This invention relates to a transmitting device, a
transmitting method, a receiving device, a receiving
10 method, a transmitting/receiving system, and a cable, and
more particularly, to a transmitting device or the like
that transmits digital signals such as video signals via
a transmission path with differential signals.
15 BACKGROUND ART
[0002]
In recent years, HDMI (High Definition Multimedia
Interface) has been widely used as digital interfaces
that connect CE (Consumer Electronics) devices, and has
20 become a de-facto standard. For example, Non-Patent
Document 1 describes the HDMI standard. According to the
HDMI standard, three data differential line pairs (TMDS
Channels 0/1/2) are used, and video, audio, and control
signals are transmitted as digital signals.
25
CITATION LIST
NON-PATENT DOCUMENT
[0003]
Non-Patent Document 1: High-Definition Multimedia
30 Interface Specification Version 1.4, February 2 2010
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SUMMARY OF THE INVENTION
PROBLEMS TO BE SOLVED BY THE INVENTION
[0004]
At present, the value defined as the digital signal
5 transmission speed by the HDMI standard is approximately
10.2 Gbps at the highest. To cope with high-quality 3D
(3-dimension) video signals and video signals of the
future 4k2k (QFHD) and high-resolution content, the
transmission speed in the future is expected to be
10 increased to 15 Gbps or 20 Gbps, which is higher than the
highest value defined by the current HDMI standard.
[0005]
There are two possible approaches to the higherspeed
HDMI. One is a technique by which the current
15 three data differential line pairs are used as they are,
and the clock speed at which data is transmitted is
increased so as to increase the transmission rate
accordingly. By this technique, however, extending the
transmission band only by increasing the clock speed is
20 difficult due to the physical limit on the use of copper
cable differential pairs. Even if this technique can be
used, it is easy to assume that the transmission distance
will become extremely short. That is, limitations will
be put on the lengths of HDMI cables connecting devices.
25 [0006]
The other means to solve the problem relevant to
the present invention is to increase the number of data
differential line pairs, which is currently three, to
four or larger. The data rate can be increased by the
30 amount equivalent to the increase in the number of data
transmitting lanes. By this technique of increasing the
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data differential line pairs, however, the compatibility
with the current HDMI becomes an issue. Specifically, if
the number of pins in each connector, which is
conventionally 19, is simply increased by the number of
5 data differential line pairs, the compatibility with
conventional devices will be lost, and misunderstandings
and confusion will be caused among users. Therefore,
this technique is not preferable.
[0007]
10 A solution to this is maintaining the compatibility
of each connector (plug or receptacle). That is, the
wiring needs to be designed so that any functional
defects will not be caused in the cables while the
conventional 19-pin connectors are used as they are.
• 15 [0008]
An object of this invention is to provide a novel
digital interface (new HDMI) that has a high degree of
compatibility with the current HDMI, and can transmit
signals at a higher data rate than the current HDMI.
20 Another object of this invention is to provide a
transmitting device and a receiving device that have the
functions of the current HDMI and the new HDMI, and
perform excellent signal transmission.
25 SOLUTIONS TO PROBLEMS
[0009]
A concept of this invention lies in a transmitting
device that includes: a digital signal transmitting unit
that transmits a digital signal to an external device via
30 a transmission path with a differential signal, and has a
first operating mode involving a first number of channels
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for the differential signal and a second operating mode
involving a second number of channels for the
differential signal, the second number being larger than
the first number; an operating mode determining unit that
5 determines whether the external device and the
transmission path are compatible with the second
operating mode; and an operation control unit that
controls the operation of the digital signal transmitting
unit, based on the determination performed by the
10 operating mode determining unit.
[0010]
In this invention, the digital signal transmitting
unit transmits a digital signal to the external device (a
receiving device) via the transmission path with a
15 differential signal. The digital signal transmitting
unit has the first operating mode and the second
operating mode, and selectively uses one of the modes.
The number of differential signal channels is the first
number in the first operating mode, and is the second
20 number, which is larger than the first number, in the
second operating mode. For example, the first operating
mode is a current HDMI operating mode, and the first
number is three. The second operating mode is a new HDMI
operating mode, and the second number is six, which is
25 larger than three.
[0011]
For example, the transmission path is a cable, and
a receptacle having pins is provided for connecting a
plug of this cable thereto. The digital signal
30 transmitting unit selects a first pin assignment in the
first operating mode, and selects a second pin assignment
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in the second operating mode. The second pin assignment
is different from the first pin assignment. In the
second pin assignment, a terminal that is used as a
shield terminal corresponding to a signal terminal of a
5 differential signal for a digital signal and/or a clock
signal in the first pin assignment is used as a signal
terminal of a differential signal for a digital signal,
for example. Alternatively, in the second pin assignment,
a signal terminal of a differential signal for a clock
10 signal in the first pin assignment is used as a signal
terminal of a differential signal for a digital signal,
for example.
[0012]
The operating mode determining unit determines
15 whether the external device and the transmission path are
compatible with the second operating mode. For example,
the operating mode determining unit determines whether
the external device is compatible with the second
operating mode, based on the capability information about
20 the external device. The capability information is read
from the external device via the transmission path.
Alternatively, the operating mode determining unit
determines whether the external device is compatible with
the second operating mode, by performing communication
25 with the external device via the transmission path, for
example.
[0013]
For example, the operating mode determining unit
determines whether the transmission path is compatible
30 with the second operating mode, by using the information
providing function of the transmission path compatible
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with the second operating mode. The information
providing function of the transmission path compatible
with the second operating mode is a function to report to
the external device that the transmission path is
5 compatible with the second operating mode, for example.
The external device has a function to add the information
reported from the transmission path to the capability
information thereof. The operating mode determining unit
determines whether the transmission path is compatible
10 with the second operating mode, based on the capability
information read from the external device via the
transmission path.
[0014]
Alternatively, the information providing function
15 of the transmission path compatible with the second
operating mode is a function to rewrite the information
indicating whether the transmission path is compatible
with the second operating mode so as to indicate that
compatibility with the second operating mode, for example.
20 The information is contained in the capability
information read from the external device. The operating
mode determining unit determines whether the transmission
path is compatible with the second operating mode, based
on the capability information read from the external
25 device via the transmission path.
[0015]
Alternatively, the information providing function
of the transmission path compatible with the second
operating mode is a function to provide information
30 indicating that the transmission path is compatible with
the second operating mode through near field
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communication, for example. The operating mode
determining unit determines whether the transmission path
is compatible with the second operating mode, based on
whether the information indicating that the transmission
5 path is compatible with the second operating mode is
provided from the transmission path through the near
field communication.
[0016]
The operating mode determining unit transmits a
10 differential signal for a predetermined digital signal to
the external device, by using a pair of signal lines in
the transmission path, for example. The pair of signal
lines does not form a differential signal transmission
path in the first operating mode, but do form a
15 differential signal transmission path in the second
operating mode. Based on a signal sent from the external
device, the operating mode determining unit performs the
determination. The signal sent from the external device
is a signal that indicates whether a received digital
20 signal obtained through the predetermined differential
signal received by the external device is correct, for
example. Alternatively, the signal sent from the
external device is a received digital signal obtained
through the predetermined differential signal received by
25 the external device, for example.
[0017]
As described above, in this invention, the digital
signal transmitting unit has the first operating mode in
which the number of differential signal channels is the
30 first number, and the second operating mode in which the
number of differential signal channels is the second
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number, which is larger than the first number. As the
second operating mode (a new HDMI standard) is used,
signal transmission can be performed at a high data rate.
Also, when the external device, the transmission path, or
5 the like is not compatible with the second operating mode,
the first operating mode (the current HDMI standard) is
used, to secure backward compatibility.
