U.S. patent application number 13/956950 was filed with the patent office on 2014-04-24 for electronic device, communication control method of electronic device, and information terminal device.
This patent application is currently assigned to ALPINE ELECTRONICS, INC.. The applicant listed for this patent is ALPINE ELECTRONICS, INC.. Invention is credited to Takashi Yoshinaga.
Application Number | 20140115202 13/956950 |
Document ID | / |
Family ID | 50486391 |
Filed Date | 2014-04-24 |
United States Patent
Application |
20140115202 |
Kind Code |
A1 |
Yoshinaga; Takashi |
April 24, 2014 |
ELECTRONIC DEVICE, COMMUNICATION CONTROL METHOD OF ELECTRONIC
DEVICE, AND INFORMATION TERMINAL DEVICE
Abstract
An electronic device includes a connection unit that enables a
USB connection to a smartphone, a normal communication mode in
which communication is performed by using a device class prepared
in advance in the smartphone, a request unit that makes a request
for switching to a unique communication mode, a search unit that
searches for a device class usable in the normal communication mode
after the request for switching to the unique communication mode
has been made, a determination unit that determines, on the basis
of a search result, whether or not a disadvantageous change has
occurred in the normal communication mode, and a reset unit that
resets the USB connection when it is determined that a
disadvantageous change has occurred.
Inventors: |
Yoshinaga; Takashi; (Iwaki,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ALPINE ELECTRONICS, INC. |
Tokyo |
|
JP |
|
|
Assignee: |
ALPINE ELECTRONICS, INC.
Tokyo
JP
|
Family ID: |
50486391 |
Appl. No.: |
13/956950 |
Filed: |
August 1, 2013 |
Current U.S.
Class: |
710/62 |
Current CPC
Class: |
G06F 2213/0042 20130101;
G06F 13/426 20130101 |
Class at
Publication: |
710/62 |
International
Class: |
G06F 13/38 20060101
G06F013/38 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 24, 2012 |
JP |
2012-234548 |
Claims
1. An electronic device that is connectable to an information
terminal device, the electronic device comprising: a connection
unit that enables a USB connection to the information terminal
device; a first communication mode in which communication with the
information terminal device is performed by using a device class
prepared in advance in the information terminal device; a request
unit that makes a request to the information terminal device for
switching to a second communication mode which is different from
the first communication mode; a search unit that searches for a
device class usable in the first communication mode after the
request for switching to the second communication mode has been
made; a determination unit that determines, on the basis of a
search result of the search unit, whether or not a disadvantageous
change has occurred in the first communication mode; and a reset
unit that enables a reset of the connection unit when the
determination unit determines that a disadvantageous change has
occurred.
2. The electronic device according to claim 1, further comprising:
an alternative connection information acquisition unit that
acquires alternative connection information regarding a connection
which is able to be used instead of the USB connection; and an
alternative connection unit that enables an alternative connection
to the information terminal device on the basis of the alternative
connection information after the reset unit has performed the
reset.
3. The electronic device according to claim 1, wherein the reset
unit provides a warning requesting a user to unplug and plug the
connection unit.
4. The electronic device according to claim 1, wherein a
determination table indicating a weight of a device class is
prepared in advance and the determination unit determines whether
or not a disadvantageous change has occurred with reference to the
determination table.
5. The electronic device according to claim 1, wherein, when a
device class having been used before switching to the second
communication mode becomes unusable, the determination unit
determines that a disadvantageous change has occurred.
6. The electronic device according to claim 1, wherein, when the
number of device classes usable before switching to the second
communication mode decreases after switching to the second
communication mode, the determination unit determines that a
disadvantageous change has occurred.
7. The electronic device according to claim 1, wherein the first
communication mode reestablishes communication using the first
communication mode after the reset unit has performed the
reset.
8. The electronic device according to claim 1, wherein the
electronic device operates with a mirror link by using the first
communication mode.
9. A communication control method of an electronic device that is
connectable to an information terminal device, the communication
control method comprising the steps of: making a USB connection to
the information terminal device; communicating with the information
terminal device by using a device class prepared in advance in the
information terminal device in a first communication mode; making a
request to the information terminal device for switching to a
second communication mode which is different from the first
communication mode; searching for a device class usable in the
first communication mode after making the request for switching to
the second communication mode; determining, on the basis of a
search result, whether or not a disadvantageous change has occurred
in the first communication mode; and enabling a reset of the USB
connection when it is determined that a disadvantageous change has
occurred.
10. The communication control method according to claim 9, further
comprising the steps of: acquiring alternative connection
information regarding a connection which is able to be used instead
of the USB connection; and making a connection to the information
terminal device by using an alternative connection on the basis of
the alternative connection information after the USB connection has
been reset.
11. The communication control method according to claim 9, wherein
the step of enabling the reset includes providing a warning
requesting a user to unplug and plug the USB connection.
12. The communication control method according to claim 9, wherein,
in the step of determining, a determination table indicating a
weight of a device class is prepared in advance and it is
determined whether or not a disadvantageous change has occurred
with reference to the determination table.
