Abstract:
A door lock controller including input switches wherein, upon reception of a predetermined operational input to instruct locking or unlocking of a vehicle door, output signals thereof are switched from OFF to ON for a predetermined duration of time, and a microcomputer that locks or unlocks the vehicle door by drive control of a door lock motor upon detection of switching of the output signals that are output from the input switches from OFF to ON. In the door lock controller, upon return from a reset state to a normal operating state, the microcomputer is set up in such manner as to return with a forcible assumption that the output signals from the input switches is ON.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a door lock controller. 
     2. Description of the Related Art 
     FIG. 2 is a block diagram showing a conventional structure of a door lock controller that the invention is applied to. The door lock controller comprises input switches (operational input reception section)  1  and  3  for reception of a vehicle door locking or unlocking command and an electronic control unit  7  for drive control of a door lock motor  5  according to the input contents that are input through the input switches  1  and  3 . 
     The input switch  1  is a manual switch that is provided on inside of a door at a driver&#39;s seat for reception of a locking or unlocking command at on-off switching by the driver. The input switch  3  is a key-interlocked switch for reception of the locking or unlocking command at on-off switching that is interlocked with a locking or unlocking key operation at a key cylinder. 
     Each of the input switches  1  and  3  is provided respectively with two output signal lines  1   a  and  1   b , or  3   a  and  3   b , that are connected to input circuits  11  and  13 , or  15  and  17 , of the later-described electronic control unit  7 ; when the locking or unlocking command is not received, both of the output signals that come through the output signal lines  1   a  and  1   b  as well as  3   a  and  3   b  are maintained to be OFF and, upon reception of the locking signal, the output signals from the output signal lines  1   a  and  3   a  are switched from OFF to ON for a predetermined duration of time while, upon reception of the unlocking signal, the output signals from the output signal lines  1   b  and  3   b  are switched from OFF to ON for a predetermined duration of time (see FIGS.  3 ( a ) and  3 ( b )). 
     Both of the input switches  1  and  3  have a structure wherein an operating piece thereof  1   c  or  3   c  that is normally set at OFF position is switched to a-contact side or b-contact side for a predetermined duration of time upon reception of the locking or unlocking command, which causes the output signal lines la and  3   a  or  1   b  and  3   b  to be grounded for the predetermined duration of time and thus the output signals from the output lines  1   a  and  3   a  or  1   b  and  3   b  are caused to switch from OFF to ON for the predetermined duration of time. 
     The electronic control unit  7  comprises the input circuits  11 ,  13 ,  15  and  17  for reception of output signals from the input switches  1  and  3 , a microcomputer  19  for driving the door lock motor  5  according to the output signals from the input switches  1  and  3  which are received through the input circuits  11 ,  13 ,  15  and  17 , output circuits  21  and  23  for driving the door lock motor  5  according to the controls of the microcomputer  19 , and a power supply circuit  25  for generation of electric power source for the microcomputer  19 . 
     The input circuits  11 ,  13 ,  15  and  17  are respectively connected, at one end, to input ports Pa 1  through Pa 4  of the microcomputer  19  and, at the other end, after being branched into two, are connected to the positive side of a battery  27  and to corresponding output signal lines  1   a  and  1   b  as well as  3   a  and  3   b  of the input switches  1  and  3 . Accordingly, when the operating pieces  1   c  and  3   c  of the switches  1  and  3  are in the OFF position, all the input levels at the input ports Pa 1  through Pa 4  of the microcomputer  19  are high; when the operating pieces  1   c  and  3   c  are connected to the a-contact side, the inputs at the input ports Pa 1  and Pa 3  shift from a high level to a low level, and, when the operating pieces  1   c  and  3   c  are connected to the b-contact side, the inputs at the input ports Pa 2  and Pa 4  shift from the high level to the low level. 
     This causes the microcomputer  19  to recognize the switching from OFF to ON at the output signal from the input switch  1 , which corresponds to locking or unlocking, through detection of shifts in the inputs from the high level to the low level at input ports Pa 1  and Pa 2 , and to recognize the switching from OFF to ON at the output signal from the input switch  3 , which corresponds to locking or unlocking, through detection of shifts in the inputs from the high level to the low level at input ports Pa 3  and Pa 4 . 
     The output circuits  21  and  23  comprises: relays  21   a  and  23   a  for switching the connection of positive and negative power supply lines  5   a  and  5   b  for the door lock motor  5  either to the battery  27  side or to the ground side, and transistors  21   b  and  23   b  for driving the relays  21   a  and  23   a  in response to the shifts in the level of the outputs from the output ports Pb 1  and Pb 2  of the microcomputer  19  between the high level and the low level. 