[0018]
In this invention, the transmission device further
10 includes an information transmitting unit that transmits
the result of the determination performed by the
operating mode determining unit to the external device
via the transmission path, for example. In this case,
when the external device includes a digital signal
15 receiving unit that has the first operating mode in which
the number of differential signal channels is the first
number and the second operating mode in which the number
of differential signal channels is the second number,
which is larger than the first number, operations of the
20 digital signal receiving unit can be controlled based on
the above mentioned determination result, for example.
[0019]
In this invention, the shape of the receptacle may
match the shape of a plug of a cable compatible with the
25 second operating mode, and may include the shape of a
plug of a cable compatible with the first operating mode.
In this case, the plug of the cable compatible with the
second operating mode can be connected to the receptacle,
and the plug of the cable compatible with the first
30 operating mode can also be connected to the receptacle.
In this manner, backward compatibility is secured in
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terms of cable connections. In this case, the shape of
the receptacle of a transmitting device including a
digital signal transmitting unit compatible only with the
first operating mode matches the shape of the plug of the
5 cable compatible with the first operating mode.
Therefore, the plug of the cable compatible with the
second operating mode cannot be connected to this
receptacle.
[0020]
10 In this invention, the transmitting device may
further include a display control unit that controls
display on a display unit for providing control
information about the operation control unit to a user.
In this case, the user can easily recognize how the
15 digital signal transmitting unit is being controlled.
For example, the user can easily recognize whether the
digital signal transmitting unit is in the first
operating mode or in the second operating mode.
[0021]
20 In this invention, when the operating mode
determining unit has determined that the external device
and the transmission path are compatible with the second
operating mode, the display control unit may perform
control to display a user interface screen on the display
25 unit. The user interface screen is for allowing a user
to select the first operating mode or the second
operating mode for the digital signal transmitting unit.
In this case, the^ user can arbitrarily set an operating
mode for the digital signal transmitting unit, based on
30 the user interface screen.
[0022]
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Another concept of this invention lies in a
receiving device that includes: a digital signal
receiving unit that receives a digital signal from an
external device via a transmission path with a
5 differential signal, and has a first operating mode
involving a first number of channels for the differential
signal and a second operating mode involving a second
number of channels for the differential signal, the
second number being larger than the first number; an
10 information receiving unit that receives, from the
external device, operating mode information indicating
which one of the first operating mode and the second
operating mode is to be selected; and an operation
control unit that controls the operation of the digital
15 signal receiving unit, based on the operating mode
information received by the information receiving unit.
[0023]
In this invention, the digital signal receiving
unit receives a digital signal from the external device
20 (the transmitting device) via the transmission path with
a differential signal. The digital signal receiving unit
has the first operating mode and the second operating
mode, and selectively uses one of the modes. The number
of differential signal channels is the first number in
25 the first operating mode, and is the second number, which
is larger than the first number, in the second operating
mode. For example, the first operating mode is a current
HDMI operating mode, and the first number is three. The
second operating mode is a new HDMI operating mode, and
30 the second number is six, which is larger than three.
[0024]
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The information receiving unit receives, from the
external device, the operating mode information
indicating which one of the first operating mode and the
second operating mode is to be selected. Based on the
5 operating mode information received by the information
receiving unit, the operation control unit controls the
operation of the digital signal receiving unit. In this
case, the operating mode of the digital signal receiving
unit can be easily made the same as the operating mode of
10 the digital signal transmitting unit of the external
device, and digital signals can be received from the
external device in an excellent manner.
[0025]
Another concept of this invention lies in a
15 transmitting/receiving system formed by connecting a
transmitting device and a receiving device via a
transmission path. The transmitting device includes: a
digital signal transmitting unit that transmits a digital
signal to the receiving device via the transmission path
20 with a differential signal, and has a first operating
mode involving a first number of channels for the
differential signal and a second operating mode involving
a second number of channels for the differential signal,
the second number being larger than the first number; an
2 5 operating mode determining unit that determines whether
the receiving device and the transmission path are
compatible with the second operating mode; a transmitting
operation control unit that controls the operation of the
digital signal transmitting unit, based on the
30 determination performed by the operating mode determining
unit; and an information transmitting unit that transmits
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operating mode information about the digital signal
transmitting unit to the receiving device via the
transmission path. The receiving device includes: a
digital signal receiving unit that receives the digital
5 signal from the transmitting device via the transmission
path with the differential signal, and has the first
operating mode involving the first number of channels for
the differential signal and the second operating mode
involving the second number of channels for the
10 differential signal; an information receiving unit that
receives the operating mode information from the
transmitting device via the transmission path; and a
receiving operation control unit that controls the
operation of the digital signal receiving unit, based on
15 the operating mode information received by the
information receiving unit.
[0026]
Yet another concept of this invention lies in a
cable that transmits a digital signal from a transmitting
20 device to a receiving device with a differential signal
having a predetermined number of channels, and includes
an information providing function unit that provides
information indicating the signal transmission capability
of the cable to the transmitting device or the receiving
25 device.
[0027]
For example, the information providing function
unit provides the information indicating the signal
transmission capability of the cable to the receiving
30 device or the transmitting device via the cable, in
response to a request from the receiving device or the
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transmitting device. Also, the information providing
function unit rewrites part of capability information the
transmitting device reads from the receiving device via
the cable, for example. Also, the information providing
5 function unit provides the information indicating the
signal transmission capability of the cable to the
transmitting device or the receiving device through near
field communication, for example.
10 EFFECTS OF THE INVENTION
[0028]
According to this invention, signal transmission
can be performed at a high data rate while backward
compatibility is secured.
15
BRIEF DESCRIPTION OF DRAWINGS
[0029]
Fig. 1 is a block diagram showing an exemplary
structure of an AV system as an embodiment of this
20 invention.
Fig. 2 is a diagram showing example combinations of
a source device, an HDMI cable, and a sink device.
. Fig. 3 is a diagram showing exemplary structures of
the data transmitting unit of a source device and the
25 data receiving unit of a sink device (in a current HDMI
operating mode).
Fig. 4 is a diagram showing exemplary structures of
the data transmitting unit of a source device and the
data receiving unit of a sink device (in a new HDMI
30 operating mode).
Fig. 5 is a diagram showing an exemplary structure
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of TMDS transmission data.
Fig. 6 is a diagram showing a comparison between a
pin assignment of current HDMI (Type A) and a pin
assignment of new HDMI.
5 Fig. 7 is a diagram showing the pin layouts in the
receptacles of source devices and sink devices of the
current HDMI and the new HDMI.
Fig. 8 is a diagram showing an exemplary structure
of a current HDMI cable.
10 Fig. 9 is a diagram showing an exemplary structure
of a new HDMI cable.
Fig. 10 is a diagram showing another exemplary
structure of a new HDMI cable.
Fig. 11 is a flowchart showing an example of
15 procedures in an operating mode controlling operation of
the control unit of a source device.
Fig. 12 is a diagram showing examples of UI screens
displayed on a display unit (a display) under the control
of the control unit of a source device.
20 Fig. 13 is a flowchart showing another example of
procedures in an operating mode controlling operation of
the control unit of a source device.
Fig. 14 is a diagram showing an example of flag
information newly defined in EDID.
25 Fig. 15 is a diagram for explaining a method
implemented by the control unit to determine whether the
cable is compatible with the new HDMI, and is a diagram
showing that an LSI is contained in a plug of the new
HDMI cable.
30 Fig. 16 is a diagram for explaining a method
implemented by the control unit to determine whether the
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cable is compatible with the new HDMI, and is a diagram
showing an example of an EDID data rewrite circuit of an
LSI in the new HDMI cable.
Fig. 17 is a diagram for explaining a method
5 implemented by the control unit to determine whether the
cable is compatible with the new HDMI, and is a diagram
showing that a RF tag chip (LSI) is contained in a plug
of the new HDMI cable.