13. An information terminal device that is connectable to an
electronic device, the information terminal device comprising: a
connection unit that enables a USB connection to the electronic
device; a first communication mode in which communication with the
electronic device is performed by using a device class prepared in
advance; a second communication mode that enables communication in
the second communication mode in response to a request from the
electronic device for switching to the second communication mode
which is different from the first communication mode; a providing
unit that provides, to the electronic device, in response to the
request for switching to the second communication mode, alternative
connection information regarding an alternative connection which is
able to be made; and a communication unit that enables
communication using the first communication mode and communication
using an alternative connection unit between the information
terminal device and the electronic device after the connection unit
has been reset.
14. The information terminal device according to claim 13, further
comprising a response application that is activated in response to
the request for switching to the second communication mode, wherein
the response application executes the providing unit and the
communication unit.
15. The information terminal device according to claim 14, wherein
the response application is acquired from an external server in
response to the request for switching to the second communication
mode.
Description
RELATED APPLICATION
[0001] The present application claims priority to Japanese Patent
Application Number 2012-234548, filed Oct. 24, 2012, the entirety
of which is hereby incorporated by reference.
BACKGROUND
[0002] 1. Field of the Invention
[0003] The present invention relates to an electronic device, an
information terminal device, and an electronic system utilizing
them, and more particularly to communication control between the
information terminal device and the electronic device when the
information terminal device is connected.
[0004] 2. Description of the Related Art
[0005] In recent years, with the ever widening use of
multi-function mobile phones typified by smartphones or the like,
the frequency of use of smartphones in vehicles has been
increasing. A smartphone has communication functions, for example,
a third generation (3G) line, a Universal Serial Bus (USB)
connection, and wireless data communications, such as WiFi and
Bluetooth (registered trademark). The use of these functions
enables a voice call and data communication via the Internet or the
like. As well as being used singly, the smartphone may be connected
to an in-vehicle device and thereby may be remotely operated from
the in-vehicle device, and the screen of the smartphone may be
magnified and displayed on the display of the in-vehicle
device.
[0006] The smartphone is connectable to the in-vehicle device by
using a USB connection or other communication devices. USB is used
as a standard interface for connecting between a personal computer
(PC) and a peripheral device. In USB, specification groups called
device classes, which are formed on the basis of the functions of
peripheral devices, are defined. A unified control interface is
prepared for devices made in accordance with each class
specification, and devices complying with the class specification
may be operated by a common device driver called a class driver.
For example, a USB memory belongs to a mass storage class and may
be operated without a driver being newly installed if an OS side
has a class driver corresponding to the mass storage class.
[0007] In recent years, devices, such as MP3 players, implement the
mass storage class, and devices, such as digital cameras, also
implement a still image class, which is used when direct output to
a printer is performed. Japanese Unexamined Patent Application
Publication No. 2006-180356 discloses a USB peripheral device. In
order to prevent a mistake in selecting a device class, when a USB
host is connected, the USB peripheral device displays a desired
device class among a plurality of device classes and prompts a user
to select the displayed device class. In addition, in Japanese
Unexamined Patent Application Publication No. 2008-152404, a user
sets, among device classes supported by a USB host control unit, a
connection-target class whose connection is permitted, and when a
USB device is connected, the connection of only the USB device
whose device class matches the connection-target class set by the
user is permitted. Thus, in the case where an electronic apparatus
and a plurality of device class USB devices are connected and used,
a connection with an appropriate class may be made at all
times.
[0008] In a smartphone, such as an Android terminal, in order to
increase flexibility in a method of communication with peripheral
devices, switching between functions of a USB bus enables switching
to a mode that performs free communication using its own unique
protocol (hereinafter referred to as a unique communication mode)
(for example, Android open accessory protocol). FIG. 1 illustrates
a configuration of layers of an in-vehicle device and a smartphone.
Although both of an in-vehicle device 10 and a smartphone 20 may be
a USB host or a USB peripheral device, the in-vehicle device 10 is
the USB host and the smartphone 20 is the USB peripheral device
here.
[0009] The in-vehicle device 10 includes, in sequence from a high
level, an application layer 11, class driver layers 12, a USB host
driver 13, a Windows Automotive 7 operating system (OS) 14,
hardware 15 and so forth. On the other hand, the smartphone 20
includes, in sequence from a high level, an application layer 21,
class driver layers 22, a USB device driver 23, an Android OS 24,
and hardware 25. In the class driver layers 22 of the smartphone
20, for example, a mass storage class and a communication device
class (NCM) are prepared. In the USB host driver 13 of the
in-vehicle device 10, drivers for operating the mass storage class,
the communication device class (NCM), and the like are
prepared.
[0010] FIG. 2 illustrates an operation sequence performed when a
USB bus is switched from a normal communication mode to a unique
communication mode. When the in-vehicle device 10 and the
smartphone 20 are connected with a USB cable, in the case where the
in-vehicle device 10 operates as a USB host and the smartphone 20
operates as a USB peripheral device, for example, the in-vehicle
device 10 transmits a music play command to the smartphone 20 and
the smartphone 20 transfers audio data to the in-vehicle device 10
in response to this command. The in-vehicle device 10 outputs the
received audio data by using its own amplifier and speaker.
