JP4062159B2 - Vehicle display device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle display device that drives display means in accordance with the state of a detection target in a vehicle, and more particularly to a vehicle display device that enables a circuit to be shared by a plurality of products having different specifications.
[0002]
[Prior art]
Conventionally, there is a display device 100 for displaying the operating state of the airbag control device 200, for example, as shown in FIG. In FIG. 5, the control circuit 10 in the display device 100 includes a microcomputer 11 and an EEPROM 12. The EEPROM 12 stores air bag wearing information as specification information set and input in advance. The microcomputer 11 performs display control (function) based on the air bag wearing information stored in the EEPROM 12. Or, it is selected (decided) whether or not to perform.
[0003]
When there is an airbag mounted and display control is selected, an H level or L level signal determined according to the output of the airbag control device 200 or the state of the wiring L1 is input to the port 11a. When the computer 11 inputs the H level signal to the port 11a, the computer 11 determines that an abnormality has occurred, outputs the H level signal to the port 11b, operates the display drive circuit 20, and turns on the light emitting diode 21.
[0004]
Here, when the air bag control unit 30 generates an H level signal, the transistor 201 is turned on to supply an L level signal to the microcomputer 11, while the air bag control unit 30 generates an L level signal. The transistor 201 is turned off, and an H level signal is given to the microcomputer 11 via the pull-up resistor 101.
[0005]
Further, when the transistor 201a of the airbag control device 200 is changed to the PNP type instead of the NPN type, the display device 100 shown in FIG. 6 uses the pull-down resistor 101a to generate the same signal as the display device 100 shown in FIG. In this example, the microcomputer 11 is provided.
[0006]
[Problems to be solved by the invention]
As described above, the control circuit 10 including the microcomputer 11 requires two ports 11 a for inputting a signal from the airbag control device 200 and a port 11 b for controlling the operation of the display driving circuit 20. The computer 11 is being given a large number of functions, and there is a possibility that a shortage of ports (that is, terminals for inputting and outputting) may occur.
[0007]
The present invention has been made in view of the above points, and an object of the present invention is to provide a vehicular display device capable of display control while saving the number of ports (that is, terminals for input and output) of a control circuit.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the technical means described in claim 1 is employed.
[0009]
According to the first aspect of the present invention, it is selected whether or not to perform display control based on preset specification selection information, and one level of signal differs depending on whether or not the display control is performed . a control circuit originating from the terminal, when a display driving circuit for driving the display device, the signal arising from said terminal a level for performing the display control, the state of the detection target signal without through the control circuit represents controls the operation of the pre-Symbol display drive circuit according to, when said signals originating from terminal becomes a level of the case of not performing the display control, regardless the display driving circuit in a state where the signal not through the control circuit represents a logic circuit for turning off the operation, characterized in that Ru comprising a.
[0010]
Thus, the control circuit can be provided with a signal generation function of a level determined based on the specification selection information , and the display control function can be provided in the logic circuit. Display control can be performed while saving the number of output terminals).
[0011]
According to the first aspect of the present invention, the control circuit has a rewritable nonvolatile memory that stores preset specification selection information, and outputs a signal at a level determined based on the stored contents of the nonvolatile memory. With the configuration generated from the terminal, it is possible to arbitrarily select the control specification of the display device by a write operation to the nonvolatile memory. For example, it is possible to reduce the number of product types by using a common display device. For example, specification selection information can be set in a non-volatile memory at the time of product shipment, and the degree of freedom in manufacturing can be increased.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to the drawings.
[0014]
FIG. 1 is a configuration diagram of a display device 100 that displays an operating state of the airbag control device 200, for example.
[0015]
The control circuit 10 includes a microcomputer 11 and an EEPROM 12 that is a rewritable nonvolatile memory. The microcomputer 11 comprehensively controls vehicle instruments including, for example, a vehicle speed, a coolant temperature, a fuel fuel gauge, various alarm indicators, and the like, and detection information from various sensors not shown. Is received from the input / output port (input / output terminal), and given calculation processing is performed. Then, the display control signal is sent from the input / output port (input / output terminal) to the instrument on the instrument panel in the vehicle cabin not shown Output and perform display control.