Fig. 18 is a diagram for explaining a method
10 implemented by the control unit to determine whether the
cable is compatible with the new HDMI, and is a diagram
for explaining that the electrical properties of the
cable are measured to determine whether the cable is
compatible with the new HDMI.
15 Fig. 19 is a diagram for explaining that the
electrical properties of the cable are measured to
determine whether the cable is compatible with the new
HDMI.
Fig. 20 is a diagram for explaining other examples
20 of the shapes of a plug of a new HDMI cable and a
receptacle.
Fig. 21 is a perspective view of a plug of a
current HDMI cable and a plug of a new HDMI cable.
25 MODES FOR CARRYING OUT THE INVENTION
[0030]
The following is a description of modes for
carrying out the invention (hereinafter referred to as
"embodiments"). Explanation will be made in the
30 following order.
1. Embodiments
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2. Modifications
[0031]
<1. Embodiments>
[Exemplary structure of an AV system]
5 Fig. 1 shows an exemplary structure of an AV (Audio
and Visual) system 100 as an embodiment. This AV system
100 is formed by connecting a source device 110 and a
sink device 120. The source device 110 is an AV source
such as a game machine, a disk player, a set-top box, a
10 digital camera, or a portable telephone. The sink device
120 is a television receiver or a projector, for example.
[0032]
The source device 110 and the sink device 120 are
connected via a cable 200. In the source device 110, a
15 receptacle 111 that has a data transmitting unit 112
connected thereto and forms a connector is provided. In
the sink device 120, a receptacle 121 that has a data
receiving unit 122 connected thereto and forms a
connector is provided. A plug 201 that forms a connector
20 is provided at one end of the cable 200, and a plug 202
that forms a connector is provided at the other end. The
plug 201 at the one end of the cable 200 is connected to
the receptacle 111 of the source device 110, and the plug
202 at the other end of the cable 200 is connected to the
25 receptacle 121 of the sink device 120.
[0033]
The source device 110 includes a control unit 113.
The control unit 113 controls the entire source device
110. In this embodiment, the data transmitting unit 112
30 of the source device 110 is compatible with both current
HDMI and new HDMI. In a case where the control unit 113
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determines that the cable 200 is compatible with the new
HDMI, and the sink device 120 is compatible with the new
HDMI, the control unit 113 controls the data transmitting
unit 112 to operate in a new HDMI operating mode. In a
5 case where the control unit 113 determines that at least
the sink device 120 is compatible only with the current
HDMI, or at least the cable 200 is compatible with the
current HDMI, the control unit 113 controls the data
transmitting unit 112 to operate in a current HDMI
10 operating mode.
[0034]
The sink device 120 includes a control unit 123.
The control unit 123 controls the entire sink device 120.
In this embodiment, the data receiving unit 122 of the
15 sink device 120 is compatible only with the current HDMI
or is compatible with both the current HDMI and the new
HDMI. In a case where the data receiving unit 122 is
compatible with both the current HDMI and the new HDMI,
the control unit 123 controls the data receiving unit 122
20 to operate in the same operating mode as the data
transmitting unit 112 of the source device 110. In this
case, based on an operating mode determination result
that is sent from the source device 110 through a line
such as a CEC line, the control unit 123 controls the
25 operating mode of the data receiving unit 122. The cable
200 is compatible with the current HDMI or the new HDMI.
[0035]
In the AV system 100 shown in Fig. 1, when the
cable 200 is compatible with the new HDMI while the sink
30 device 120 is compatible with both the current HDMI and
the new HDMI as shown in Fig. 2(a), data transmission is
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performed through the new HDMI. At this point, the data
transmitting unit 112 of the source device 110 and the
data receiving unit 122 of the sink device 120 are
controlled to operate in the new HDMI operating mode.
5 [0036]
In the AV system 100 shown in Fig. 1, when at least
the cable 200 is compatible with the current HDMI or when
the sink device 120 is compatible only with the current
HDMI as shown in Figs. 2(b) through 2(d), data
10 transmission is performed through the current HDMI. At
this point, the data transmitting unit 112 of the source
device 110 is controlled to operate in the current HDMI
operating mode. The data receiving unit 122 of the sink
device 12 0 compatible with both the current HDMI and the
15 new HDMI is controlled to operate in the current HDMI
operating mode. In the case illustrated in Fig. 2(b),
when the cable 200 can transmit data through the new HDMI
as the data transfer rate is lowered, data transmission
might be performed in the new HDMI operating mode.
20 [0037]
[Exemplary structures of the data transmitting unit and
the data receiving unit]
Figs. 3 and 4 show exemplary structures of the data
transmitting unit 112 of the source device 110 and the
25 data receiving unit 122 of the sink device 120 in the AV
system 100 shown in Fig. 1. In an effective image period
(also called an "active video period"), the data
transmitting unit 112 unidirectionally transmits
differential signals corresponding to uncompressed video
30 data of one screen, to the data receiving unit 122
through more than one channel.
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[0038]
Here, an effective image period is a period from a
vertical synchronization signal to the next vertical
synchronization signal minus the horizontal blanking
5 period and the vertical blanking period. In the
horizontal blanking period or the vertical blanking
period, the data transmitting unit 112 also
unidirectionally transmits at least differential signals
corresponding to the audio data, control data, and other
10 auxiliary data accompanying the video data, to the data
receiving unit 122 through more than one channel.
[0039]
In the active video period, the data receiving unit
112 receives the differential signals corresponding to
15 the video data unidirectionally transmitted from the data
transmitting unit 122 through more than one channel. In
the horizontal blanking period or the vertical blanking
period, the data receiving unit 122 also receives the
differential signals corresponding to the audio data and
20 control data unidirectionally transmitted from the data
transmitting unit 112 through more than one channel.
[0040]
The transmission channels of the HDMI system formed
with the data transmitting unit 112 and the data
25 receiving unit 122 include the following channels. First,
there are differential signal channels (TMDS channels and
a TMDS clock channel) as the transmission channels. The
number of differential signal channels for transmitting
digital signals such as video data is three in the
30 current HDMI, but is six in the new HDMI.
[0041]
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The differential signal channels in the current
HDMI are now described. As shown in Fig. 3, there are
three TMDS channels #0 through #2 as the transmission
channels for serially transmitting video data and audio
5 data unidirectionally from the data transmitting unit 112
to the data receiving unit 122 in synchronization with a
pixel clock. There is a TMDS clock channel as the
transmission channel for transmitting a TMDS clock.
[0042]
10 An HDMI transmitter 81 of the data transmitting
unit 112 converts uncompressed video data to
corresponding differential signals, for example, and
serially transmits, through the three TMDS channels #0,
#1, and #2, the differential signals unidirectionally to
15 the data receiving unit 122 that is connected via the
cable 200. The HDMI transmitter 81 also converts the
audio data, necessary control data, and other auxiliary
data accompanying the uncompressed video data to
corresponding differential signals, and serially
20 transmits, through the three TMDS channels #0, #1, and #2,
the differential signals unidirectionally to the data
receiving unit 122.
[0043]
Further, the HDMI transmitter 81 transmits a TMDS
25 clock synchronized with the video data, which are
transmitted through the three TMDS channels #0, #1, and
#2, to the data receiving unit 122 through the TMDS clock
channel. Here, in one TMDS channel #i (i = 0, 1, 2), 10-
bit video data is transmitted in one clock of the TMDS
30 clock.
[0044]
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An HDMI receiver 82 of the data receiving unit 122
receives the differential signals corresponding to the
video data and the differential signals corresponding to
the audio data and control data, which are transmitted
5 unidirectionally from the data transmitting unit 112,
through the TMDS channels #0, #1, and #2. In this case,
the reception is performed in synchronization with the
pixel clock (the TMDS clock) transmitted from the data
transmitting unit 112 through the TMDS clock channel.
