tuner signal applied to the terminals other than the wake-up request terminal. When determining the wake-up request from the non-tuner, the system transmits, at a step 105, the wake-up request to the other control units (terminal processors 3, 4 and 5 in the present embodiment) through the multiplex communication line 7. The terminal processors 3, 4 and 5, when receiving the wake-up signal, start their oscillating operation to start their main operation. At a next step 106, the system turns ON the second and third power supply circuits 32 and 33 to start power supply to the entire circuits. After this operation, the system starts usual control operation at a step 107. In this way, when the wake-up signal is other than the tuner signal, the signal carries less noise thereon and high frequency noise is eliminated by the hardware filter circuit. Thus, when the system judges at the step 101 the signal applied to the wake-up request terminal, the system can reliably determine it as a normal signal. Therefore, only once judgement causes the system to shift to the usual control. When judging at the step 101 that the input signal is from the tuner, the system determines the input signal is the wake-up request from the tuner and executes the operation of a step 102. Since the power supply to the tuner is intermittently carried out in the sleep mode, the input of the wake-up request signal causes the system to output a change-over signal for continuous power supply. With it, the system can judge whether or not the subsequent signal is rightly input. The system judges at a step 103 whether the tuner signal is normal or not until the system judges at a step 104 that the tuner signal was fully input. The tuner signal is set in the present embodiment to be constituted of 50 msec, or more of a header signal having a period of 5 msec, and a duty cycle of 50% followed by encoded ID code and command. When judging before the full input of this tuner signal that the tuner signal is abnormal, the system, at a step 108, performs sleep operation to cause the MPU to stop its oscillating operation and enter again into the sleep mode. Only when the tuner signal is fully input, the system executes the operations of the steps 105 and 106 to initiate the other control units and to turn ON the second and third power supply circuits 32 and 33 to supply power to the entire circuits, and then starts at the step 107 the usual control operation. In this way, only when the tuner signal is fully normally input, the entire system is shifted to the usual operational mode. Although the entire system has been set to be shifted to the usual operational mode only when the tuner signal is fully input in the present embodiment, the shift to the usual control operation may be carried out, e.g., when only the header signal is fully input or when part of the header signal is input.
Explanation will then be made as to the effects of the present embodiment. When power is intermittently supplied to the tuner, noise is also input due to the presence of any type of electromagnetic wave in the air. However, the noise is usually shifted in frequency band and has a pulse width much narrower than the normal signal. In addition, since the noise is eliminated by the hardware filter circuit, the noise will not be included in the wake-up request signal applied to the MPU. The noise, however, may have a pulse width similar to that of the normal signal. In such a case, the MPU wakes up. When the noise has such a waveform as shown in
In
In accordance with the present invention, since the control system is shifted to the usual operational mode only after the system judges whether or not a signal received at the receiver is the normal signal, even when the received signal contains much noise, the current consumption can be suppressed.
Although the embodiment of the present invention has been explained above in connection with
Reference numeral 1 denotes a control processing unit (CPU) (which will be referred to merely as the CPU 1, hereinafter), and numerals 3, 4, 5 and 69 denote terminal processors. The terminal processors are interconnected to each other by means of a multiplex communication line 7 so as to transfer input information on switches or input information on actuators such as motors or lamps connected to the associated terminal processors therebetween on a multiplex communication basis to thereby realize general control. The CPU 1 and terminal processors 3, 4, 5 and 69 are supplied with power directly from the battery regardless of the position of the ignition key switch. The CPU 1 includes a power supply circuit 67 made up of such constant-voltage power supply circuit 30, second power supply circuit 32 and third power supply circuit 33 as shown in
Explanation will next be made as to the operation of the keyless entry system. The `keyless entry system` as used herein refers to such a system as to lock or unlock car doors or to open or close the trunk room using a signal received from a radio device on a remote control basis. The keyless entry system, because of being operated on a remote control basis, is activated basically when no person rides in the car. When the key insertion switch is in its OFF state, i.e., when the key is not inserted, pushing of a lock switch of the transmitter causes the transmitter to transmit a lock signal (which will be detailed later). The signal is received at the antenna 37 and sent to the CPU 1. When CPU 1 judges that the received signal is the lock signal, the communication IC 12 in the CPU 1 issues via the multiplex communication line 7 to the communication ICs 8, 9, 10 and 70 of the terminal processors 3, 4, 5 and 69 such a signal as to drive the door lock motors 71, 75, 79 and 83 in such directions as to lock the associated doors respectively. The communication ICs 8, 9, 10 and 70 of the terminal processors 3, 4, 5 and 69, when receiving the aforementioned signal from the communication IC 12, output lock signals to the door lock motors 71, 75, 79 and 83 to lock the associated doors respectively. Similarly, pushing of an unlock switch of the transmitter causes the respective seat doors to be unlocked. Pushing of a trunk switch of the transmitter causes the CPU 1 to output a signal to the trunk opener motor connected to the CPU 1 per se to thereby open the trunk.