[0016]
In addition to the display items commonly displayed for each specification as described above, there are display items that are applied to a specific vehicle such as an airbag-equipped vehicle, for example, and a control circuit with different specifications depending on whether the airbag is installed 10 need to be prepared. Therefore, in order to make the control circuit 10 common, a plurality of control specifications are stored in advance in the storage device of the microcomputer 11, and the airbag mounting presence / absence information is used as specification selection information preset in the EEPROM 12 before vehicle shipment. Thus, the microcomputer 11 selects whether or not to perform display control on the basis of the airbag mounting presence / absence information stored in the EEPROM 12.
[0017]
In this example, the output port (output terminal) 11c of the microcomputer 11 is set so as to generate a signal of H level when the airbag is attached and L level when the airbag is not attached.
[0018]
The display drive circuit 20 receives the on-vehicle battery voltage VB, and causes the transistor 22 to turn on and display the light emitting diode 21 that is a display means. The diode 23 is for circuit protection when a reverse voltage is applied to the circuits 20 and 30.
[0019]
The logic circuit 30 includes transistors 31 and 32. When the H level signal is generated from the output port 11c, the logic circuit 30 generates the H level signal as the first signal S1. On the other hand, when the L level signal is generated from the output port 11c, the logic circuit 30 is nonconductive. A signal (substantially open) is generated as the first signal S 1 and applied to the wire connection point 34 through the resistor 33.
[0020]
The second signal S2 generated from the wiring L1 of the airbag control device 200 is an open signal when the wiring L1 is disconnected (opened) or a transistor when the airbag control unit 30 generates an H level signal. When 201 is turned on and an L level signal is generated on the collector side or the air bag control unit 30 generates an L level signal, the transistor 201 is turned off and a non-conducting (substantially open) signal is generated on the collector side.
[0021]
Therefore, both signals S1 and S2 are combined (in this case, logical product) at the wire connection point 34. Since the supply of the base current to the transistor 22 is determined by the first signal S1, the first signal S1 is prioritized. When the first signal S1 is at the H level, the second signal S2 is supplied as it is to the transistor 22 as the output signal S3, and the transistor 22 operates according to the second signal S2. On the other hand, when the first signal S1 is a non-conducting (substantially open) signal, the second signal S2 is directly supplied to the transistor 22 as the output signal S3. However, since the base current is not supplied from the transistor 32 side, the transistor 22 is turned off. Will remain.
[0022]
The operation of the above configuration will be described with reference to FIG. FIG. 2 is a table summarizing the lighting and extinguishing operations of the display device 100.
[0023]
When the airbag is installed, an H level signal is generated from the output port 11c of the microcomputer 11 on the basis of the specification selection information preset in the EEPROM 12, so that the transistors 31 and 32 are turned on, and the H level first signal S1. Produce. Therefore, when the wiring L1 of the airbag control device 200 is disconnected (open), the H-level third signal S3 is supplied to the transistor 22 and is turned ON, the light-emitting diode 21 is lit, and the driver or the like is inflated. The abnormality of the bag control device 200 is notified.
[0024]
Further, when the air bag control unit 30 generates an L level signal to notify a system abnormality or the like, and the transistor 201 is turned off, the H level third signal S3 is also given to the transistor 22 to be turned on. 21 lights up. However, when the system is normal, the air bag control unit 30 generates an H level signal and the transistor 201 is turned on. Therefore, the L level second signal S2 is directly applied to the transistor 22 as the third signal S3 and turned off. 21 is turned off.
[0025]
As described above, one output port 11c of the microcomputer 11 is used for display control, and a control signal having a level determined by the specification selection information preset in the EEPROM 12 is extracted from the output port 11c. In addition, since the display control function according to the state of the air bag control device 200 that has been conventionally performed in the microcomputer 11 is moved from the microcomputer 11 to the logic circuit 30 side, only one output port 11c is used. Thus, different display control specifications can be realized depending on whether or not the airbag is mounted.