10 [0045]
Next, the differential signal channels in the new
HDMI are described. As shown in Fig. 4, there are six
TMDS channels #0 through #5 as the transmission channels
for serially transmitting video data and audio data
15 unidirectionally from the data transmitting unit 112 to
the data receiving unit 122 in synchronization with a
pixel clock. In this new HDMI, a self-clock technique by
which the transmission of the TMDS clock is skipped, and
the clock is reproduced from received data at the
20 receiving end is used.
[0046]
The HDMI transmitter 81 of the data transmitting
unit 112 converts uncompressed video data to
corresponding differential signals, for example, and
25 serially transmits, through the six TMDS channels #0
through #5, the differential signals unidirectionally to
the data receiving unit 122 that is connected via the
cable 200. The HDMI transmitter 81 also converts the
audio data, necessary control data, and other auxiliary
30 data accompanying the uncompressed video data to
corresponding differential signals, and serially
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transmits, through the six TMDS channels #0 through #5,
the differential signals unidirectionally to the data
receiving unit 122.
[0047]
5 The HDMI receiver 82 of the data receiving unit 122
receives the differential signals corresponding to the
video data and the differential signals corresponding to
the audio data and control data, which are transmitted
unidirectionally from the data transmitting unit 112,
10 through the TMDS channels #0 through #5. In this case,
the HDMI receiver 82 reproduces the pixel clock from the
received data, and performs reception in synchronization
with the pixel clock (the TMDS clock).
[0048]
15 The transmission channels of the HDMI system
include not only the above described TMDS channels and
the TMDS clock channel, but also transmission channels
called a DDC (Display Data Channel) and a CEC line. The
DDC is formed with two signal lines (not shown) included
20 in the cable 200. The DDC is used by the data
transmitting unit 112 to read E-EDID (Enhanced Extended
Display Identification Data) from the data receiving unit
122.
[0049]
25 That is, the data receiving unit 122 includes not
only the HDMI receiver 82 but also an EDID ROM (EEPROM)
that stores the E-EDID as the capability information
indicating the configuration/capability thereof. In
response to a request from the control unit 113, for
30 example, the data transmitting unit 112 reads, via the
DDC, the E-EDID from the data receiving unit 122 that is
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connected via the cable 200.
[0050]
The data transmitting unit 112 sends the read EEDID
to the control unit 113. The control unit 113
5 stores the E-EDID into a flash ROM or DRAM (not shown).
Based on the E-EDID, the control unit 113 can recognize
the setting of the capability of the data receiving unit
122. For example, the control unit 113 recognizes
whether the sink device 120 including the data receiving
10 unit 122 is compatible with the new HDMI as well as the
current HDMI. The CEC line is formed with one signal
line (not shown) included in the cable 200, and is used
for performing bidirectional communications of control
data between the data transmitting unit 112 and the data
15 receiving unit 122.
[0051]
The cable 200 also includes a line (HPD line)
connected to a pin called HPD (Hot Plug Detect). The
source device can use the HPD line to detect a connection
20 with the sink device. It should be noted that this HPD
line is also used as a HEAC- line forming a bidirectional
communication path. The cable 200 also includes a power
line (+5 V Power Line) that is used for supplying power
from the source device to the sink device. The cable 200
25 further includes a utility line. This utility line is
also used as a HEAC+ line forming a bidirectional
communication path.
[0052]
Fig. 5 shows an example data structure of TMDS
30 transmission data. Fig. 5 shows the periods of
respective types of transmission data to be transmitted
23
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in a case where image data of B pixels in the horizontal
direction and A lines in the vertical direction through
the TMDS channels #0 through #2 or the TMDS channels #0
through #5. Depending on the types of transmission data,
5 there are three periods in the video field in which
transmission data is transmitted through TMDS channels of
an HDMI. The three types of periods are a video data
period, a data island period, and a control period.
[0053]
10 Here, a video field period is a period from the
active edge of a vertical synchronization signal to the
active edge of the next vertical synchronization signal.
This video field period is divided into a horizontal
blanking interval, a vertical blanking interval, and an
15 active video period (Active Video). This active video
period is formed by subtracting the horizontal blanking
interval and the vertical blanking interval from the
video field period. The video data period is assigned to
the active video period. In the video data period, data
20 of effective pixels (active pixels) of B pixels and A
lines forming uncompressed image data of one screen.
[0054]
The data island period and the control period are
assigned to the horizontal blanking interval and the
25 vertical blanking interval. In the data island period
and the control period, auxiliary data is transmitted.
That is, the data island period is assigned to part of
the horizontal blanking interval and the vertical
blanking interval. In this data island period, data not
30 concerning control in the auxiliary data, such as a
packet of audio data, is transmitted. The control period
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is assigned to the other portions of the horizontal
blanking interval and the vertical blanking interval. In
this control period, data concerning control in the
auxiliary data, such as a vertical synchronization signal,
5 a vertical synchronization signal, and a control packet,
is transmitted.
[0055]
The pin assignment in the receptacle 111 is now
described. First, the pin assignment in the current HDMI
10 (Type A) is described. The pin assignment in the current
HDMI is a first pin assignment. Fig. 6(a) shows the pin
assignment in the current HDMI. TMDS Data#i+ and TMDS
Data#i-, which are differential signals of the TMDS
channels #i (i = 0 through 2), are transmitted through
15 two lines that are differential lines. Some pins (the
pins with pin numbers 7, 4, and 1) are assigned to TMDS
Data#i+, and some (the pins with pin numbers 9, 6, and 3)
are assigned to TMDS Data#i-. The pins with pin numbers
8, 5, and 2 are assigned to TMDS Data#i Shield (i = 0
20 through 2).
[0056]
TMDS Clock+ and TMDS Clock-, which are differential
signals of the TMDS clock channel, are transmitted
through two lines that are differential lines. The pin
25 with pin number 10 is assigned to TMDS Clock+, and the
pin with pin number 12 is assigned to TMDS Clock-. The
pin with pin number 11 is assigned to TMDS Clock Shield.
[0057]
A CEC signal that is control data is transmitted
30 through the CEC line. The pin with pin number 13 is
assigned to the CEC signal. A SDA (Serial Data) signal
25
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such as E-EDID is transmitted through a SDA line. The
pin with pin number 16 is assigned to the SDA signal. A
SCL (Serial Clock) signal that is the clock signal to be
used for synchronization at the time of
5 transmission/reception of the SDA signal is transmitted
through a SCL line. The pin with pin number 15 is
assigned to the SCL signal. The above described DDC line
is formed with the SDA line and the SCL line.
[0058]
10 The pin with pin number 19 is assigned to HPD/HEAC-.
The pin with pin number 14 is assigned to Utility/HEAC+.
The pin with pin number 17 is assigned to DDC/CEC
Ground/HEAC Shield. The pin with pin number 18 is
assigned to the power supply (+5 V Power).
15 [0059]
Next, the pin assignment in the new HDMI is
described. The pin assignment in the new HDMI is a
second pin assignment. Fig. 6(b) shows the pin
assignment in the new HDMI. TMDS Data#i+ and TMDS ,
20 Data#i-, which are differential signals of the TMDS
channels #i (i = 0 through 5), are transmitted through
two lines that are differential lines. Some pins (the
pins with pin numbers 1, 4, 7, 10, 2, and 8) are assigned
to TMDS Data#i+, and some (the pins with pin numbers 3, 6,
25 9, 12, 5, and 11) are assigned to TMDS Data#i-.
