JP2017054306A - Vehicle display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle display device which can hold specific data to be stored in a NAND flash memory, for a long time.SOLUTION: A display device periodically overwrites image data in a NAND flash memory by means of GDC. In the NAND flash memory, electric charge decreases gradually with time, and data is lost, while the electric charge can be refreshed by overwriting the data. Image data is overwritten periodically, thereby preventing the image data from being lost with time. Accordingly, image data can be held for a long time.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a vehicle display device mounted on a vehicle.

  The vehicle display device is mounted on a vehicle and displays vehicle information so as to be visible to the driver. Examples of vehicle information displayed by the vehicle display device include a vehicle speed, an engine speed, a remaining fuel amount, a coolant temperature, and operating states of various switches. As such a vehicle display device, a digital meter that displays vehicle information by an image formed on a liquid crystal panel is widely used.

  An image displayed by the vehicle display device is stored in advance in a flash memory. Features of the flash memory include that it is possible to reduce the size and that the reliability is increased because a driving device is unnecessary. In particular, NAND flash memories that can be easily increased in capacity are rapidly spreading as information recording media. A NAND flash memory is a kind of flash memory, and is characterized by being inexpensive and capable of high-speed erasing and writing.

  However, the NAND flash memory has a limit on the number of times data can be erased and written due to its electrical characteristics. A flash memory is composed of a plurality of blocks, but it is necessary to control a data storage method so that erasure and writing of data to a specific block are not concentrated. And in patent document 1, the deterioration diagnosis of flash memory is regularly performed and the diagnosis result is notified.

JP 2013-123926 A

  Although the deterioration diagnosis of the data described in Patent Document 1 is performed, no method for suppressing the deterioration is described. Among data stored in the flash memory of the vehicle display device, there is data that cannot be rewritten after being written once at the time of manufacture, such as a background image of a meter. When a NAND flash memory is used for such data, the data retention period is about 5 years in the operating temperature range of the vehicle display device, which is 12 years, the required memory retention period for in-vehicle devices. There is no problem.

  Accordingly, the present invention has been made in view of the above-described problems, and an object thereof is to provide a vehicle display device that can hold specific data stored in a NAND flash memory for a long period of time. .

  The present invention employs the following technical means in order to achieve the aforementioned object.

  The present invention reads out NAND flash memory (44), NOR flash memory (45), image data stored in the NAND flash memory and NOR flash memory, and displays an image displayed on the display unit. And a control unit (43) to be generated. The control unit is a vehicle display device that periodically overwrites image data in a NAND flash memory.

  According to the present invention as described above, the image data of the NAND flash memory is periodically overwritten by the control unit. In the NAND flash memory, the charge gradually decreases and data disappears as time elapses, but the charge can be refreshed by overwriting the data. Therefore, by periodically overwriting the image data, it is possible to suppress the disappearance of the image data over time. As a result, the image data can be held for a long time. A NAND flash memory is suitable for storing image data because it has a large capacity and is inexpensive. The NOR flash memory is expensive but has a larger number of rewrites than the NAND flash memory, and is excellent in practicality. By reducing the storage capacity of such a NOR type flash memory and using it together with a large capacity NAND type flash memory, the disadvantages of both can be compensated and the advantages can be utilized. Therefore, the NAND flash memory and the NOR flash memory can be suitably used for the vehicle display device.

  In addition, the code | symbol in the bracket | parenthesis of each above-mentioned means is an example which shows a corresponding relationship with the specific means as described in embodiment mentioned later.

4 is a front view showing a display device 40. FIG. 1 is a block diagram showing an in-vehicle network 10. FIG. It is a flowchart which shows the data holding process of GDC43. It is a figure which shows the error process of GDC43.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS. First, the electrical configuration of the host vehicle 100 will be described. As shown in FIG. 2, the in-vehicle network 10 includes a periphery monitoring system 20, a vehicle control system 30, a display device 40, a communication bus 50 to which these are connected, and the like. Each system of the in-vehicle network 10 is connected via a communication bus 50 via an in-vehicle network such as a LAN (Local Area Network).