Generally speaking, such operations are carried out in such a manner that the transmitter user pushes the door lock switch on the transmitter when he or she gets off and leaves the car, the user pushes the transmitter door unlock switch while approaching the car to ride in, or the user pushes the transmitter trunk switch while approaching the car to put a shopping bag or bags in the trunk after shopping. To this end, as mentioned above, the CPU 1 and terminal processors 3, 4, 5 and 69 associated with the above are directly connected to the battery so as to be always supplied with power therefrom. Such a keyless signal, however, may be input immediately after the user leaves the car or may be input after a long period of time such as several hours or several days. In the latter case, the continuous energization of the terminal processors undesirably involves great current consumption. For the purpose of suppressing the power consumption of the battery, in this case, the terminal processors are put in the sleep mode. More specifically, the terminal processors are designed to be put in the sleep mode when the ignition key is in the OFF state or the key is not inserted yet, the doors are closed, no keyless signal is input, and all the loads are not activated at all. The operation of system in the sleep mode and the operation thereof in the wake-up mode have been already explained above and thus explanation thereof is omitted.
Next, the keyless entry system will be explained in more detail. Shown in
More in detail, the part A corresponds to a preamble part of the signal in which high and low levels are regularly repeated in the signal waveform. The preamble part A is used for the MPU 11 to judge whether the signal issued from the tuner 38 is a noise signal or a remote control signal or to stabilize the operation of the tuner circuit.
The part B is a data part which forms a pulse width modulation (PWM) signal. The data part corresponds to a command part of the remote control signal issued from the transmitter 68 (command signal part). The part B is made up of a data head indicative of the head of the data, 8 bits (from bit 7 to bit 0) of command portion, and a parity bit.
The bit details of the command portion has such a waveform that `0` and `1` are distinguished according to the pulse width, as shown in the drawing. More specifically, when the pulse width is (⅓)T (T:period), the pulse indicates `0`; whereas, when the pulse width is (⅔)T, the pulse indicates `1`. The interpretation of a command based on the distinguished `0` and `1` is known as "command signal analysis". The part B' similar to the part B is used to carry out again the command signal analysis in order to judge whether or not the result of the signal analysis of the part B by the MPU 11 is truly right. In other words, the part B' is used to judge whether or not the result of the signal analysis is employed depending on whether or not the signal analysis result of the part B coincides with the that of the part B'. That is, this means that two-successive signal collation is carried out. In this connection, it is unnecessary that the parts B and B' have exactly the same pattern. For example, an inversion of the signal of the part B may correspond to the part B' for inverted 2 successive-signal collation.
Differences between such regular right waveform, continuous waveform and irregular fine pulsative waveform as mentioned above are detected on the basis of differences in the pulse period of `Hi` and `Lo` or in the pulse width to determine whether the remote control radio signal was received or the remote control signal is a noise signal.
First of all, explanation will be made as to the types of noise to be removed. The noise shown in
When it is desired to restore an input signal, in general, the input signal is subjected to a sampling operation by a technique based on the sampling theorem to be restored according to the sampling period. However, if the noise position undesirably coincides with the sampling timing, then this means that it is impossible to execute the right sampling operation. To avoid this, the receiver is reduced in its sensitivity not to pick up the noise. This technique however, also makes it difficult to pick up not only the noise but also the normal signal, so this is not a good idea. In accordance with the present invention, after the input signal is sampled with a sampling period, the input signal is again confirmed after passage of a time sufficiently shorter than the sampling period, whereby noise can be easily removed.