[0060]
A CEC signal that is control data is transmitted
through the CEC line. The pin with pin number 13 is
assigned to the CEC signal. A SDA (Serial Data) signal
30 such as E-EDID is transmitted through a SDA line. The
pin with pin niomber 16 is assigned to the SDA signal. A
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SCL (Serial Clock) signal that is the clock signal to be
used for synchronization at the time of
transmission/reception of the SDA signal is transmitted
through a SCL line. The pin with pin number 15 is
5 assigned to the SCL signal. The above described DDC line
is formed with the SDA line and the SCL line.
[0061]
The pin with pin number 19 is assigned to HPD/HEAC-.
The pin with pin number 14 is assigned to Utility/HEAC+.
10 The pin with pin number 17 is assigned to DDC/CEC
Ground/HEAC Shield. The pin with pin number 18 is
assigned to the power supply (+5 V Power).
[0062]
As described above, in the new HDMI pin assignment
15 (see Fig. 6(b)), the terminals (the pins with pin numbers
2, 5, 8, and 11) used as the shield terminals in the
current HDMI pin assignment (see Fig. 6(a)) are used as
data terminals. In the new HDMI pin assignment, the
terminals (the pins with pin numbers 10 and 12) used as
20 the signal terminals for the differential signals of the
clock signals in the current HDMI pin assignment are used
as data terminals.
[0063]
The data transmitting unit 112 of the source device
25 110 selects the current HDMI pin assignment shown in Fig.
6(a) when operating in the current HDMI operating mode,
and selects the new HDMI pin assignment shown in Fig.
6(b) when operating in the new HDMI operating mode. The
pin assignment in the receptacle 111 of the source device
30 110 has been described so far. Although not described in
detail, the pin assignment in the receptacle 121 of the
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sink device 120 is the same as above in a case where the
data receiving unit 122 of the sink device 120 is
compatible with both the current HDMI and the new HDMI.
[0064]
5 Figs. 7(a) and 7(b) show the pin layouts in the
receptacle 111 of the source device 110. Fig. 7(a) shows
the pin layout in the current HDMI, and Fig. 7(b) shows
the pin layout in the new HDMI. When the current HDMI
pin assignment is selected as the pin assignment in the
10 receptacle 111, the pins with pin numbers 2, 5, 8, and 11
are in a grounded state in the source device 110 and the
sink device 120, or are in a grounded state in the sink
device 120 and are in a high impedance state in the
source device 110, or are in a high impedance state in
15 the sink device 120 and are in a grounded state in the
source device 110. Although not described in detail, the
pin layout in the receptacle 121 of the sink device 120
is the same as above in a case where the data receiving
unit 122 of the sink device 120 is compatible with both
20 the current HDMI and the new HDMI.
[0065]
Fig. 8(a) shows an exemplary structure of the
current HDMI cable used as the cable 200. In this
current HDMI cable, three data line pairs are formed as
25 shielded twisted pair cable units so as to achieve
respective characteristics. Also, a clock line pair and
a utility/HPD line pair to achieve the HEAC function are
formed as shielded twisted pair cable units.
[0066]
30 Fig. 8(b) shows an exemplary structure of a
shielded twisted pair cable unit. This shielded twisted
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pair cable unit has a structure in which two electric
wires 3 and a drain wire 4 are coated with a shielding
member 5. Each of the electric wires 3 is formed with a
core 1 coated with a coating portion 2.
5 [0067]
In the current HDMI cable, the drain wires of the
shielded twisted pair cable units of data and clock, are
connected to pins of plugs attached to the end portions
of this cable. In this case, the respective drain wires
10 are connected to the pins (terminals) corresponding to
the respective shield terminals (the shielding pins with
pin numbers 2, 5, 8, and 11) of the above described
receptacle (the current HDMI pin layout). Those shield
terminals are grounded in the source device 110 and the
15 sink device 120. With this structure, the drain wires of
the respective shielded twisted pair cable units of data
and clock are grounded when the plug is connected to the
receptacle (the current HDMI pin layout).
[0068]
20 Fig. 9 shows an exemplary structure of the new HDMI
cable used as the cable 200. In this new HDMI cable, six
data line pairs are formed as shielded twisted pair cable
units so as to achieve respective characteristics. Also,
a utility/HPD line pair to achieve the HEAC function is
25 formed as a shielded twisted pair cable unit.
[0069]
The new HDMI cable includes a larger number of
copper cables to be connected than in the current HDMI
cable (see Fig. 8(a)). In this new HDMI cable, the drain
30 wires of the respective shielded twisted pair cable units
connected by special pins of the plugs at both ends of
29
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the cable are connected to metallic shells of the plugs.
With this structure, the shielding pins are opened, and
an increase in the number of required pins in the plugs
is avoided. The plugs in the new HDMI cable are the same
5 as the plugs in the current HDMI cable. As described
above, where the drain wires of the respective shielded
twisted pair cable units are connected to the metallic
shells of the plugs, the shells of the receptacles into
which the plugs are inserted are connected to the ground
10 level, and accordingly, the differential pair lines can
be shielded.
[0070]
Fig. 10 shows another exemplary structure of the
new HDMI cable used as the cable 200. The substantial
15 structure of this new HDMI cable is the same as that of
the above described new HDMI cable shown in Fig. 9,
except for having a flat cross-sectional shape. With
such a flat cross-sectional shape, the cross-sectional
area can be made smaller, and impedance matching can be
20 more easily achieved.
[0071]
[Operating mode control in the current HDMI and the new
HDMI]
Next, the operating mode control in the source
25 device 110 and the control unit 113 is described in
greater detail. As described above, in a case where the
control unit 113 determines that the cable 200 is
compatible with the new HDMI, and the sink device 120 is
compatible with the new HDMI, the control unit 113
30 controls the data transmitting unit 112 to operate in the
new HDMI operating mode. In the other cases, the control
30
SP310249WO00
unit 113 controls the data transmitting unit 112 to
operate in the current HDMI operating mode.
[0072]
The flowchart in Fig, 11 shows the procedures in an
5 operating mode control operation of the control unit 113.
In step STl, the control unit 113 starts the operation,
and moves on to the procedure of step ST2. In step ST2,
the control unit 113 determines whether the source device
110 or the data transmitting unit 112 is compatible with
10 the new HDMI. Storing beforehand the capability
information about the source device 110 (the data
transmitting unit 112) to which the control unit 113
belongs, the control unit 113 can easily perform the
determination. In this embodiment, it is apparent that
15 the source device 110 is compatible with the new HDMI,
the control unit 113 may skip this determination
procedure of step ST2.
[0073]
When having determined that the source device 110
20 is compatible with the new HDMI, the control unit 113
determines in step ST3 whether the sink device 120 or the
data receiving unit 122 is compatible with the new HDMI.
This determination will be described later in detail.
When having determined that the sink device 120 is
25 compatible with the new HDMI, the control unit 113 moves
on to the procedure of step ST4. In step ST4, the
control unit 113 determines whether the cable 200 is
compatible with the new HDMI. This determination will be
described later in detail.
30 [0074]
When having determined that the cable 200 is
31
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compatible with the new HDMI, the control unit 113 moves
on to the procedure of step ST5. In step ST5, the
control unit 113 controls the data transmitting unit 112
to operate in the new HDMI operating mode. When having
5 determined in step ST2 that the source device 110 is not
compatible with the new HDMI, in step ST3 that the sink
device 120 is not compatible with the new HDMI, or in
step ST4 that the cable 200 is not compatible with the
new HDMI, the control unit 113 moves on to the procedure
10 of step ST6. In step ST6, the control unit 113 controls
the data transmitting unit 112 to operate in the current
HDMI operating mode.
[0075]
When having determined in step ST3 that the sink
15 device 120 is compatible with the new HDMI, for example,
the control unit 113 transmits the result of the last
operation mode determination to the sink device 120 via
the cable 200. The determination result is transmitted
as control information such as an InfoFrame from the
20 source device 110 prior to data transmission, for example.
