JP2004241902A - On-vehicle wireless communication device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the reliability of a security system by an on-vehicle wireless communication device. <P>SOLUTION: The one-vehicle communication device has a microcomputer 5 which controls a wireless part 6 to transmit vehicle position information to a management sensor 20 of the security system, a watchdog timer 3 which outputs a WD setting signal to the microcomputer when the microcomputer 5 becomes abnormal, and a counter 4 which counts the output frequency of a WD resetting signal and controls a main power source part 1 to stop supplying electric power to the wireless part 6 when its count value exceeds a prescribed frequency 3. Consequently, the microcomputer 5 is reset each time the WD resetting signal is outputted until the output frequency of the WD resetting signal exceeds the prescribed frequency 3. The possibility that the microcomputer 5 is made to recover to normal operation becomes higher. Consequently, the possibility that the vehicle position information is transmitted can be improved. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an in-vehicle wireless communication device that performs a vehicle security function by wireless communication.
[0002]
2. Description of the Related Art
In recent years, vehicles have become more intelligent, and wireless communication devices for wirelessly connecting to an external communication network are often mounted on vehicles. On the other hand, theft of vehicles has become a social problem, and security functions such as tracking vehicles at the time of theft are essential.
[0003]
For example, in an in-vehicle wireless communication device, a microcomputer causes a management sensor of a security system to transmit vehicle position information at regular intervals by a wireless communication unit, and the management sensor stores the vehicle position information for each vehicle. What has been proposed. In this case, when the vehicle owner stolens the vehicle position information from the management sensor using a mobile phone or the like when the vehicle is stolen, the management sensor notifies the vehicle position information, so that the owner can track the vehicle. I can do it.
[0004]
Here, in order for the in-vehicle wireless communication device to constantly transmit the vehicle position information, it is necessary to always supply power to the microcomputer and the wireless communication unit from the in-vehicle battery. For this reason, when the vehicle position information is transmitted many times when the ignition switch is turned off (that is, when the vehicle-mounted generator is stopped), the vehicle-mounted battery may be depleted.
[0005]
Therefore, when the ignition switch is turned off, the vehicle position information is transmitted only a predetermined number of times (for example, once), and then the transmission of the vehicle position information is stopped, so that when the ignition switch is turned off (when the main power is turned off). It is conceivable to reduce the power consumption in ()).
[0006]
However, in this case, if an abnormality occurs in the microcomputer while the microcomputer is performing the process for transmitting the vehicle position information when the ignition switch is turned off, the vehicle position information is not normally transmitted, which is wasteful. Transmission may be repeated.
[0007]
For this reason, for example, when it is determined that an abnormality has occurred in the microcomputer even once, if the power supply from the vehicle-mounted battery to the microcomputer and the wireless communication unit is stopped, useless transmission repetition can be prevented. When the switch is turned off, it is considered that the vehicle position information may never be transmitted. Therefore, it is considered that the reliability of the security function of the vehicle-mounted wireless communication device is low.
[0008]
The present invention has been made in view of the above point, and an object of the present invention is to provide an in-vehicle wireless communication device that suppresses power consumption and improves reliability of a security function.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, according to the first aspect of the present invention, a wireless unit (6) for performing wireless communication and a position sensor of a vehicle are transmitted to a management sensor (20) of a security system. A microcomputer (5) for controlling the wireless unit, a power supply device (1) for supplying power to the microcomputer and the wireless unit, and determining whether an abnormality has occurred in the microcomputer when the main power of the vehicle is turned off. The reset means (3) for outputting a reset signal for resetting the microcomputer when it is determined that an abnormality has occurred in the microcomputer when the main power is off, and the reset means for outputting the reset signal when the main power is off. When the number of reset signal outputs is counted and the number of reset signal outputs is greater than or equal to two or more specified times, microcontroller A counter means (4) for controlling the power supply to stop the power supply to the computer and the radio unit, and having a.
[0010]
As a result, the microcomputer is reset every time the reset signal is output until the number of times the reset signal is output exceeds the prescribed number of times equal to or greater than two. Therefore, as described above, the possibility of resetting the microcomputer and returning to the normal operation is higher than when stopping the power supply to the microcomputer when it is once determined that an abnormality has occurred in the microcomputer. . Accordingly, the possibility that the position information can be transmitted to the management sensor when the main power supply is turned off increases, so that the reliability of the security function can be improved.
[0011]
Further, as described above, when the number of times of output of the reset signal exceeds the specified number, power supply to the microcomputer and the wireless unit is stopped, so that power consumption can be suppressed.
[0012]
Note that the microcomputer in this specification includes a digital signal processor.
[0013]
According to the second aspect of the present invention, when the microcomputer resets itself by a reset signal output from the reset unit when the main power is turned off and returns to the normal operation, the microcomputer counts the counter value of the number of outputs by the counter unit. It is characterized by being clear.