Shown in
More specifically, when the tuner output signal received at the terminal PI of the MPU 11 has a "H" level in a step 201, the MPU 11 provides a predetermined delay time at a step 203. This delay time is necessary to set a time corresponding to a pulse width of high frequency noise to be removed. Subsequently at a step 204, the MPU 11 again examines the state of the terminal PI. This is when the MPU 11 determined that the terminal PI has an "L" level state at the step 204, that is, when the MPU 11 once recognized the terminal state is "H" but the state was changed after the passage of the time delay of the step 203. This means that the recognition of the state at the terminal PI carried out at the step 201 or 204 is invalid. That is, the signal picked up noise at the step 201 or 204. Thus, the MPU 11 returns to the step 201 to re-examine the state of the terminal PI. This operation is repeated until the state of the terminal PI before the delay time of the step 203 coincides with that after the delay time in a 2 successive collation manner. Thus it will be seen from this operation that noise having frequencies (or having pulse widths shorter than) smaller than the delay time set at the step 203 is ignored. The same holds true for steps 202 and 205 except that the logic of the terminal PI is reversed to the steps 203 and 204. Explanation will next be made as to how the signal is specifically changed by referring to
Turning again to the explanation of the fixed-time interrupt operation of
Subsequently, the MPU 11 increments the counter CT1 at a step 208 and clears a counter CT2 at a step 209. When the counter CT1 exceeds 4 at a step 210, the MPU 11 sets the flag HIOK at a step 211.
When the terminal PI is not in the "H" level state at the step 205, the MPU 11 checks at a step 212 whether or not the counter CT2 is 0. If 0 then the MPU 11 clears a flag LOOK at a step 213.
Then the MPU 11 increments the counter CT2 at a step 214 and clears the counter CT1 at a step 215. If the counter CT2 exceeds 4 at a step 216, then the MPU 11 sets the flag LOOK at a step 217.
The MPU 11 judges at a step 218 whether or not the flags HIOK and LOOK are both set. When the flags are set, the MPU 11 sets flag RCOK at a step 219, that is, judges that the input signal is the remote control signal. And at a step 220, the MPU 11 stops the fixed-time interrupt operation.
As mentioned above, the noise/signal distinction is carried out based on the pulse width or pulse period of the aforementioned part A of the "Hi" and "Lo". In the present embodiment, when the pulse width and period of the "Hi" and "Lo" are regularly repeated, the MPU 11 determines that the input signal is the remote control signal.
In this connection, the MPU 11 has a pulse width measuring function of storing time moments at which rising edges in the input signal the signal is applied to the terminal PI and at which a falling edge in the input signal the signal is applied to the terminal PI. Using this function, the MPU 11 usually can precisely measure the pulse width or period. To this end, such a technique as shown in
As has been explained above, in accordance with the present invention, the separation between the white noise and remote control signal is first carried out according to the procedure of FIG. 17 and then the analysis of the remote control signal is carried out using the pulse width measuring function of the MPU 11, which advantageously results in that, even when the system is used in a bad noisy environment, the analysis of the remote control signal can be accurately realized. In this connection, it is necessary that the fixed-time interval of the fixed-time interrupt operation, the counting frequency of the counters, etc. be adjusted according to the different waveforms of the remote control signal and noise or to the different sampling methods so as to positively realize the noise/signal distinction.
Next, explanation will be directed to the analyzing operation of the remote control signal.
Explanation will first be made as to the pulse width measuring function of the MPU 11.
Explanation will then be made as to hoe to measure the pulse width with reference to
Turning again to the signal analyzing operation of
When the signal analysis is not completed yet, the MPU 11 judges at a step 302 whether or not the analysis of the part A (preamble part) is completed. When the analysis is not completed yet, the MPU 11 goes to a step 400 to continuously execute the analysis of the part A. The analysis of the part A at the step 400 is for the purpose of reconfirming that the signal/noise distinction carried out in
When the detection of the part A is completed, the MPU 11 checks at a step 303 whether or not the analysis of the part B (data part) is completed. When the analysis of the part B is not completed yet, the MPU 11 continuously executes the analysis of the part B at a step 500. The key code analysis is actually carried out at this step 500.
The MPU 11 checks at a step 304 a difference between the signal and noise in the pulse width, pulse period and pattern or such an abnormality as the time-over of data frame. In the presence of an abnormality, the MPU 11 erases the analyzed command at a step 305. At the next step 306, the MPU 11 stops its own command signal analyzing operation, and initiates and completes at the step 307 the fixed-time interrupt operation.
Explanation will next be made as to the preamble analyzing operation of the step 400. In this operation, the part A of the remote control signal is analyzed as already mentioned above. The part A has such a regular correct square waveform having a duty cycle of 50% as shown in FIG. 14. In the present embodiment, only when such a signal part continues for a predetermined time TM1, the MPU 11 judges that the signal part corresponds to the head of the remote control signal.