In the sink device 120, based on the operating mode
determination result from the source device 110, the
control unit 123 controls the data receiving unit 122 to
operate in the same operating mode as the data
25 transmitting unit 112 of the source device 110.
[0076]
When controlling in step ST5 the data transmitting
unit 112 to operate in the new HDMI operating mode, the
control unit 113 may perform the control so that the UI
30 screen indicating the control result is displayed on a
display unit (a display) as shown in Fig. 12(a), for
32
SP310249WO00
example. With this UI screen, the user can easily
recognize that the source device 110 and the sink device
120 are connected by the new HDMI. The display unit (the
display) on which the UI screen is displayed may be a
5 display unit (a display) (not shown) provided on the
source device 110, or may be a display unit (a display)
(not shown) provided on the sink device 120. The same
applies to the respective UI screens described below.
[0077]
10 When having determined in step ST4 that the cable
2 00 is not compatible with the new HDMI, and moving on to
the procedure of step ST6, the control unit 113 may
perform the control so that the UI screen indicating the
result is displayed on the display unit (the display) as
15 shown in Fig. 12(c), for example. With this UI screen,
the user can easily recognize that the source device 110
and the sink device 120 are compatible with the new HDMI,
but only the cable 200 is not compatible with the new
HDMI, and can take measures by replacing the cable 200
20 with a new HDMI cable or the like.
[0078]
In the procedures shown in the flowchart in Fig. 11,
when having determined in step ST4 that the cable 200 is
compatible with the new HDMI, the control unit 113
25 immediately moves on to step ST5, and controls the data
transmitting unit 112 to operate in the new HDMI
operating mode. When having determined in step ST4 that
the cable 200 is compatible with the new HDMI, however,
the control unit 113 may also allow the user to select
30 the new HDMI or the current HDMI (the conventional HDMI)
by exchanging commands beforehand through a line such as
33
SP310249WO00
the CEC line prior to data transmission.
[0079]
In that case, the control unit 113 performs the
control so that the UI screen for the selection is
5 displayed on the display unit (the display) as shown in
Fig. 12(b), for example. Based on this UI screen, the
user selects either the new HDMI or the current HDMI.
Fig. 12(b) illustrates a situation where the "new HDMI"
is selected. In accordance with the selection by the
10 user, the control unit 113 controls the data transmitting
unit 112 to operate in the new HDMI or current HDMI
operating mode.
[0080]
The flowchart in Fig. 13 shows the procedures in an
15 operating mode control operation to be performed by the
control unit 113 in that case. In Fig. 13, the same
steps as those in Fig. 11 are denoted by the same
reference numerals as those in Fig. 11, and detailed
explanation of them is not repeated herein. When having
20 determined in step ST4 that the cable 200 is compatible
with the new HDMI, the control unit 113 moves on to the
procedure of step ST7. In step ST7, the control unit 113
performs control so that the UI screen for selecting
either the new HDMI or the current HDMI is displayed on
25 the display unit (the display) . The UI may be
transmitted as a video signal from the source device 110
through the cable 200, or the sink device 120 may be
instructed to display the UI.
[0081]
30 After that, the control unit 113 moves on to the
procedure of step ST8. In step ST8, as the control unit
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123 transmits a notification as to an operation performed
by the user with a remote controller or the like through
a line such as the CEC line, the control unit 113
determines which of the HDMIs, the new HDMI and the
5 current HDMI, has been selected by the user. When the
user has selected the new HDMI, the control unit 113
controls in step ST5 the data transmitting unit 112 to
operate in the new HDMI operating mode. When the User
has selected the current HDMI, on the other hand, the
10 control unit 113 controls in step ST6 the data
transmitting unit 112 to operate in the current HDMI
(conventional HDMI) operating mode.
[0082]
(Determination on whether the sink device is
15 compatible with the new HDMI)
The methods used by the control unit 113 to determine
whether the sink device 120 is compatible with the new
HDMI are now described. The determination methods
include the following first determination method and
20 second determination method, for example.
[0083]
(First determination method)
Based on EDID that is read from the sink device 120
by using the DDC line (the SDA line and the SCL line) of
25 the cable 200, the control unit 113 determines whether
the sink device 120 is compatible with the new HDMI. The
EDID has a data structure that is specified in a format.
Flag information indicating whether the sink device 120
is compatible with the new HDMI (new transmission) is
30 newly defined at a predetermined site in the EDID.
[0084]
35
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Fig. 14 shows an example of the flag information
newly defined in the EDID. Originally, the EDID is a
data structure indicating various kinds of capabilities
of the sink device 120. For ease of explanation, Fig. 14
5 shows only the bytes relevant to this invention in the
EDID in a minimized manner. In bit 2, 1-bit flag
information "New Rx Sink" indicating whether the sink
device 120 is compatible with the new HDMI is written.
In bit 1, 1-bit flag information "New Cable" indicating
10 whether the cable 200 is compatible with the new HDMI is
newly defined.
[0085]
When the above described 1-bit flag information
"New Rx Sink" exists in the EDID read from the sink
15 device 120, the control unit 113 determines that the sink
device 120 is compatible with the new HDMI. That is, in
a case where the sink device 120 is compatible only with
the current HDMI, the above described 1-bit flag
information "New Rx Sink" does not exist in the EDID read
20 from the sink device 120.
[0086]
(Second determination method)
By performing communication with the sink device
120 through the cable 200, the control unit 113
25 determines whether the sink device 120 is compatible with
the new HDMI. For example, the control unit 113
determines whether the sink device 120 is compatible with
the new HDMI by using commands through the CEC line.
[0087]
30 Also, the control unit 113 determines whether the
sink device 120 is compatible with the new HDMI by
36
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performing communication with the sink device 120 through
the bidirectional communication path (the HEAC function)
formed with the utility line and the HPD line, for
example. Further, the control unit 113 determines
5 whether the sink device 120 is compatible with the new
HDMI by exchanging some kind of signals through an unused
line such as the utility line until transmission is
allowed.
[0088]
10 (Determination on whether the cable is compatible
with the new HDMI)
Next, the methods used by the control unit 113 to
determine whether the cable 200 is compatible with the
new HDMI are described. The determination methods
15 include the following first through fourth determination
methods, for example. The first through third
determination methods are determination methods that are
implemented by using the information providing function
of the cable 200 in a case where the cable 200 is the new
20 HDMI cable.
[0089]
(First determination method)
In the case of the first determination method, the
new HDMI cable contains an LSI (Large Scale Integration)
25 in a plug as shown in Fig. 15, for example. In a
situation where +5 V is supplied from the source device
110, for example, the sink device 120 requests an output
from this LSI through the CEC protocol while the HPD is
set at L. The sink device 120 in this case is a sink
30 device compatible with the new HDMI. In response to the
output request from the sink device 120, the LSI reports
37
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the values of registers mounted in the LSI (a
notification of compatibility with the new HDMI, and
cable property data such as the transmittable data band)
to the sink device 120 through the CEC protocol.
5 [0090]
The sink device 120 adds the information reported
from the LSI to the EDID thereof. After the adding, the
sink device 120 switches the HPD to H, to instruct the
source device 110 to read the EDID. Based on the EDID
10 that is read from the sink device 120, the control unit
113 determines whether the cable 200 is compatible with
the new HDMI. That is, when there is information or the
like indicating that the cable 200 is compatible with the
new HDMI, the control unit 113 determines that the cable
15 200 is compatible with the new HDMI.
[0091]
In the above description, the sink device 120
requests an output from the LSI through the CEC protocol.
However, the source device 110 may request an output from
20 the LSI through the CEC protocol, and receive a report of
register values (the notification of compatibility with
the new HDMI, and the cable property data such as the
transmittable data band) directly from the LSI.