[0014]
In this case, the power supply device is controlled so that the power supply to the microcomputer and the wireless unit is stopped when the counter unit continuously counts the number of times of output of the reset signal equal to or more than two specified times.
[0015]
Further, as in the invention according to claim 3, the counter means stops power supply to the microcomputer and the radio unit when the number of times of output of the reset signal is cumulatively counted a specified number or more when the main power supply is turned off. The power supply device may be controlled as described above.
[0016]
Incidentally, reference numerals in parentheses of the above-mentioned units are examples showing the correspondence with specific units described in the embodiments described later.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows a schematic electric circuit configuration of a vehicle-mounted wireless communication device according to an embodiment of the present invention.
[0018]
As shown in FIG. 1, the in-vehicle wireless communication device includes a main power supply unit 1, an auxiliary power supply unit 2, a watchdog timer (WD timer) 3, a counter 4, a microcomputer 5, a radio unit 6, a memory 7, an antenna 8, It comprises a GPS receiver 9.
[0019]
The main power supply unit 1 is supplied with power directly from the vehicle-mounted battery B and generates a constant voltage to the microcomputer 5, the radio unit 6, and the memory 7, and outputs a constant voltage from the constant voltage unit 1a. And a relay switch 1b for stopping the output.
[0020]
The auxiliary power supply unit 2 is directly supplied with power from the vehicle battery B, and outputs a constant voltage to the watchdog timer 3 and the counter 4 at all times.
[0021]
The watchdog timer 3 determines whether or not an abnormality has occurred in the microcomputer 5 as described later. When it is determined that an abnormality has occurred in the microcomputer 5, a WD for resetting the microcomputer 5 is provided. Outputs reset signal.
[0022]
The counter 4 is, for example, a 2-bit counter circuit. The counter 4 counts the number of times the reset signal output from the watchdog timer 3 is output, and counts the number of outputs according to the count value to set the relay switch 1 b of the main power supply unit 1. Control.
[0023]
The radio unit 6 transmits an uplink communication signal to the base station 21 of the mobile communication network via the antenna 8 and receives a downlink communication signal from the base station 21 of the mobile communication network via the antenna 8.
[0024]
The GPS receiver 9 uses GPS (Global Positioning System) to calculate vehicle position information based on respective satellite signals received from a plurality of GPS artificial satellites via a GPS antenna (not shown). .
[0025]
The microcomputer 5 transmits the vehicle position information acquired from the GPS receiver 9 to the security system management center 210 via the base station 21 of the mobile communication carrier, and determines whether the microcomputer 5 itself is normal. A monitoring process or the like is performed to monitor the status at regular intervals.
[0026]
Here, the management center 210 stores the position information transmitted from the vehicle-mounted wireless communication device at regular intervals, notifies the vehicle position information in response to an inquiry from the vehicle owner, and notifies the vehicle of the stolen vehicle by the owner. Provides services that help track
[0027]
The memory 7 includes a flash memory, a DRAM, an SRAM, and the like, and stores data accompanying the processing of the microcomputer 5 and a computer program of the microcomputer 5.
[0028]
Next, the operation of the present embodiment will be described with reference to FIGS. 2, 3A to 3F.
[0029]
FIG. 2 is a flowchart showing the position information transmission processing by the microcomputer 5. 3A shows the state of the ignition switch (IG), FIG. 3B shows the output state of the main power supply unit 1, FIG. 3C shows the counter value of the counter 4, and FIG. FIG. 3E shows the output timing of the WD reset signal output from the watchdog timer, and FIG. 3F shows the output timing of the WD counter clear signal output from the microcomputer 5. Is shown.
[0030]
For example, when the ignition switch IG is turned on (activated), the counter 4 clears the counter value based on the switch signal from the ignition switch IG, and outputs a high-level signal as an ON signal to the relay switch 1b to relay the signal. Since the switch 1b is turned on, the output of the constant voltage from the constant voltage unit 1a to the microcomputer 5, the wireless unit 6, and the memory 7 is started.
[0031]
Accordingly, the microcomputer 5 executes the computer program according to the flowchart shown in FIG. First, it is determined whether or not the ignition switch IG is turned on based on a switch signal output from the ignition switch IG (step 100).
[0032]
Here, when the switch signal output from the ignition switch IG is equal to or higher than a predetermined level, it is determined that the ignition switch IG is turned on, that is, the main power of the vehicle is turned on, and the determination is YES (FIG. 3B). At the middle timing {circle around (1)}, the vehicle position information acquired from the GPS receiver 9 is transmitted by the wireless unit 6 through the antenna 8 (step 110).
[0033]
As a result, the vehicle position information is sent to the management center 20 through the base station 21, and the vehicle position information for each vehicle is stored by the management center 20. Such a process of transmitting the vehicle position information to the management center 20 is performed at regular intervals while the ignition switch IG is turned on.