[0011] Now, when the in-vehicle device 10 requests switching to the
unique communication mode in which a unique control command may be
utilized, the smartphone 20 activates a corresponding application,
changes a vender ID (VID)/product ID (PID), and thereby switches
the USB bus from the communication mode utilizing a normal device
class to the unique communication mode. This enables communication
between the in-vehicle device 10 and the smartphone 20 with a free
protocol. However, because this unique communication mode is not a
function implemented in a device class/class driver of an
individual terminal but a special communication mode prepared on
the OS side, a case may arise where a USB interface (device class)
originally included by the terminal may not be able to be used. For
example, a mirror link, and an operation, such as playing of a
music file, may be disabled.
[0012] When the in-vehicle device 10 and the smartphone 20 are
connected to each other, a mirror link has the highest priority.
The mirror link causes the in-vehicle device 10 to serve just like
an input/output device of the smartphone 20. The same picture as
that displayed on the screen of the smartphone 20 may be magnified
and displayed on the display of the in-vehicle device 10, and the
smartphone 20 may be remotely operated by input via a touch panel
or the like of the in-vehicle device 10.
[0013] FIG. 3A illustrates an example where the mirror link becomes
disabled. Before switching to the unique communication mode, a
CDC/NCM class and a CDC network data class used for the mirror link
are allocated as usable USB interfaces. However, when switching to
the unique communication mode is performed, the smartphone 20
erases the CDC/NCM class and the CDC network data class, and
changes the classes serving as the usable USB interfaces to an
Android open accessory class. Thus, the mirror link becomes
disabled.
[0014] FIG. 3B illustrates an example where playing of a music file
becomes disabled. Before switching to the unique communication
mode, the music file of the smartphone 20 may be played by using
the mass storage class as a USB interface. However, when switching
to the unique communication mode is performed, the mass storage
class disappears from the USB interface of the smartphone 20, and a
usable class is changed to the Android open accessory class. Thus,
playing of the music file becomes disabled.
[0015] FIG. 3C illustrates an example where playing of a music file
and the mirror link become disabled. Before switching to the unique
communication mode, the music file may be played by using the mass
storage class as a USB interface, and the mirror link is enabled by
the communication device class (NCM). However, when switching to
the unique communication mode is performed, the mass storage class
and the communication device class (NCM) disappear and are changed
to the Android open accessory class, so that playing of the music
file and the mirror link become disabled.
[0016] Hence, switching from a normal mode utilizing a device
class, which has been prepared in advance and serves as a USB
interface, to a unique communication mode using a unique protocol
disables an existing function. In this case, it is desirable to
evaluate functions of the normal mode and the unique communication
mode and enable selection of communication using a more highly
evaluated mode.
[0017] An object of embodiments of the present invention is to
provide an electronic device that enables selection of either a
normal mode or a unique communication mode, a communication control
method of the electronic device, a communication control program of
the electronic device, an electronic system, and an information
terminal device.
[0018] In addition, an object of embodiments of the present
invention is to provide an electronic device that enables
assignment of a unique communication command to another alternative
connection properly in the case where a normal mode command and the
unique communication command may not be able to coexist in the same
bus, a communication control method of the electronic device, and
an information terminal device.
SUMMARY
[0019] An embodiment of the present invention in one aspect
provides an electronic device that is connectable to an information
terminal device. The electronic device includes a connection unit
that enables a USB connection to the information terminal device, a
first communication mode in which communication with the
information terminal device is performed by using a device class
prepared in advance in the information terminal device, a request
unit that makes a request to the information terminal device for
switching to a second communication mode which is different from
the first communication mode, a search unit that searches for a
device class usable in the first communication mode after the
request for switching to the second communication mode has been
made, a determination unit that determines, on the basis of a
search result of the search unit, whether or not a disadvantageous
change has occurred in the first communication mode, and a reset
unit that enables a reset of the connection unit when the
determination unit determines that a disadvantageous change has
occurred.
[0020] The electronic device preferably further includes an
alternative connection information acquisition unit that acquires
alternative connection information regarding a connection which is
able to be used instead of the USB connection, and an alternative
connection unit that enables an alternative connection to the
information terminal device on the basis of the alternative
connection information after the reset unit has performed the
reset.
[0021] The reset unit preferably includes a warning requesting a
user to unplug and plug the connection unit. Preferably, a
determination table indicating a weight of a device class is
prepared in advance and the determination unit determines whether
or not a disadvantageous change has occurred with reference to the
determination table. When a device class having been used before
switching to the second communication mode becomes unusable, the
determination unit preferably determines that a disadvantageous
change has occurred. When the number of device classes usable
before switching to the second communication mode decreases after
switching to the second communication mode, the determination unit
preferably determines that a disadvantageous change has occurred.
The first communication mode preferably reestablishes communication
using the first communication mode after the reset unit has
performed the reset. The electronic device preferably operates with
a mirror link by using the first communication mode.
[0022] An embodiment of the present invention in another aspect
provides a communication control method for an electronic device
that is connectable to an information terminal device. The
communication control method includes the steps of: making a USB
connection to the information terminal device; communicating with
the information terminal device by using a device class prepared in
advance in the information terminal device in a first communication
mode; making a request to the information terminal device for
switching to a second communication mode which is different from
the first communication mode; searching for a device class usable
in the first communication mode after making the request for
switching to the second communication mode; determining, on the
basis of a search result, whether or not a disadvantageous change
has occurred in the first communication mode; and enabling a reset
of the USB connection when it is determined that a disadvantageous
change has occurred.