     When the outputs from the output ports Pb 1  and Pb 2  of the microcomputer  19  are at the low level, the transistors  21   b  and  23   b  are turned off, and the relays  21   a  and  23   a  connect the power supply lines  5   a  and  5   b  for the door lock motor  5  to the ground. When the outputs from the output ports Pb 1  and Pb 2  of the microcomputer  19  shift to the high level, the transistors  21   b  and  23   b  are turned on and, the circuits being electrified with continuity from a positive terminal of the battery  27  to the ground via the relay coils  31  of the relays  21   a  and  23   a  and via transistors  21   b  and  23   b , the relay coils  31  being excited, the operating pieces  33  of the relays  21   a  and  23   a  switching from the ground-side contact to the battery-side contact, the relays  21   a  and  23   a  connect the power supply lines  5   a  and  5   b  for the door lock motor  5  to the positive terminal side of the battery  27 . The operating pieces  33  of the relays  21   a  and  23   a  are switched to the ground-side upon de-excitation of the relay coils  31  when the transistors  21   b  and  23   b  are turned off. 
     In a normal operating state, the microcomputer  19  controls the drive of the door lock motor  5  via the output circuits  21  and  23  through switching of the output state at the output ports Pb 1  and Pb 2 , according to the contents of input from the input ports Pa 1  through Pa 4 . 
     That is, the microcomputer  19  maintains the outputs at both of the output ports Pb 1  and Pb 2  to be low in a case of receiving neither locking commands nor unlocking commands from the input switches  1  and  3  while the output signals that are received from the input switches  1  and  3  through the input circuits  11 ,  13 ,  15  and  17  and the input ports Pa 1  through Pa 3  are OFF, wherein both the power supply lines  5   a  and  5   b  for the door lock motor  5  are connected to the ground by the relays  21   a  and  23   a.    
     When the output signals that are received from the input switches  1  and  3  through the input ports Pa 1  and Pa 3  are switched from OFF to ON for the predetermined duration of time upon reception of the locking commands from the input switches  1  and  3  as shown by A 1  and A 2  in FIGS.  3 ( a ) and  3 ( b ), the detection of switching from OFF to ON causes the microcomputer  19  to recognize the reception of the locking command and accordingly the door is locked by switching of the output level at the output port Pb 1  from the low level to the high level for the predetermined duration of time as shown by B 1  and B 2  in FIG.  3 ( c ) while the output at the output port Pb 2  is maintained at the low level. In a case wherein the output from the output port Pb 1  is switched to the high level at this time, since the power supply line  5   a  is connected to the positive terminal side of the battery  27  by the relay  21   a  , the electric current from the battery  27  flows from the power supply line  5   a  side to the motor  5  and forward drive (or reverse drive) of the motor for the predetermined duration of time effects locking of the door. 
     When the output signals that are received from the input switches  1  and  3  through the input ports Pa 2  and Pa 4  are switched from OFF to ON for the predetermined duration of time upon reception of the unlocking commands from the input switches  1  and  3  as shown by A 1  and A 2  in FIGS.  3 ( a ) and  3 ( b ), the detection of switching from OFF to ON causes the microcomputer  19  to recognize the reception of the unlocking command and accordingly the door is unlocked by switching of the output level at the output port Pb 2  from the low level to the high level for the predetermined duration of time as shown by B 1  and B 2  in FIG.  3 ( c ) while the output at the output port Pb 1  is maintained at the low level. In a case wherein the output from the output port Pb 2  is switched to the high level at this time, since the power supply line  5   b  is connected to the positive terminal side of the battery  27  by the relay  23   a , the electric current from the battery  27  flows from the power supply line  5   b  side to the motor  5  and the reverse drive (or forward drive) of the motor for the predetermined duration of time effects unlocking of the door. 
     Incidentally, the microcomputer  19  is provided with a setting section  19   a  for presetting and registration of initial data in advance for initial setting at startup or reset (for example, a setup information recording section, such as a ROM) so that the microcomputer  19  can be initialized and set up according to the initial data at the setting section  19   a  in the case of startup and reset. 
     In the conventional door lock controller with the structure as described above, the microcomputer  19  is so set up as to reset on forcible assumption that the output signals from the input switches  1  and  3  are OFF signals that are input through the input ports Pa 1  through Pa 4 . 