Shown in
At a step 402, the MPU 11 judges whether the input edge is rising one or falling one. When the input edge is rising one, the MPU 11 waits for a certain time at a step 403. After this, the MPU 11 confirms the level of the input signal at the terminal PI at a step 404. When the input signal has a level of "L", that is, when the signal does not rise though the MPU 11 catches the rising edge in the input signal of the terminal PI, the MPU 11 can regard the caught signal as a high frequency noise signal. At this stage, the MPU 11 interrupts the operation and finishes the operation of the step 400 to get ready for a new input signal. Similarly, when the MPU 11 judges at the step 402 that the input edge is falling one, the MPU 11 goes to a step 405 to provide a delay time and then goes to a step 406 to confirm the level of the input signal. When the input signal has a level of "H" though the MPU 11 catches the falling edge, the MPU 11 judges the input signal is a high frequency noise signal and finishes the operation of the step 400.
The operations as far as this stage will be explained by referring to FIG. 23. The drawing shows a waveform of the remote control signal applied to the terminal PI, an enlarged waveform of the remote control signal having high frequency noise (such as car ignition noise or the like) carried thereon, and the effects of the respective steps 405 and 406. In general, high frequency noise is characterized by having a narrow pulsative width. Utilizing this feature, the present invention is designed to eliminate the noise. It is assumed in
When the falling edge of the signal is applied to the terminal PI and the MPU 11 initiates the signal analyzing operation of
Since the present invention can completely separate the high frequency noise from the normal remote control signal through such operations as mentioned above, the invention can provide a signal analysis technique which is immune to noise environment.
Turning again to
The storage of data in the time SVFRCT means to have determined a reference time. Further, since the terminal PI is set so as to catch the next falling edge, the terminal gets ready for the next falling edge.
An input of the falling edge causes the MPU 11 to pass through the step 402, 405 and 406 and to go to a step 413 to measure a time TP1. Symbol ICR denotes the value of the free-run timer caught by the latch circuit 1012 in FIG. 20. Accordingly, when the time SVFRCT is subtracted from the value ICR, a time necessary from the rising edge to the falling edge is found. It will be noted that the found necessary time corresponds to the pulse width of the "Hi" duration in the signal applied to the terminal PI. It will also be easily appreciated that the aforementioned pulse period TP2 corresponds to a time duration from the rising edge to the rising edge, i.e., the pulse period. Further, TP1L, TP1H and TP2L, TP2H are tolerance limit ranges for judgement of the input signal as a normal signal having the respective times TP1 and TP2. As will be seen, when the times TP1 and TP2 are within their tolerance ranges, the flags TP1OK and TP2OK are set; whereas, when the TP1 and TP2 are out of their tolerance ranges, these flags are cleared.
Shown in
It will be appreciated from the foregoing explanation that the preamble part analyzing/detecting operation of
Explanation will next be made as to the key code analyzing operation of the step 500 in FIG. 19. At a first step 501, the MPU 11 clears the timers TMR and TM1 and executes the timer TM2 start judging operation. The timer TMR similar to that used in the step 401 in
In this way, in accordance with the present invention, since a signal similar to the remote control signal is positively input, this helps improve the reception sensitivity; while, since the input data is examined on a multiple successive collation, this helps secure the data reliability, thus realizing provision of a noise-immune receiver.
When judging at the step 503 the input edge is rising one, the MPU 11 judges at steps 504 and 506 whether or not the rising edge position is normal. When the rising edge position is normal, this results in that TD3OK="1", whereas, when the rising edge position is abnormal, this results in that TD3OK="0". When the MPU 11 judges at a step 512 whether or not the flag TD3OK and pulse width are both normal. If the both are abnormal, then the MPU 11 goes to a step 518 to perform initializing operation and to retry the signal analyzing operation of
At a step 515, the MPU 11 judges the completion or non-completion of input of all the data. When determining the completion of the full data input, the MPU 11 goes to a step 516 to perform data collation. That is, the MPU 11 judges on a multiple successive collation basis whether or not the data parts inputted a plurality of times are the same. When this judgement result is OK, the MPU 11 proceeds to a step 518; whereas, when the result is NO, the MPU 11 goes to the step 519 to initialize the operation and to reentry the operation from the beginning.
Shown in
As has been explained in the foregoing, in accordance with the present invention, since a signal can be separated from noise while preventing the receiver sensitivity from being decreased, there can be provided a remote-controlled system which can exhibit its performance ability fully even in severe noise environment.
Yoshida, Tatsuya, Kon'i, Mitsuru
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