[0023] An embodiment of the present invention in another aspect
provides a communication control program executed by an electronic
device that is connectable to an information terminal device. The
communication control program includes the steps of: making a USB
connection to the information terminal device; communicating with
the information terminal device by using a device class prepared in
advance in the information terminal device in a first communication
mode; making a request to the information terminal device for
switching to a second communication mode which is different from
the first communication mode; searching for a device class usable
in the first communication mode after making the request for
switching to the second communication mode; determining, on the
basis of a search result, whether or not a disadvantageous change
has occurred in the first communication mode; and enabling a reset
of the USB connection when it is determined that a disadvantageous
change has occurred.
[0024] An embodiment of the present invention in another aspect
provides an electronic system. The electronic system includes an
electronic device having the above-described features and an
information terminal device that is connected to the electronic
device via the connection unit. In the electronic system, the
information terminal device activates an application in response to
the request for switching to the second communication mode, and the
application notifies the electronic device of the alternative
connection information. The information terminal device preferably
communicates with the electronic device by using the first
communication mode and the alternative connection unit after the
connection unit has been reset.
[0025] An embodiment of the present invention in another aspect
provides an information terminal device that is connectable to an
electronic device. The information terminal device includes a
connection unit that enables a USB connection to the electronic
device, a first communication mode in which communication with the
electronic device is performed by using a device class prepared in
advance, a second communication mode that enables communication in
the second communication mode in response to a request from the
electronic device for switching to the second communication mode
which is different from the first communication mode, a providing
unit that provides, to the electronic device, in response to the
request for switching to the second communication mode, alternative
connection information regarding an alternative connection which is
able to be made, and a communication unit that enables
communication using the first communication mode and communication
using an alternative connection unit between the information
terminal device and the electronic device after the connection unit
has been reset.
[0026] The information terminal device preferably further includes
a response application that is activated in response to the request
for switching to the second communication mode, and the response
application executes the providing unit and the communication unit.
The response application is preferably acquired from an external
server in response to the request for switching to the second
communication mode.
[0027] According to embodiments of the present invention, it is
determined whether or not a disadvantageous change has occurred in
a first communication mode, and when a disadvantageous change has
occurred, a USB connection may be reset, thereby facilitating
selection of the first communication mode. In addition, an
alternative connection may be made, thereby enabling both
communication using the first communication mode and communication
using a second communication mode at the same time. Thus, a
disadvantageous change due to switching to the second communication
mode may be dealt with.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] FIG. 1 illustrates an example of a configuration of layers
of an in-vehicle device and a smartphone;
[0029] FIG. 2 illustrates an operation sequence performed when a
USB bus of the smartphone is switched to a unique communication
mode in the case where the in-vehicle device and the smartphone are
connected with a USB cable;
[0030] FIGS. 3A to 3C illustrate examples of device classes usable
as USB interfaces before and after switching to the unique
communication mode;
[0031] FIG. 4 illustrates the configuration of an in-vehicle
electronic system according to embodiments of the present
invention;
[0032] FIG. 5 is a block diagram illustrating a typical
configuration of an in-vehicle device illustrated in FIG. 4;
[0033] FIG. 6 is a block diagram illustrating a functional
configuration of a communication control program of the in-vehicle
device;
[0034] FIG. 7 is a block diagram illustrating a typical
configuration of a smartphone;
[0035] FIG. 8 is a flowchart illustrating communication control
performed when switching to a unique communication mode is
performed in the in-vehicle electronic system;
[0036] FIGS. 9A to 9C illustrate examples of determination tables
used for determining whether or not a disadvantageous change has
occurred, and FIG. 9D illustrates examples of determination results
based on the determination tables;
[0037] FIG. 10 is a flowchart illustrating an example of the
communication control performed by the in-vehicle electronic system
according to an embodiment;
[0038] FIG. 11 is a flowchart illustrating an example of
communication control performed by the in-vehicle electronic system
when the communication control according to this embodiment is not
used;
[0039] FIG. 12 illustrates changes in device class between before
and after switching to a mirror link and between before and after
switching to a unique communication mode;
[0040] FIG. 13 is a flowchart illustrating communication control
according to a second embodiment of the present invention; and
[0041] FIG. 14 is a flowchart illustrating an operation performed
when the second embodiment of the present invention is not
used.
DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS
[0042] Embodiments for carrying out the present invention will be
described in detail below with reference to the drawings. Here, as
a preferred example, an in-vehicle electronic system including an
in-vehicle device and a smartphone connected to the in-vehicle
device is provided. Note that the present invention is not limited
to such an in-vehicle electronic system that connects between the
in-vehicle device and the smartphone. The in-vehicle device is an
electronic device installed on a vehicle, and functions included
therein are not particularly limited. Examples of the functions may
include an audio and video playing function, a digital terrestrial
television broadcast receiving function, a navigation function, and
a data communication function. A device connected to the in-vehicle
device is not limited to the smartphone, and other terminal devices
may be used. Examples of the device may include a portable personal
computer, a tablet PC, and a portable information processing
apparatus.
Embodiments
[0043] FIG. 4 illustrates an example of an in-vehicle electronic
system 100 according to the embodiments of the present invention.