     Accordingly, in a case wherein the microcomputer  19  in the conventional door lock controller wherein the locking or unlocking command is input to the input switches  1  and  3  is reset due to such a mistake as caused by noise as shown by C 1  in FIG.  4 ( a ) during a period of time when the output signals from the input switches  1  and  3  are maintained to be ON as shown by A 2  in FIG.  4 ( c ), upon return to the normal operating state from the state wherein the reset is effected, as shown by D 1  in FIG.  4 ( d ), an erroneous recognition by the microcomputer  19  that the output signals from the input switches  1  and  3  have changed from OFF to ON, or an erroneous recognition that the locking command or the unlocking command has been received may result with erroneous output of the locking or unlocking command to the door lock motor  5 , as shown by B 3  in FIG.  4 ( e ). Consequently, in spite the fact that the locking command or unlocking command has been received only once from the input switch  3 , the door lock motor  5  carries out the locking or unlocking operation twice with the erroneous recognition that the command has been received twice and, since a user may recognize this as an erroneous operation, a problem is that the user is impressed with a sense of incongruity. 
     To describe the returning manner of the microcomputer  19  from the reset state more in detail, the microcomputer  19  is reset by noise or the like at time s 0  and the reset is cancelled at time s 1  and, when the microcomputer  19  starts initializing operation, the initializing operation forcibly sets the output signals that are input from the input switches  1  and  3  through the input ports Pa 1  through Pa 4  to be OFF by the initializing operation. Nextly, at time s 2 , upon completion of the initializing operation and return of the microcomputer  19  to the normal operating state, based on the contents of the initial setting, the microcomputer  19  forcibly assumes that the output signals that are input through the input ports Pa 1  through Pa 4  from the input switches  1  and  3  are OFF to return to the normal operating state. At time s 3 , when the microcomputer  19  detects actual output state (ON state) of the output signals that are input through the input ports Pa 1  through Pa 4  from the input switches  1  and  3 , in spite that the output signals have been maintained at ON, output for locking or unlocking is carried out with erroneous recognition of switching from OFF to ON. For the period from time s 0  to time s 2 , recognition contents of the output signals from the input switches  1  and  3  by the microcomputer  19  are undefined. 
     SUMMARY OF THE INVENTION 
     With consideration into the above-described problems, it is an object of the present invention to provide a door lock controller that enables prevention of erroneous double locking or unlocking operation by the door lock motor for each single input of locking or unlocking command in a case wherein the microcomputer is reset under influence of noise or the like. 
     In order to achieve the above object, according to the invention, there is provided a door lock controller comprising: an operational input reception section wherein, upon reception of a predetermined operational input to instruct locking or unlocking of a vehicle door, an output signal thereof is switched from OFF to ON for a predetermined duration of time; and a microcomputer that locks or unlocks the vehicle door by drive control of a door lock motor upon detection of switching of the output signal that is output from the operational input reception section from OFF to ON, wherein upon return from a reset state to a normal operating state, the microcomputer is set up in such manner as to return with a forcible assumption that the output signal that is input from the operational input reception section is ON. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a timing chart that shows the controlling operations of a door lock controller according to an embodiment of the invention; 
     FIG. 2 is a block diagram that shows conventional structure of the door lock controller; 
     FIG. 3 is a timing chart that shows the normal control operations of the door lock controller in FIG. 2; and 
     FIG. 4 is a timing chart that shows the controlling operations at the time of reset by noise or the like in the door lock controller in FIG.  2 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 is a timing chart that shows controlling operations by a door lock controller according to an embodiment of the invention. The door lock controller according to the embodiment has a basic hardware structure that is similar to the conventional structure that is shown in FIG.  2  and therefore, only the characterized parts of the door lock controller according to the embodiment are described here. 
     As FIG. 2 is referred to, in the door lock controller according to the embodiment, initial data that indicates that all the output signals that are input from the operational switches  1  and  3  through the input ports Pa 1  through Pa 4  are registered at the setting section  19   a  of the microcomputer  19  as the initial data that should be read as the output state of the output signals that are input from the operational switches  1  and  3  through the input ports Pa 1  through Pa 4  when the microcomputer  19  returns from a state of reset by influence of noise or the like to a normal operating state. 
     That is, in this embodiment, the microcomputer  19  is so set as to return from the reset state to the normal operating state with forcible assumption that all the output signals that are input from the operational switches  1  and  3  through the input ports Pa 1  through Pa 4  are ON. 
     Accordingly, in this door lock controller, the input switches  1  and  3  receive the locking command or the unlocking command and even in the case wherein the microcomputer  19  is reset erroneously by influence of noise or the like as shown by C 1  in FIG.  1 ( a ) during the period when the output signals from the input switches  1  and  3  are maintained to be ON as shown by A 2  in FIG.  1 ( c ), since the microcomputer  19  returns with forcible assumption that all the output signals that are input from the operational switches  1  and  3  through the input ports Pa 1  through Pa 4  as shown by D 2  in FIG.  1 ( d ), when the microcomputer  19  returns to the normal processing sate on the cancellation of the reset state shown by C 1  in FIG.  1 ( a ), the conventional erroneous double locking or unlocking operations of the door lock motor  5  for the input of the single locking or unlocking command, which is caused by erroneous recognition of the output signals from the input switches  1  and  3  changing from OFF to ON (that is, erroneous recognition of additional input of locking or unlocking command) by the microcomputer  19 . 