[0092]
25 (Second determination method)
In the case of the second determination method, the
new HDMI cable also contains an LSI in a plug as shown in
Fig. 15, for example. When the HPD is switched from L to
H, for example, the source device 110 reads and acquires
30 EDID from the sink device 120, with the EDID indicating
the capability thereof. In this case, the data written
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in the EEPROM in the sink device 120 is serially
transmitted through the SDA/SCL line, so that the EDID is
reported to the source side.
[0093]
5 The LSI observes the line through the EDID
information, or the SDA/SCL signal, during the EDID
transmission. When the flag information indicating
whether the cable 200 is compatible with the new HDMI
(the bit 1 in the predetermined bytes in Fig. 14) is
10 transmitted, the LSI changes the bit value to a state
where the cable 200 is compatible with the new HDMI, or a
state where the flag is on. Specifically, the data in
the EDIDROM (EEPROM) in the sink device 120 is "00000100".
However, the LSI in the cable rewrites the data during
15 transmission, and the data is "00000110" when the source
device 110 receives the data.
[0094]
Based on the EDID that is read from the sink device
120, the control unit 113 determines whether the cable
20 200 is compatible with the new HDMI. Specifically, when
the flag information indicating whether the cable 200 is
compatible with the new HDMI (the bit 1 in the
predetermined bytes in Fig. 14) indicates compatibility
with the new HDMI, the control unit 113 determines that
25 the cable 200 is compatible with the new HDMI.
[0095]
Fig. 16 shows an example of the EDID data rewrite
circuit of the LSI in the cable. This LSI includes a
counter that counts clocks on the SCL line, and a driver
30 that rewrites the data on the SDA line based on the count
value of the counter.
39
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[0096]
(Third determination method)
In the case of the third determination method, the
new HDMI cable con-tains a RF tag chip (LSI) in a plug as
5 shown in Fig. 17, for example. The RF tag chip stores a
notification of compatibility with the new HDMI, and
information such as the transmittable data band. A RF
tag read chip (LSI) is also contained in the receptacle
111 of the source device 110. In this case, near field
10 communication is performed between the RF tag read chip
of the receptacle 111 and the RF tag chip of the plug,
and the information stored in the RF tag chip is read by
the RF tag read chip.
[0097]
15 Based on the information read by the RF tag read
chip, the control unit 113 determines whether the cable
200 is compatible with the new HDMI. That is, when
information indicating that the cable 200 is compatible
with the new HDMI is read by the RF tag read chip, the
20 control unit 113 determines that the cable 200 is
compatible with the new HDMI.
[0098]
In the above description, near field communication
is performed between the RF tag read chip of the
25 receptacle 111 of the source device 110 and the RF tag
chip of the plug, and the information stored in the RF
tag chip is read at the side of the source device 110.
However, near field communication may be performed
between a RF tag read chip of the receptacle 121 of the
30 sink device 120 and the RF tag chip of the plug, and the
information stored in the RF tag chip may be read at the
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side of the sink device 120 and then be provided to the
side of the source device 110, for example.
[0099]
(Fourth determination method)
5 In the case of the fourth determination method, the
control unit 113 measures the electrical properties of
the cable 200, to determine whether the cable 200 is
compatible with the new HDMI. As shown in Fig. 18, the
control unit 113 of the source device 110 transmits a
10 test signal (a digital signal) for measurement and
detection to the pin 2 and the pin 5, and the control
unit 123 of the sink device 120 receives the signals.
Although the pair of signal lines connected to the pin 2
and the pin 5 do not form a differential signal
15 transmission path in the current HDMI cable, the pair of
signal lines connected to the pin 2 and the pin 5 form a
differential signal transmission path in the new HDMI
cable (see Figs. 6(a) and 6(b)).
[0100]
20 The control unit 123 of the sink device 120 sends
the received digital signal to the side of the source
device 110 through another path (such as the DDC line
indicated as SCL/SDA in the HDMI, the GEO line, or the
utility line). The control unit 113 of the source device
25 110 determines whether the digital signal sent from the
sink device 120 is the same as the digital signal
transmitted therefrom, to determine whether the cable 200
is compatible with the new HDMI. That is, when the
received digital signal and the transmitted digital
30 signal are identical, the control unit 113 determines
that the cable 200 is compatible with the new HDMI.
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[0101]
As shown in Fig. 19(a), in a case where the cable
200 is a current HDMI cable, the pair of signal lines
connected to the pin 2 and the pin 5 do not form a
5 shielded twisted pair cable. Therefore, in determining
that the cable 200 is compatible with the current HDMI,
the aspect that "a high-speed test signal cannot be
transmitted" is used. At this point, a signal not
concerning the pin 2 may be applied to the pin 1 or the
10 pin 3 related to the pin 2, and the interference may be
used. With this interference, transmitting a high-speed
test signal becomes more difficult.
[0102]
As shown in Fig. 19(b), in a case where the cable
15 200 is the new HDMI cable, on the other hand, the pair of
signal lines connected to the pin 2 and the pin 5 form a
shielded twisted pair cable. Therefore, in determining
that the cable 200 is compatible with the new HDMI, the
aspect that "a high-speed test signal can be transmitted"
20 is used. Even if a signal not concerning the pin 2 is
applied to the pin 1 or the pin 3 at this point, those
pins are shielded independently of each other, and the
applied signal does not interfere with the pin 2, and
does not affect transmission of the test signal.
25 [0103]
Here, the test signal is the data the source device
110 can output at the highest speed, and is random data
that is long enough to be evaluated as 10"^, which is
guaranteed as a bit error rate in the HDMI. Since a
30 frame buffer memory for normal video reproduction is
installed in the sink device 120, a memory specially for
42
SP310249WO00
the transmission test may not be necessary.
[0104]
In the above description, only when the received
digital signal and the transmitted digital signal are
5 identical, does the control unit 113 determine that the
cable 200 is compatible with the new HDMI. The control
unit 113 may lower the data transmission speed, and
conduct the same test as above. By repeating the above
described determining process until the matching is
10 achieved, the capability of the cable is confirmed, and
the cable is determined to be compatible with the new
HDMI. However, only data that is transmittable at the
transmission speed or lower may be transmitted. In this
case, there is a possibility that the current HDMI cable
15 is determined to be compatible with the new HDMI.
[0105]
In the above description, the pin 2 and the pin 5
are used. However, instead of those pins, the pin 8 and
the pin 11, which have the same relationship as those
20 pins between the current HDMI cable and the new HDMI
cable, may be used. That is, the pair of signal lines
connected to the pin 8 and the pin 11 do not form a
differential signal transmission path in the current HDMI
cable, but the pair of signal lines connected to the pin
25 8 and the pin 11 form a differential signal transmission
path in the new HDMI cable (see Figs. 6(a) and 6(b)).
[0106]
In the above description, the digital signal (the
test signal) the source device 110 has transmitted to the
30 sink device is sent from the sink device 120, which has
received the digital signal, to the source device 110,
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and a check is made to determine whether the transmitted
signal and the received signal are identical at the side
of the source device 110. However, a predetermined
pattern may be transmitted as a digital signal (a test
5 signal), and the sink device 120 may determine whether
the received digital signal is correct, and send only the
result to the source device 110 through a line such as
the CEC line or add the information to the E-EDID thereof.
[0107]
10 As described above, in the AV system 100 shown in
Fig. 1, the data transmitting unit 112 of the source
device 110 has the new HDMI operating mode as well as the
current HDMI operating mode. Here, the number of
differential signal channels for transmitting digital
15 signals such as video data is three in the current HDMI,
but is six in the new HDMI. Accordingly, by using the
new HDMI, signals can be transmitted at a high data rate.