An in-vehicle device 110 is an electronic device installed on a
vehicle and may have a media playing function, a television
receiving function, and/or a data communication function. A
smartphone 120 is connectable to the in-vehicle device 110 by using
a USB cable or another communication unit. When the smartphone 120
is connected to the in-vehicle device 110 with the USB cable in the
embodiments, an example where the in-vehicle device 110 operates as
a USB host and the smartphone 120 operates as a USB peripheral
device is provided.
[0044] When a USB connection between the in-vehicle device 110 and
the smartphone 120 is made, the in-vehicle device 110 may operate
the smartphone 120 by using a class driver corresponding to a
device class which has been prepared in advance in the smartphone
120 and which serves as a USB interface. For example, the
in-vehicle device 110 and the smartphone 120 constitute a mirror
link and the in-vehicle device 110 thereby may display image data
transferred from the smartphone 120 on its own display and give
input to the smartphone 120 by using an input interface of the
in-vehicle device 110. In addition, an instruction to play a
desired music file stored in the smartphone 120 may be given by a
command from the in-vehicle device 110, and the in-vehicle device
110 may output from its own speaker audio data transferred from the
smartphone 120.
[0045] FIG. 5 is a block diagram illustrating an example of a
typical configuration of the in-vehicle device 110. The in-vehicle
device 110 includes an input unit 200 that receives input from a
user, a USB/data communication unit 210 that enables a
communication connection to an external device, such as the
smartphone 120, a network, and so forth, a display unit 220, an
audio output unit 230 that outputs audio, a media playing unit 240
that plays audio and video data, a control unit 250 that controls
each unit, a program memory 260 that stores program data, and a
data memory 270 that stores various pieces of data.
[0046] Examples of the input received by the input unit 200
preferably include input via a remote control, input via a cursor,
and input to a display via a touch panel. The USB/data
communication unit 210 enables a USB connection to the smartphone
120 and further includes wired and wireless communication units,
such as WiFi, Bluetooth (registered trademark), a local area
network (LAN), and a wireless LAN. As illustrated in FIG. 1, the
program memory 260 stores, for example, Windows Automotive 7 as an
OS for controlling each unit. The program memory 260 also stores a
class driver for operating the smartphone 120 in accordance with a
device class prepared in the smartphone 120 when the smartphone 120
is connected as a USB peripheral device. In addition, in the
embodiments, the program memory 260 stores a communication control
program executed when switching to a unique communication mode is
performed in the smartphone 120. The control unit 250 includes a
processing device, such as a central processing unit (CPU) or a
microcontroller, and loads and executes the program data stored in
the program memory 260 so as to control each unit.
[0047] FIG. 6 is a functional block diagram illustrating the
communication control program according to the embodiments. A
communication control program 270 according to the embodiments
controls communication performed when the in-vehicle device 110
makes a request to the smartphone 120 for switching to the unique
communication mode using a unique protocol in a state where a USB
connection between the in-vehicle device 110 and the smartphone 120
is made. As illustrated in FIG. 6, the communication control
program 270 includes a communication mode switching request unit
272 that requests switching to the unique communication mode, a
device class search unit 274 that searches for a device class
usable after the switching request has been made, a determination
unit 276 that determines, on the basis of the searched device
class, whether or not a disadvantageous change has occurred due to
switching of a communication mode, a reset/warning unit 278 that
performs a bus reset or provides a warning on the basis of a
determination result of the determination unit 276. These
operations will be described later in detail.
[0048] FIG. 7 is a block diagram illustrating an example of a
typical configuration of the smartphone 120. The smartphone 120
includes an input unit 300 that receives input from the user, a
USB/data communication unit 310 that enables a communication
connection to an external device, such as the in-vehicle device
110, a network, and so forth, a display unit 320, an audio output
unit 330 that outputs audio, a media playing unit 340 that plays
audio and video data, a control unit 350 that controls each unit, a
program memory 360 that stores program data, and a data memory 370
that stores various pieces of data. The smartphone 120 further
includes a voice call function, which is not illustrated.
[0049] Examples of the input received by the input unit 300
preferably include input to a display via a touch panel and input
via voice. The USB/data communication unit 310 enables a USB
connection to the in-vehicle device 110 and further includes wired
and wireless communication units, such as WiFi, Bluetooth
(registered trademark), a LAN, and a wireless LAN. As illustrated
in FIG. 1, the program memory 360 stores, for example, Android OS
as an OS for controlling each unit. The program memory 360 also
stores a device class for enabling the smartphone 120 to operate as
a USB peripheral device. The control unit 350 includes a processing
device, such as a central processing unit (CPU) or a
microcontroller, and loads and executes the program data stored in
the program memory 360 so as to control each unit.
[0050] Next, communication control performed by the in-vehicle
electronic system 100 according to a first embodiment of the
present invention will be described. FIG. 8 is a flowchart
illustrating communication control performed when switching to the
unique communication mode is performed in the in-vehicle electronic
system 100. When the smartphone 120 is connected to the in-vehicle
device 110 via the USB cable, the in-vehicle device 110
automatically detects that the smartphone 120 has been connected as
a USB peripheral device and acquires a descriptor defining details
of a USB interface from the smartphone 120. A device class usable
in the smartphone 120 may be identified by using the descriptor.
The in-vehicle device 110 interprets the descriptor, thereby
recognizes a device class required for the operation performed by
the smartphone 120, and loads a class driver corresponding to the
device class. This enables USB communication between the in-vehicle
device 110 and the smartphone 120 by using a communication protocol
of the device class (S101).