[0034]
Thereafter, when the ignition switch IG is turned off (stopped), that is, when the main power supply of the vehicle is turned off, NO is determined in step 100, and after waiting for a predetermined period (for example, 30 seconds), transmission of the vehicle position information is performed as in step 110. The process (step 130) is performed only once.
[0035]
Here, during the process of transmitting the vehicle position information (step 130), the microcomputer 5 monitors at regular intervals whether or not the transmission process is normally performed.
[0036]
Specifically, it is determined at regular intervals whether or not computation data associated with the transmission processing of the vehicle position information is obtained within a certain period, and when the computation data is obtained within a certain period, the microcomputer 5 It determines that itself is normal and outputs a WD clock signal. If the calculation data associated with the transmission processing of the vehicle position information cannot be obtained within a certain period, the microcomputer 5 determines that the microcomputer 5 is abnormal and stops outputting the WD clock signal.
[0037]
Note that the abnormality of the microcomputer 5 is assumed to be an abnormality of each register constituting the microcomputer 5, an abnormality of the computer program itself, an abnormality of the memory 7, and the like.
[0038]
As a result, when the position information transmission process is performed normally, the WD clock signal is output at regular intervals (see timings (2) to (3) and (3) in FIG. 3D). (Refer to the period from 5 to 7)).
[0039]
Here, the watchdog timer 3 determines whether the microcomputer 5 itself is normal or not at regular intervals by determining whether the WD clock signal is output from the microcomputer 5 at regular intervals. Will do.
[0040]
When an abnormality occurs in the microcomputer 5 and the output of the WD clock signal is stopped at regular intervals (see timing 4 in FIG. 3D), the watchdog timer 3 A WD reset signal for resetting the microcomputer 5 by judging that an abnormality has occurred is output to the microcomputer 5 (see timing (4) in FIG. 3 (e)).
[0041]
Accordingly, when the microcomputer 5 attempts resetting based on the WD reset signal and returns to the normal operation, the processing of the position information transmission processing is started again. Then, the microcomputer 5 restarts outputting the WD clock signal every fixed period (see timings (5) and (7) in FIG. 3D).
[0042]
Here, when the watchdog timer 3 outputs the WD reset signal as described above, the counter 4 counts "1" as the number of times the WD reset signal is output (see timing (4) in FIG. 3 (c)). Then, the counter value "one time" is cleared based on the WD counter clear signal output from the microcomputer 5.
[0043]
Thereafter, the output of the WD clock signal from the microcomputer 5 is stopped (refer to timing (7) and thereafter in FIG. 3E), and the watchdog timer 3 determines that the microcomputer 5 has failed. A WD reset signal is output to the microcomputer 5 each time the lever is determined (see timings (8) and (9) in FIG. 3E).
[0044]
However, if the microcomputer 5 does not return to the normal operation and the watchdog timer 3 determines three times consecutively that the microcomputer 5 has failed, the counter 4 is output from the watchdog timer 3 for each failure determination. The number of times the WD reset signal is output is counted as “3 times”. At this time, since the watchdog timer 3 outputs a low-level signal as an OFF signal to the relay switch 1b of the main power supply unit 1, the relay switch 1b is turned off and the microcomputer 5, the wireless unit 6, the memory 5, and the constant voltage unit 1a are turned off. The output of the constant voltage to 7 is stopped.
[0045]
As described above, according to the present embodiment, when it is determined three times consecutively that an abnormality has occurred in the microcomputer 5, the power supply to the microcomputer 5, the wireless unit 6, and the memory 7 is stopped. On the other hand, if it is determined that the microcomputer 5 itself is normal during the execution of the position information transmission process, the vehicle position information is transmitted only once.
[0046]
Then, according to the present embodiment, the microcomputer 5 is reset every time the WD reset signal is output until the number of times the WD reset signal is output exceeds the specified number of times 3. Therefore, the microcomputer 5 can be reset and returned to the normal operation when the power supply from the main power supply unit 1 to the microcomputer 5 is stopped when it is determined that the microcomputer 5 has failed once. The nature becomes high. Accordingly, the possibility that the vehicle position information can be transmitted to the management sensor 20 when the ignition switch IG is turned off increases, so that the reliability of the vehicle security function (stolen vehicle tracking function) can be improved. .
[0047]
Further, as described above, when the number of times of output of the WD reset signal exceeds the specified number of times 3, the power supply to the microcomputer 5 and the wireless unit 6 is stopped, so that power consumption can be suppressed.