     To describe more in detail the return operation of the microcomputer according to the embodiment with references to FIG. 1, after the microcomputer  19  is reset by noise or the like at time s 0 , the reset is cancelled to start the initializing operation of the microcomputer  19  at time s 1  and, with the initialization, all the output signals that are input through the input ports Pa 1  through Pa 4  from the input switches  1  and  3  are forcibly set to ON. Upon completion of the initializing operation for return of the microcomputer  19  to the normal operating state at time s 2 , the microcomputer returns to the normal operating state with forcible assumption that all the output signals that are input from the input switches  1  and  3  through the input ports Pa 1  through Pa 4  are ON, based on the contents of the initial setting. Therefore, even in the case wherein the microcomputer  19  detects the actual output state (ON state) of the output signals that are input from the input switches  1  and  3  through the input ports Pa 1  through Pa 4  at time s 3 , the recognition by the microcomputer  19  that the output signals are ON remains true, and thus occurrence of conventional erroneous recognition can be prevented. 
     In a case wherein the microcomputer  19  is reset erroneously by influence of noise or the like, as shown by C 2  in FIG.  1 ( a ), when the output signals that are input from the operational switches  1  and  3  through the input ports Pa 1  through Pa 4  into the microcomputer  19  are OFF, the following operations are carried out for return. 
     After the microcomputer  19  is reset by noise or the like at time t 0 , the reset is cancelled to start the initializing operation of the microcomputer  19  at time t 1  and, with the initialization, all the output signals that are input through the input ports Pa 1  through Pa 4  from the input switches  1  and  3  are forcibly set to ON. Upon completion of the initializing operation for return of the microcomputer  19  to the normal operating state at time t 2 , the microcomputer returns to the normal operating state with forcible assumption that all the output signals that are input from the input switches  1  and  3  through the input ports Pa 1  through Pa 4  are ON, based on the contents of the initial setting. The microcomputer  19  detects the actual output state (OFF state) of the output signals that are input from the input switches  1  and  3  through the input ports Pa 1  through Pa 4  at time t 3 , and then the recognition on the output state of the output signals are changed to the actual output state (OFF) at time t 4 . In the period from time t 0  to time t 4 , no erroneous command for locking or unlocking will be output from the microcomputer  19 . Although the output signals from the input switches  1  and  3  are forcibly recognized as ON at time t 2 , the recognition by the microcomputer  19  on the output state of the output signals in the state at time t 2  or the before is not defined and therefore, no erroneous recognition of input of locking or unlocking command will occur. 
     As described above, in this embodiment, since the microcomputer  19  is so set as to return with forcible assumption that the output signals that are input from the input switches  1  and  3  are ON when the initial setting at the setting section  19   a  of the microcomputer  19  returns from the reset state to the normal operating state, in the case wherein the microcomputer  19  is reset by influence of noise or the like during the period wherein the output signals from the input switches  1  and  3  are switched to ON with input of the locking or unlocking signal, the microcomputer  19  is prevented from erroneously recognizing that the output signals have been switched from OFF to ON in spite that the output signals from the input switches  1  and  3  are maintained to be ON at the time of return from the reset state to the normal operating state, and this is effective in prevention of the user from being impressed with the sense of incongruity which is caused conventionally by double locking or unlocking operation for the door lock motor  5  against the single input of the locking or unlocking command in the case wherein the microcomputer  19  is reset by influence of noise or the like. 
     According to the invention, when returning from the reset state to the normal operating state, since the microcomputer is so set as to return with forcible assumption that the output signal that is input from the operational input reception section is ON, in the case wherein the microcomputer is reset by influence of noise or the like during the period wherein the output signal from the operational input reception section is switched to ON with input of the locking or unlocking command, the microcomputer is prevented from erroneously recognizing that the output signal has been switched from OFF to ON in spite that the output signal from the operational input reception section is so maintained to be ON as is conventional at the time of return from the reset state to the normal operating state, and this is effective in prevention of the user from being impressed with the sense of incongruity which is caused conventionally by double locking or unlocking operation for the door lock motor against the single input of the locking or unlocking command in the case wherein the microcomputer is reset by influence of noise or the like.