  The periphery monitoring system 20 includes external sensors such as a front camera unit 21 and a radar unit 22, and a periphery monitoring ECU (Electronic Control Unit) 23. The perimeter monitoring system 20 is used for moving objects such as pedestrians, non-human animals, bicycles, motorcycles, and other vehicles, as well as falling objects on the road, traffic signals, guardrails, curbs, road signs, road markings, and trees. Such a stationary object is detected. The periphery monitoring system 20 can include external sensors such as lidar and sonar in addition to each unit.

  The front camera unit 21 is a monocular or compound eye camera installed in the vicinity of the rearview mirror of the host vehicle 100, for example. The front camera unit 21 is directed in the traveling direction of the host vehicle 100, and can capture a range of about 80 meters from the host vehicle 100 at a horizontal viewing angle of about 45 degrees, for example. The front camera unit 21 sequentially outputs captured image data showing a moving object and a stationary object to the periphery monitoring ECU 23.

  The radar unit 22 is installed in the front part of the host vehicle 100, for example. The radar unit 22 emits a 77 GHz millimeter wave toward the traveling direction of the host vehicle 100 from the transmission antenna. The radar unit 22 receives millimeter waves reflected by a moving object and a stationary object in the traveling direction by a receiving antenna. The radar unit 22 can scan a range of about 60 meters from the own vehicle 100 at a horizontal scanning angle of about 55 degrees, for example. The radar unit 22 sequentially outputs scanning information based on the received signal to the periphery monitoring ECU 23.

  The periphery monitoring ECU 23 is mainly configured by a microcomputer having a processor and a memory. The periphery monitoring ECU 23 is connected to the front camera unit 21, the radar unit 22, and the communication bus 50 so as to be communicable. The surrounding monitoring ECU 23 detects the relative positions of a moving object and a stationary object in the traveling direction by integrating information acquired from each unit. Specifically, the periphery monitoring ECU 23 extracts an object shown in the image data of the front camera unit 21 by image processing. Then, the periphery monitoring ECU 23 calculates the relative position of the extracted detected object such as a moving object and a stationary object based on the scanning information of the radar unit 22. The surrounding monitoring ECU 23 calculates the moving direction and moving speed of the moving detection object based on the transition of the relative position.

  The vehicle control system 30 includes an operation detection sensor such as an accelerator position sensor 31, a brake pedal force sensor 32, and a steering angle sensor 33, and a vehicle control ECU 34. The vehicle control system 30 controls the travel of the host vehicle 100 based on the input by the driver seated in the driver's seat and the detection result of the periphery monitoring system 20.

  Each sensor is connected to the vehicle control ECU 34. The accelerator position sensor 31 detects the amount of depression of the accelerator pedal by the driver, and outputs it to the vehicle control ECU 34. The brake pedal force sensor 32 detects the pedal force of the brake pedal by the driver, and outputs it to the vehicle control ECU 34. The steering angle sensor 33 detects the steering angle amount of the steering by the driver and outputs it to the vehicle control ECU 34.

  In addition, the vehicle control system 30 is provided with one or more types of sensors for detecting the traveling state of the other host vehicle 100, such as a vehicle speed sensor, a rotation speed sensor, a fuel sensor, a water temperature sensor, and a radio wave receiver. ing. Specifically, the vehicle speed sensor detects the vehicle speed of the host vehicle 100, and outputs a vehicle speed signal corresponding to the detection. The rotation speed sensor detects the engine rotation speed in the host vehicle 100 and outputs a rotation speed signal corresponding to the detection. The fuel sensor detects the remaining amount of fuel in the fuel tank of the host vehicle 100, and outputs a fuel signal corresponding to the detection. The water temperature sensor detects the coolant temperature of the internal combustion engine in the host vehicle 100, and outputs a water temperature signal corresponding to the detection. The radio wave receiver outputs a traffic signal by receiving output radio waves from, for example, a positioning satellite, another vehicle transmitter for vehicle-to-vehicle communication, and a roadside device for road-to-vehicle communication. Here, the traffic signal is a signal indicating traffic information related to the host vehicle 100 such as a travel position, a travel direction, a travel path state, a speed limit, and the like.