[0048]
(2nd Embodiment)
In the above-described embodiment, the example in which the counter 4 outputs the OFF signal to the relay switch 1b of the main power supply unit 1 when the watchdog timer 3 determines that the microcomputer 5 has failed three times in succession. Alternatively, the counter 4 outputs an OFF signal when the counter 4 cumulatively determines that an abnormality has occurred in the microcomputer 5 three times. FIG. 4 shows an electric circuit configuration of the in-vehicle wireless communication device in this case.
[0049]
The in-vehicle wireless communication device according to the present embodiment includes an OR gate 10 that is directly supplied with power from the in-vehicle battery B. When the ignition switch IG is turned on, the OR gate 10 turns on the ON signal described in the above embodiment. To the relay switch 1b of the main power supply unit 1. When receiving the OFF signal from the counter 4, the OR gate 10 outputs the OFF signal to the relay switch 1b. In FIG. 4, the same reference numerals as those in FIG. 1 denote the same components. In FIG. 4, the auxiliary power supply unit 2 shown in FIG. 1 is deleted.
[0050]
In the present embodiment, when the microcomputer 5 resets based on the WD reset signal (see timing (4) in FIG. 5E) output from the watchdog timer 3 and returns to the normal operation, the microcomputer 5 transmits the position information. Although the processing is started again, the WD counter clear signal is not output.
[0051]
Accordingly, even if the transmission process of the position information is started again, the counter value of the counter 4 is not cleared, and thereafter, the microcomputer 5 becomes abnormal and the watchdog timer 3 outputs the WD reset signal twice. When the counter 4 counts the number of times the WD reset signal is output as "3" (see timings (7) and (8) in FIG. 5E), the counter 4 outputs the OFF signal to the relay switch 1b of the main power supply unit 1. Output. Therefore, the relay switch 1b is turned off, and the output of the constant voltage from the constant voltage unit 1a to the microcomputer 5, the wireless unit 6, and the memory 7 is stopped.
[0052]
As described above, when the counter 4 cumulatively determines that the microcomputer 5 has failed three times, the constant voltage output from the constant voltage unit 1a to the microcomputer 5, the wireless unit 6, and the memory 7 is output. Will be suspended.
(Other embodiments)
In each of the above-described embodiments, an example has been described in which the number of times that the vehicle position information is transmitted to the management center 20 when the ignition switch IG is turned off is one, but instead, the ignition switch IG is turned off. At this time, the number of times of transmitting the vehicle position information to the management center 20 may be one or more fixed times.
[0053]
In each of the above-described embodiments, when the number of times the WD reset signal is output is counted as "3", the relay switch 1b is turned off and the constant voltage from the constant voltage unit 1a to the microcomputer 5, the wireless unit 6, and the memory 7 is output. An example in which the output is stopped has been described. Alternatively, when the number of times the WD reset signal is output is counted a predetermined number of times other than “three” (for example, two or three or more times), the relay may be stopped. The switch 1b may be turned off and the output of the constant voltage from the constant voltage unit 1a to the microcomputer 5, the wireless unit 6, and the memory 7 may be stopped.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an electric circuit configuration of a vehicle-mounted wireless communication device according to a first embodiment of the present invention.
FIG. 2 is a flowchart showing the operation of the microcomputer of FIG.
FIG. 3 is a time chart showing the operation of each circuit in FIG. 1;
FIG. 4 is a block diagram illustrating an electric circuit configuration of a vehicle-mounted wireless communication device according to a second embodiment of the present invention.
FIG. 5 is a time chart showing the operation of each circuit of FIG. 4;
[Explanation of symbols]
1 ... Main power supply unit, 2 ... Auxiliary power supply unit, 3 ... Watch dock timer,
4 counter, 5 microcomputer, 6 radio unit, 7 memory,
8 ... antenna, 9 ... GPS receiver.

Claims (3)

A wireless unit (6) for performing wireless communication;
A microcomputer (5) for controlling the wireless unit to transmit the vehicle position information to the management sensor (20) of the security system;
A power supply device (1) for supplying power to the microcomputer and the wireless unit;
When the main power of the vehicle is off, it is determined whether or not an abnormality has occurred in the microcomputer, and when it is determined that an abnormality has occurred in the microcomputer when the main power is off, the microcomputer is reset. Reset means (3) for outputting a reset signal;
Counting the number of outputs of the reset signal output from the reset means when the main power is off, and when counting the number of outputs of the reset signal is equal to or more than two specified times, power is supplied to the microcomputer and the wireless unit. And a counter means (4) for controlling the power supply device to stop. When the microcomputer resets itself by a reset signal output from the reset unit when the main power is turned off and returns to a normal operation, the microcomputer clears a counter value of the number of outputs by the counter unit. The in-vehicle wireless communication device according to claim 1, wherein: The counter means controls the power supply device to stop supplying power to the microcomputer and the radio unit when the number of outputs of the reset signal is cumulatively counted over the specified number of times when the main power supply is turned off. The in-vehicle wireless communication device according to claim 1, wherein:

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