[0051] In the in-vehicle device 110, when communication using a
unique control command using a communication protocol other than
that of a device class prepared in the smartphone 120 is performed,
or when a function other than that supported by the device class is
performed, the communication mode switching request unit 272
transmits, to the smartphone 120, a command for requesting
switching the USB communication from a normal mode to the unique
communication mode (S 102).
[0052] The smartphone 120 shifts to the unique communication mode
using a unique protocol in response to the command of the switching
request (S 103). For example, in the case of Android OS, an Android
open accessory protocol is used. When the request for switching of
the communication mode is made, the device class search unit 274
subsequently searches the smartphone 120 for a USB function (S
104). That is, the device class search unit 274 searches for a
device class usable in the smartphone 120 after switching to the
unique communication mode. Through this search, the descriptor is
reacquired from the smartphone 120 and the usable device class is
thereby checked again. This search result is held in a memory or
the like.
[0053] Then, the determination unit 276 determines, on the basis of
the search result, whether or not a disadvantageous change has
occurred due to switching to the unique communication mode (S 105).
In a method of determining whether or not the change is
disadvantageous, a device class usable before switching to the
unique communication mode is compared with a device class usable
after switching to the unique communication mode, and, for example,
when the number of device classes decreases by a given number or
more, it may be determined that a disadvantageous change has
occurred. Alternatively, when a device class having been used
before switching to the unique communication mode is continuously
usable after the switching, it is determined that there is no
disadvantageous change, and when the device class is unusable, it
is determined that there is a disadvantageous change.
[0054] Furthermore, a determination table indicating a weight of a
device class may be prepared in advance and the determination unit
276 may determine whether or not the change is disadvantageous with
reference to this determination table. The determination table is
preferably made with the following elements, a degree of importance
is assigned with respect to each element, and it is evaluated
whether the use of the smartphone 120 in a state where switching to
the unique communication mode has not been performed is useful or
whether the use in a state where the switching has been performed
is useful.
[0055] Functions of In-Vehicle Device
[0056] Readiness or non-readiness for a mirror link
[0057] Capability or incapability of playing music stored in a mass
storage
[0058] Capability or incapability of performing communication by
using another communication bus as an alternative
[0059] User's Preferences
[0060] Whether or not to listen to music stored in a smartphone
[0061] Whether or not to use a mirror link
[0062] Whether or not to use communication uniquely defined by a
manufacturer
[0063] Examples of Determination: A determination table in which
each function is graded by using the determination elements is
prepared in advance, and it is determined whether or not the unique
communication mode is to be used. FIG. 9A illustrates a
determination table A. The determination table A indicates weights
assigned in the case where an in-vehicle device additionally has
another communication bus, such as WiFi or Bluetooth (registered
trademark), and in the case where a mass storage class or a mirror
link is likely to be used for playing of music and so forth. USB
communication makes setting easier than setting in wireless
communication, such as WiFi or Bluetooth (registered trademark),
and enables stable communication. Hence, although a unique
communication mode is graded the low point value "1", the
assignment of not the value "0" but of the value evaluated to some
degree is considered appropriate.
[0064] FIG. 9B illustrates a determination table B. The
determination table B indicates weights assigned in the case where
the in-vehicle device does not additionally have a communication
bus and in the case where the user does not place a high priority
on the mirror link or playing of music using the mass storage class
serving as a USB interface. In this case, a mass storage class and
an NCM class are each graded the point value "1" and the unique
communication mode is graded the high point value "10".
[0065] FIG. 9C illustrates a determination table C. The
determination table C indicates weights assigned in the case where
the in-vehicle device does not additionally have a communication
bus and in the case where the mass storage class or the mirror link
is likely to be used for playing of music and so forth.
[0066] FIG. 9D illustrates results obtained by determining the
examples where playing of a music file or the mirror link becomes
disabled in FIGS. 3A to 3C with the determination tables A to C. A
"normal mode" in FIG. 9D is a communication mode in which a device
class serving as a USB interface is used, that is, in which USB
communication before switching to the unique communication mode is
performed. Because a point value corresponding to the CDC network
data class in FIG. 3A is not prepared in the determination tables A
to C, in the determination using the determination table C, an
evaluation point value is assigned "10" and is equal to the point
value of the unique communication mode. In this case, either the
normal mode or the unique communication mode is decided by using
other determination elements. Thus, the functions of the normal
mode and the unique communication mode are evaluated by using the
determination tables reflecting the functions of the in-vehicle
device and the user's preference, so that it may be determined
whether or not the change is disadvantageous.
[0067] Referring back to the flow in FIG. 8, when the determination
unit 276 determines that there is no disadvantageous change, the
unique communication mode continues. For example, in the unique
communication mode, the smartphone 120 may be caused to perform an
operation, such as e-mail acquisition, by using a unique command.
On the other hand, when the determination unit 276 determines that
there is a disadvantageous change, the reset/warning unit 278
performs a bus reset or displays a warning for the bus reset (S
106).