  The vehicle control ECU 34 is mainly composed of a microcomputer having a processor and a memory. The vehicle control ECU 34 is connected to the communication bus 50. The vehicle control ECU 34 is one or more types including at least an integrated control ECU among an engine control ECU, a motor control ECU, a brake control ECU, an integrated control ECU, and the like. The vehicle control ECU 34 outputs vehicle information indicating a traveling state such as a detection result of each sensor and a traveling speed of the host vehicle 100 to the communication bus 50.

  The display device 40 includes a meter 41, a large capacity display 42 such as a multi function display (MFD), a graphic display computer (abbreviated as GDC) 43, a NAND flash memory 44, and a NOR. A type flash memory 45 and a meter control circuit 46 are provided. The display device 40 is a vehicle display device mounted on a vehicle, and provides vehicle information related to the traveling state of the host vehicle 100 to passengers of the host vehicle 100 including a driver. The display device 40 can include an operation device that operates display of each display device.

  The meter 41 and the indicator 42 are installed on the instrument panel in the passenger compartment. The large-capacity display 42 is a display unit, and displays a real image of an image formed so as to show predetermined information on one or a plurality of liquid crystal panels so that the driver can visually recognize it. As such a real image display by the display 42, display of an image indicating one type or a plurality of types of information among navigation information, audio information, video information, communication information, operation states of various switches, and the like is employed.

  The meter 41 displays vehicle information related to the host vehicle 100 so that the driver can visually recognize the vehicle information. In this embodiment, the meter 41 is an analog meter that displays vehicle information by indicating a scale with a pointer. The meter 41 is not limited to an analog meter, and may be a digital meter that displays vehicle information using an image formed on a liquid crystal panel. As such a display by the meter 41, for example, a display indicating one type or a plurality of types of information among the vehicle speed, the engine speed, the remaining amount of fuel, the coolant temperature, the operation states of various switches, and the like is employed.

  The meter control circuit 46 is mainly composed of a microcomputer having a processor and a memory. The meter control circuit 46 is connected to the communication bus 50. The meter control circuit 46 acquires vehicle information such as the vehicle speed output to the in-vehicle LAN via the communication bus 50. Further, the meter control circuit 46 is also electrically connected to a drive source that drives the pointer of the meter 41. The meter control circuit 46 performs control based on energization to the drive source, for example, vehicle information obtained as a current value. The drive source is composed of a step motor or the like capable of generating a rotational output, and rotationally drives the pointer by generating a rotational output by energization. As a result, the pointer is arranged at the rotational position based on the vehicle information.

  The GDC 43 is a control unit and controls an image displayed by the display 42. The GDC 43 is connected to the communication bus 50. The GDC 43 is a drawing processor and is configured mainly with a microcomputer. The GDC 43 is connected to the NAND flash memory 44 and the NOR flash memory 45, reads out the image data from each of the flash memories 44 and 45, and generates an image to be displayed on the display 42. Specifically, the GDC 43 executes the operation control based on the acquired information and control information in the periphery monitoring ECU 23 and the vehicle control ECU 34, the stored information in the flash memories 44 and 45, and the like.

  The NAND flash memory 44 is a NAND flash memory. The NAND flash memory 44 stores a plurality of relatively large-capacity image data such as background data.

  The NOR type flash memory 45 is a NOR type flash memory. The NOR flash memory 45 stores a plurality of image data having a relatively small capacity such as component data. The storage capacity of the NAND flash memory 44 is set to be larger than the storage capacity of the NOR flash memory 45.

  As shown in FIG. 1, on the display 42, the background image 42a displays the engine speed 42b, a display indicating the state of the lane keep assist 42c, a display indicating the state of the air conditioner 42d, a shift position 42e, and the like. . Among such images, images having a large capacity or fixedly displayed, such as the background image 42 a and the image 42 f of the host vehicle 100 as described above, are stored in the NAND flash memory 44. Other images, for example, an image indicating a numerical value and an image indicating a shift position are stored in the NOR flash memory 45.

  Next, the holding control for holding the memory of the NAND flash memory 44 of the GDC 43 will be described with reference to FIG. FIG. 3 shows control that is periodically executed in a state where power is supplied to the GDC 43.

  In step S1, it is determined whether or not the display unit 42 is in use. If the display unit 42 is in use, this flow is terminated. If the display unit 42 is not in use, the process proceeds to step S2. The display 42 being used is a state in which an image is displayed on the display 42.