[0026]
If the EEPROM 12 is built in the microcomputer 11, one more input / output port of the microcomputer 11 can be saved.
[0027]
Next, a modification of the above embodiment will be described with reference to FIG.
[0028]
The difference from the above embodiment is that the configuration of the logic circuit 30 using the transistor 35 and the PNP transistor 201a is used in the airbag control device 200, and the airbag control unit 30 generates an H level signal in the event of an abnormality. is there. A resistor 36 in the logic circuit 30 is a bias resistor for the transistor 35, and is also a pull-down resistor for fixing the potential on the base side when the wiring L1 is disconnected.
[0029]
The operation of the above configuration will be described with reference to FIG. FIG. 4 is a table summarizing the lighting / extinguishing operations of the display device 100.
[0030]
When the airbag is mounted, the first signal S1 of H level is generated from the output port 11c of the microcomputer 11 based on the specification selection information preset in the EEPROM 12. Therefore, when the wiring L1 of the airbag control device 200 is disconnected (open), the transistor 35 is turned off and the non-conducting signal S4 enters the wire connection point 34. Therefore, the H-level first signal S1 remains at the H level. Is supplied to the transistor 22 as the third signal S3 and turned on, and the light emitting diode 21 is turned on to notify the driver or the like of the abnormality of the airbag control device 200.
[0031]
Further, when the air bag control unit 30 generates an H level signal to notify an abnormality of the system and the transistor 35 is turned off, the H level third signal S3 is supplied to the transistor 22 and is turned on. 21 lights up. However, when the system is normal, the airbag control unit 30 generates an L level signal and the transistor 201a is turned on. Therefore, the transistor 35 is turned on by the H level second signal S2, and the L level third signal S3 is applied to the transistor 22. When given, the light-emitting diode 21 is turned off.
[0032]
The modification described above has an advantage that the number of transistors constituting the logic circuit 30 can be reduced by one as compared to the above-described embodiment, and the configuration can be simplified.
[0033]
In the above-described embodiment and modification, the NPN transistor 22 is used in the display drive circuit 20 and the transistor 22 is controlled to be turned on and off depending on whether or not the base current is supplied from the logic circuit 30. A transistor or a MOS transistor may be used, and the circuit may be configured so as to meet the control logic shown in FIGS.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of a display device showing an embodiment of the present invention.
FIG. 2 is a table summarizing operations of the display device shown in FIG.
FIG. 3 is an overall configuration diagram showing a modification of the display device shown in FIG. 1;
4 is a table summarizing operations of the display device shown in FIG. 3. FIG.
FIG. 5 is an overall configuration diagram of a display device showing a conventional technique.
FIG. 6 is an overall configuration diagram of a display device showing a conventional technique.
[Explanation of symbols]
10 control circuit 11 microcomputer 12 EEPROM (nonvolatile memory)
20 display drive circuit 21 light emitting diode 30 logic circuit 11c output port (output terminal)
100 Display Device 200 Airbag Control Device

Claims (1)

A rewritable nonvolatile memory (12) that stores preset specification selection information, and whether to perform display control based on the specification selection information stored in the nonvolatile memory (12), A control circuit (10) having a microcomputer (11) that generates signals at different levels depending on whether or not display control is performed from one terminal (11c);
A display drive circuit (20) for driving the display means (21);
When the signal generated from the terminal (11c) is at the level when the display control is performed, the display driving circuit (20) according to the state of the detection target represented by the signal (S2) not passing through the control circuit (10). When the signal generated from the terminal (11c) is at the level when the display control is not performed, the display drive is performed regardless of the state represented by the signal (S2) not through the control circuit (10). A logic circuit (30) for turning off the operation of the circuit (20);
A vehicle display device comprising:

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