[0068] The reset/warning unit 278 performs the bus reset of the USB
connection so that the smartphone 120 terminates the unique
communication mode. The bus reset is performed by grounding a D+
terminal and a D- terminal of the USB cable. Alternatively, the
reset/warning unit 278 provides a warning prompting the user to
unplug and plug the USB cable once. When the user plugs the USB
cable in again, the USB connection is reset. The warning may also
indicate, for example, that switching of the communication mode has
disabled an existing function, or that a reset of the USB
connection or initialization is required so as to continuously use
a function having been used until now. Hence, when it is determined
that a disadvantageous change has occurred, the USB communication
with the smartphone 120 may be readily returned from the unique
communication mode to the normal mode (S 107).
[0069] Next, FIG. 10 illustrates a specific operation performed by
the in-vehicle electronic system 100 to which the communication
control according to this embodiment is applied. FIG. 10
illustrates an example of the operation performed in the case where
e-mail acquisition from a smartphone is periodically set while a
mass storage class is in use and music is being played. The user
inputs an instruction to request the in-vehicle device 110 to play
a music file stored in the smartphone 120. In the case of a mirror
link, this instruction is transferred to the smartphone 120 via the
in-vehicle device 110. The in-vehicle device 110 receives audio
data of the music file from the smartphone 120 by using the mass
storage class and plays the music file (S201). When e-mail
acquisition is performed while the music file is being played, the
in-vehicle device 110 makes a request to the smartphone 120 for
switching to the unique communication mode because a mail
acquisition operation is performed by using a unique control
command. Subsequently, the communication control sequence
illustrated in FIG. 8 is performed between the in-vehicle device
110 and the smartphone 120, and it is determined, for example,
whether or not a disadvantageous change has occurred (S202).
[0070] Here, because the function currently in use is lost, it is
determined that a disadvantageous change has occurred. As a result,
the in-vehicle device 110 performs a bus reset and terminates the
unique communication mode between it and the smartphone 120. Thus,
the USB communication between the in-vehicle device 110 and
smartphone 120 is returned to the normal mode. This processing is
performed with the operation of playing the music file being
performed in the background. In the in-vehicle device 110, when the
operation reaches the end of the music file being played or a
certain point before the end (S203), the in-vehicle device 110
successfully acquires a next music file from the smartphone 120 by
using the mass storage class and subsequently plays the next music
file (S204).
[0071] FIG. 11 illustrates a flow performed in the case where the
communication control according to this embodiment is not performed
in the example in FIG. 10. When a request for switching to the
unique communication mode is made so as to periodically acquire
mail while music is being played, the smartphone 120 performs
switching to the unique communication mode. As a result, the mass
storage class disappears and becomes unusable (S210). Then, in the
unique communication mode, mail is acquired from the smartphone 120
and the mail is displayed on the display of the in-vehicle device
110 (S211). In the in-vehicle device 110, when the operation
reaches the end of the music file being played or a certain point
before the end (S212), the in-vehicle device 110 attempts to
acquire a next music file from the smartphone 120. However, an
acquisition error occurs because the mass storage class has
disappeared or has been unusable, so that music may not be able to
be played. If the user prefers e-mail acquisition to playing of
music, the continuation of such a unique communication mode
presents no problem. However, if the user places a higher priority
on playing of music than on e-mail acquisition, the continuation
makes the user feel uncomfortable.
[0072] In this way, in this embodiment, when the in-vehicle device
110 causes the smartphone 120 to perform switching of the
communication mode, the in-vehicle device 110 stores functions
usable before and after the switching and determines whether or not
the smartphone 120 is to be used in the unique communication mode.
When the in-vehicle device 110 determines that the smartphone 120
is to be used in the normal mode, the in-vehicle device 110 resets
the bus or displays a dialog box in which the user is prompted to
unplug and plug a connector. In the determination whether or not
the smartphone 120 is to be used in the unique communication mode,
for example, evaluation is made by grading the functions before and
after the switching on the basis of the functions of the in-vehicle
device 110 and user's settings and preferences. By using such a
configuration, communication with a smartphone in a mode having
superiority over other modes may be selected for a terminal, such
as an Android terminal, having its own unique communication mode
switching function in accordance with a function of an in-vehicle
device and user's preferences.
[0073] Next, a second embodiment of the present invention will be
described. In a smartphone, such as an Android terminal,
communication, such as communication using a mirror link to which
Virtual Network Computing (VNC) is applied in order to interact
with an in-vehicle device, may be performed. However, because an
operating system defined in the smartphone is basically used, the
smartphone has not been optimized for control from the in-vehicle
device. Thus, in order to perform a unique operation, a unique
communication mode using a unique control command is effective.
[0074] Although a mirror link is usable in communication using
WiFi, Bluetooth (registered trademark), or USB, selection of the
bus supported by the mirror link is left to a vendor, and the case
where communication using USB is offered is likely to increase in
view of communication speed or stability. At this time, if a
control command may be transmitted and received by using the same
bus, a user's time and effort may be reduced. However, when
switching to the unique communication mode is performed, there is
the case where the mirror link and the control command are not
compatible with each other in the same bus, so that the mirror link
having a high priority may become disabled (see the example in FIG.
3A).
[0075] FIG. 12 illustrates an example of SAMSUNG GALAXY SIII. In
the specification of this smartphone, classes for a mirror link do
not appear in a steady state; whereas, when software for the mirror
link is activated, classes appearing in the steady state disappear
from sight and the classes (a CDC/NCM class and a CDC network data
class) for the mirror link are activated. In this state, when
switching to a unique communication mode is performed so as to
perform unique communication, the classes for the mirror link
disappear. That is, there is a similar problem to that in the
example illustrated in FIG. 3A where the mirror link becomes
disabled.