  In step S2, since the display device 42 is not in use, it is determined whether or not the rewrite condition is satisfied. If the rewrite condition is satisfied, the process proceeds to step S3, and if the rewrite condition is not satisfied, This flow ends. The rewrite condition is set so that it is less than the data retention life of the NAND flash memory 44 and the rewrite count does not exceed the rewrite limit count. The rewriting condition is satisfied, for example, when a certain travel distance, for example, 2000 km has been exceeded since the last rewriting, for a certain period of time, for example, two years since the last rewriting, and when the battery is reconnected.

  In step S3, since the rewrite condition is satisfied, control is performed so that the data stored in the NAND flash memory 44 is overwritten, and this flow ends. Since the data retention period is reset by overwriting and updating the data in this way, it is possible to prevent the data from being lost over time. The rewrite condition is set so as not to exceed the rewrite limit number. For example, when the vehicle life is set to 12 years and the limit mileage is set to 150,000 km, if the rewrite limit number is 10, the rewrite limit number is not exceeded even if the data is updated every two years. Similarly, even if the data is updated every 2,000 km of travel distance, the rewrite limit number is not exceeded.

  As a method for overwriting data, for example, the NAND flash memory 44 stores image data and its copy data. The image data is overwritten with the copy data and updated, and the copy data is overwritten with the image data. May be updated. As a result, both basic data and copy data can be maintained. In addition, when there is an error in one of the two data, abnormal data can be overwritten using normal data.

  Next, processing for such an error will be described with reference to FIG. In addition to the flowchart shown in FIG. 3, the GDC 43 performs overwriting processing on the assumption that the rewrite condition is satisfied even when an error occurs in the data of the NAND flash memory 44. When error processing is performed, the NAND flash memory 44 stores one or more copy data for specific specific data among a plurality of image data. In the present embodiment, the data of the background image 42a is used as the specific data. Further, in the present embodiment, the data of the background image 42 a is stored in the NAND flash memory 44 as one specific data and two copy data. As a method for checking an error, for example, a conventional method such as a parity check and a checksum can be adopted.

  In FIG. 4, the specific data is expressed as data 1, and the copy data is expressed as data 11 and data 12. Therefore, data 1, data 11 and data 12 are the same data. At time t1, a circle indicating that all three data are normal and normal for easy understanding is written on the right side of the data name.

  Thereafter, at time t2, an error occurred in data 1, and the data of data 1 was determined to be abnormal. Therefore, in FIG. 4, a cross mark indicating abnormality is written on the right side of the data name for easy understanding. In this case, it is necessary to correct the data 1 having an abnormality in the data.

  Therefore, at time t3, data 1 is corrected by overwriting the storage area of data 1 with data 11 or data 12 which is normal data. As a result, when an error occurs in the data 1, it is overwritten and rewritten to normal data, so that even if an abnormality occurs in the data, it can be recovered early.

  In the example illustrated in FIG. 4, an error has occurred in the data 1 of the specific data. However, the present invention is not limited to the specific data, and the same applies when an error has occurred in the data 11 or data 12 that is copy data. Overwritten with normal data. As a result, the three data can be maintained as normal data. As described above, the GDC 43 periodically checks whether there is an error in the specific data and the copy data. If an error occurs in the specific data or the copy data, an error occurs in the data in which the error has occurred. Overwrite with data that has not been saved. In the example shown in FIG. 4, the NAND flash memory 44 has two copy data. However, the number of copy data is not limited to two, and may be one or three or more. .

  As described above, in the display device 40 of this embodiment, the image data in the NAND flash memory 44 is periodically overwritten by the GDC 43. In the NAND flash memory 44, as time passes, the charge gradually decreases and the data disappears, but the charge can be refreshed by overwriting the data. Therefore, by periodically overwriting the image data, it is possible to suppress the disappearance of the image data over time. As a result, the image data can be held for a long time. The NAND flash memory 44 is suitable for storing image data because it has a large capacity and is inexpensive. Such a NAND flash memory 44 can be suitably used for a vehicle display device.