[0076] In the second embodiment, in the case where the mirror link
is usable even if a communication mode is changed, USB
communication is continuously performed, and in the case where the
mirror link is unusable, a connection to an alternative bus is
made. FIG. 13 is a flowchart illustrating communication control
according to the second embodiment. A USB connection between the
in-vehicle device 110 and the smartphone 120 is made and the mirror
link is in a usable state (S301). Here, the communication mode
switching request unit 272 of the in-vehicle device 110 makes a
request to the smartphone 120 for switching a USB communication
mode to the unique communication mode (S302). The smartphone 120
performs switching to the unique communication mode in response to
the switching request and activates a response application (S303).
The response application is activated automatically if it has been
installed in the smartphone 120. If the response application has
not been installed, the smartphone 120 accesses an information
distribution server and downloads the response application from the
server and activates it. The response application has capabilities
of providing an alternative bus and providing information required
for connection. The response application communicates with and
responds to the in-vehicle device 110 when switching to the unique
communication mode is performed.
[0077] Next, after the request for switching to the unique
communication mode has been made, the device class search unit 274
checks whether or not the mirror link is in a usable state (S304).
This is checked by acquiring a descriptor as in the first
embodiment. Subsequently, the determination unit 276 determines
whether or not the mirror link is usable (S305). When the mirror
link is usable, the USB communication using a control command is
continuously performed by using the same bus and this sequence
ends.
[0078] On the other hand, when it is determined that the mirror
link is not usable, that is, when a disadvantageous change has
occurred, the in-vehicle device 110 makes an inquiry to the
response application as to whether or not there is an alternative
bus that enables the communication using the control command, and
acquires alternative bus information required for connection of the
alternative bus (S306). Examples of the alternative bus information
include Bluetooth profiles, a PIN code, and an IP address/port
number in the case of a TCP/IP socket. The in-vehicle device 110
responds to the response application to designate the alternative
bus (for example, WiFi or Bluetooth (registered trademark)). The
in-vehicle device 110 determines that the communication using the
alternative bus may be performed, and resets the USB bus for
recovery (S307). Alternatively, the in-vehicle device 110 requests
the user to unplug and plug a USB cable once by displaying a
warning. Then, the in-vehicle device 110 requests activation of the
mirror link (S308) and the response application puts the mirror
link into a usable state again in response to the request (S309).
Subsequently, the response application opens a line of the
alternative bus; whereas, the in-vehicle device 110 performs
communication using the unique control command by using Bluetooth
(registered trademark), WiFi, or the like on the basis of the
alternative bus information (S310).
[0079] FIG. 14 illustrates an example of communication control
performed when the second embodiment of the present invention is
not used. In the case where the mirror link is in a usable state
and the in-vehicle device 110 is connected to the smartphone 120
(S401), when the in-vehicle device 110 requests switching of a USB
communication mode for unique communication control (S402), the
smartphone 120 performs switching to the unique communication mode
and activates the response application (S403). Thus, the unique
communication mode becomes usable; however, because an alternative
bus is not prepared, the mirror link is put into an unusable state
(S404).
[0080] In this way, in the second embodiment, the in-vehicle device
110 makes a request for switching to the unique communication mode
to the smartphone 120 in which the mirror link is ready, and the
smartphone 120 activates, in response to the switching request, a
response application for an in-vehicle device. The response
application communicates with and responds to the in-vehicle device
110. When the mirror link is continuously usable after switching as
well, communication using a control command is continuously
performed by using the same bus, and when the mirror link becomes
unusable, the in-vehicle device 110 makes an inquiry to the
response application about an alternative bus that enables
communication using the control command. The response application
provides the alternative bus and then notifies bus information
required for connection. The in-vehicle device 110 responds to the
response application to designate the alternative bus to be used.
Then, the in-vehicle device 110, for example, resets the USB bus
and/or requests the user to physically unplug and plug the USB bus
once by displaying a warning for the sake of recovery of the mirror
link, thereby returning the mirror link to a usable state.
Subsequently, because a communication path for the control command
is established in the designated bus, in the case where the unique
control command and the mirror link may not be able to coexist in
the same bus, the in-vehicle device 110 assigns the unique command
to another usable bus properly, thereby enabling the coexistence
with the mirror link.
[0081] In the second embodiment, the example where the mirror link
is used as a device class serving as a USB interface is provided.
However, the second embodiment may be applied to USB communication
using a device class other than the mirror link. In this case as
well, in order to cause communication using a unique control
command to coexist with the communication using the device class,
assignment to an alternative bus may be performed.
[0082] While there has been illustrated and described what is at
present contemplated to be preferred embodiments of the present
invention, it will be understood by those skilled in the art that
various changes and modifications may be made, and equivalents may
be substituted for elements thereof without departing from the true
scope of the invention. In addition, many modifications may be made
to adapt a particular situation to the teachings of the invention
without departing from the central scope thereof. Therefore, it is
intended that this invention not be limited to the particular
embodiments disclosed, but that the invention will include all
embodiments falling within the scope of the appended claims.
* * * * *