  In the present embodiment, the NAND flash memory 44 stores one or more copy data for specific specific data among a plurality of image data. The GDC 43 periodically overwrites the specific data with the copy data. As a result, the specific data can be periodically updated with the copy data. As a result, the loss of data over time can be suppressed as described above.

  Further, in the present embodiment, the GDC 43 periodically checks whether there is an error in the specific data and the copy data. If an error has occurred in the specific data or the copy data, the error data is displayed as an error. Overwrite with data that does not occur. As a result, even if an error occurs, data loss can be suppressed.

  In the present embodiment, the overwritten image data is image data displayed on the background of the image displaying the running state. Such data of the background image 42a is data that has a large capacity but does not update frequently and does not change from the time of manufacture. In other words, the data of the background image 42 a is data that is read from the NAND flash memory 44 but is not updated. By storing the background image 42a data in the NAND flash memory 44 and periodically updating the data, the background image 42a can be held in the inexpensive NAND flash memory 44 with a large amount of data.

(Other embodiments)
The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  The structure of the said embodiment is an illustration to the last, Comprising: The scope of the present invention is not limited to the range of these description. The scope of the present invention is indicated by the description of the scope of claims, and further includes meanings equivalent to the description of the scope of claims and all modifications within the scope.

  In the first embodiment, the functions provided by the processors of the control circuit can be provided by hardware and software different from those described above, or a combination thereof. For example, the GDC 43 may be realized by another control circuit. Similarly, the image displayed on the display device 42 may be generated by an image generation circuit provided in these configurations. The NAND flash memory 44 and the NOR flash memory 45 may store data such as programs used for other controls.

  In the first embodiment described above, the copy data is stored in the NAND flash memory 44, but the copy data may not be stored in the NAND flash memory 44. The GDC 43 may be controlled to periodically update data stored in the NAND flash memory 44 including specific data. At this time, as the data to be updated, copy data stored in another memory may be used, or copy data obtained by communication may be used. Further, the GDC 43 may self-update specific data without using copy data, that is, overwrite with self-data.

  In the first embodiment described above, the display 42 is configured to be installed on the instrument panel. However, the display 42 is not limited to such a location, and may be installed in another location such as a center console. The display 42 is not limited to a configuration including a display that displays an image, and may be realized by a head-up display (abbreviated as HUD) that projects and displays driving support information on a front window.

DESCRIPTION OF SYMBOLS 10 ... In-vehicle network 20 ... Perimeter monitoring system 21 ... Front camera unit 22 ... Radar unit 23 ... Perimeter monitoring ECU 30 ... Vehicle control system 31 ... Accelerator position sensor 32 ... Brake pedal force sensor 33 ... Steering angle sensor 34 ... Vehicle control ECU
DESCRIPTION OF SYMBOLS 40 ... Display apparatus (display apparatus for vehicles) 41 ... Meter 42 ... Display (display part) 42a ... Background image 43 ... GDC (control part)
44 ... NAND flash memory 45 ... NOR flash memory 46 ... Meter control circuit 50 ... Communication bus 100 ... Own vehicle

Claims (4)

A vehicle display device (40) that is mounted on a vehicle and displays vehicle information relating to a running state of the vehicle,
A display unit (42) for displaying an image related to the running state;
A NAND flash memory (44) in which a plurality of image data for generating an image to be displayed on the display unit is stored;
A NOR flash memory (45) in which a plurality of image data for generating an image to be displayed on the display unit is stored;
A controller (43) that reads out image data stored in the NAND flash memory and the NOR flash memory and generates an image to be displayed on the display unit,
The storage capacity of the NAND flash memory is greater than the storage capacity of the NOR flash memory,
The vehicle display device, wherein the control unit periodically overwrites image data stored in the NAND flash memory. The NAND flash memory stores one or more copy data for specific specific data among a plurality of image data,
The vehicle display device according to claim 1, wherein the control unit periodically overwrites the specific data with the copy data.   The control unit periodically checks whether there is an error in the specific data and the copy data, and if an error has occurred in the specific data or the copy data, the error data is displayed as an error. The vehicle display device according to claim 2, wherein data is overwritten with data in which no occurrence occurs.   The vehicular display device according to any one of claims 1 to 3, wherein the overwritten image data is image data displayed on a background of an image that displays the traveling state.

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