Also, when the sink device 120 and the cable 200 are not
compatible with the new HDMI, the current HDMI (the
20 conventional HDMI) is used, to secure backward
compatibility.
[0108]
<2. Modifications>
In the above described embodiments, the plugs of
2 5 the new HDMI cable has the same shape as the plugs of the
current HDMI cable (the conventional HDMI cable).
However, the shape of the plugs of the new HDMI cable can
be different from the shape of the plugs of the current
HDMI cable so that, when either the source device or the
30 sink device is not compatible with the new HDMI, those
devices are not connected by the new HDMI cable.
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[0109]
Fig. 20(a) shows the shape of each plug of the
current HDMl cable, and Fig. 20(b) shows the shape of
each receptacle of a source device and a sink device
5 compatible only with the current HDMI. On the other hand,
Fig. 20(c) shows the shape of each plug of the new HDMI
cable, and Fig. 20(d) shows an example of the shape of
each receptacle of a source device and a sink device
compatible with the new HDMI. Fig. 21(a) is a
10 perspective view of a plug of the current HDMI cable, and
Fig. 21(b) is a perspective view of a plug of the new
HDMI cable.
[0110]
Each plug of the new HDMI cable has a convex
15 portion (indicated by an arrow P). Each receptacle of a
source device and a sink device that are compatible with
the new HDMI has a concave portion (indicated by an arrow
Q) corresponding to the convex portion of each plug. In
this case, the shape of each receptacle of the source
20 device and the sink device compatible with the new HDMI
matches the shape of each plug of the new HDMI cable, and
is designed to include the shape of each plug of the
current HDMI cable.
[0111]
25 The shape of the plugs of the new HDMI cable and
the shape of the receptacles of the source device and the
sink device compatible with the new HDMI are designed as
described above, so that the new HDMI cable can be
connected to the receptacles of the source device and the
30 sink device compatible with the new HDMI. However, the
new HDMI cable cannot be connected to the receptacles of
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a source device and a sink device that are compatible
only with the current HDMI. Therefore, when either the
source device or the sink device is not compatible with
the new HDMI, those devices are not connected by the new
5 HDMI cable. That is, only when both the source device
and the sink device are compatible with the new HDMI, can
those devices be connected by the new HDMI cable.
[0112]
As described above, the shape of each receptacle of
10 a source device and a sink device that are compatible
with the new HDMI matches the shape of each plug of the
new HDMI cable, and is designed to include the shape of
each plug of the current HDMI cable. Accordingly, the
current HDMI cable can be connected not only to the
15 receptacles of a source device and a sink device that are
compatible only with the current HDMI, but also to the
receptacles of a source device and a sink device that are
compatible with the new HDMI.
[0113]
2 0 Also, in the above described embodiments, the
number of differential signal channels is six in the new
HDMI, while the number of differential signal channels
for transmitting digital signals such as video data is
three in the current HDMI. However, the number of
25 differential signal channels for transmitting digital
signals such as video data is not limited to six, but may
be four, five, seven, or the like. For example, the
number of differential signal channels for transmitting
digital signals such as video data is five, and the clock
30 frequency is made 1.2 times higher. With this, the same
data transmission speed as that in the case of six
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channels can be achieved.
[0114]
Also, in the above described embodiments, this
invention is applied to an AV system in which a source
5 device and a sink device are connected by a digital
interface compliant with the HDMI standard. This
invention can also be applied to any AV system in which
those devices are connected by a digital interface
compliant with some other standard.
10
INDUSTRIAL APPLICABILITY
[0115]
This invention can be applied to an AV system or
the like that is formed by connecting a source device and
15 a sink device with a digital interface, for example.
REFERENCE SIGNS LIST
[0116]
81 HDMI transmitter
20 82 HDMI receiver
100 AV system
110 Source device
111 Receptacle
112 Data transmitting unit
25 113 Control unit
120 Sink device
121 Receptacle
122 Data receiving unit
123 Control unit
30 200 Cable
201, 202 Plug
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CLAIMS
1. A transmitting device comprising:
a digital signal transmitting unit configured to
5 transmit a digital signal to an external device via a
transmission path with a differential signal, and have a
first operating mode involving a first number of channels
for the differential signal and a second operating mode
involving a second number of channels for the
10 differential signal, the second number being larger than
the first number;
an operating mode determining unit configured to
determine whether the external device and the
transmission path are compatible with the second
15 operating mode; and
an operation control unit configured to control the
operation of the digital signal transmitting unit, based
on the determination performed by the operating mode
determining unit.
20
2. The transmitting device according to claim 1,
further comprising:
a receptacle configured to connect a plug of the
transmission path thereto, the transmission path being a
25 cable, the receptacle having a plurality of pins,
wherein the digital signal transmitting unit
selects a first pin assignment in the first operating
mode, and selects a second pin assignment in the second
operating mode, the second pin assignment being different
30 from the first pin assignment.
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3. The transmitting device according to claim 2,
wherein, in the second pin assignment, a terminal that is
used as a shield terminal corresponding to a signal
terminal for a differential signal for a digital signal
5 and/or a clock signal in the first pin assignment is used
as a signal terminal for a differential signal for
transmitting a digital signal.
4. The transmitting device according to claim 2,
10 wherein, in the second pin assignment, a signal terminal
for a differential signal for a clock signal in the first
pin assignment is used as a signal terminal for a
differential signal for transmitting a digital signal.
15 5. The transmitting device according to claim 1,
wherein the operating mode determining unit determines
whether the external device is compatible with the second
operating mode, based on capability information about the
external device, the capability information being read
20 from the external device via the transmission path.
6. The transmitting device according to claim 1,
wherein the operating mode determining unit determines
whether the external device is compatible with the second
2 5 operating mode, by performing communication with the
external device via the transmission path.
7. The transmitting device according to claim 1,
wherein the operating mode determining unit determines
30 whether the transmission path is compatible with the
second operating mode, by using an information providing
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function of the transmission path compatible with the
second operating mode.
8. The transmitting device according to claim 7,
5 wherein
the information providing function of the
transmission path compatible with the second operating
mode is a function to report to the external device that
the transmission path is compatible with the second
10 operating mode,
the external device has a function to add the
information reported from the transmission path to
capability information thereof, and
the operating mode determining unit determines
15 whether the transmission path is compatible with the
second operating mode, based on the capability
information read from the external device via the
transmission path.
20 9. The transmitting device according to claim 7,
wherein
the information providing function of the
transmission path compatible with the second operating
mode is a function to rewrite information indicating
25 whether the transmission path is compatible with the
second operating mode, to indicate compatibility with the
second operating mode, the information being contained in
capability information read from the external device, and
the operating mode determining unit determines
30 whether the transmission path is compatible with the
second operating mode, based on the capability
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information read from the external device via the
transmission path.
10. The transmitting device according to claim 7,
5 wherein
the information providing function of the
transmission path compatible with the second operating
mode is a function to provide information indicating that
the transmission path is compatible with the second
10 operating mode through near field communication, and
the operating mode determining unit determines
whether the transmission path is compatible with the
second operating mode, based on whether the information
indicating that the transmission path is compatible with
15 the second operating mode is provided from the
transmission path through the near field communication.
11. The transmitting device according to claim 1,
wherein the operating mode determining unit transmits a
20 differential signal for a predetermined digital signal to
the external device by using a pair of signal lines in
the transmission path, and performs the determination
based on a signal sent from the external device, the pair
of signal lines not forming a differential signal
25 transmission path in the first operating mode, the pair
of signal lines forming a differential signal
transmission path in the second operating mode.
12. The transmitting device according to claim 11,
30 wherein the signal sent from the external device is a
signal indicating whether a received digital signal
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obtained from the predetermined differential signal
received by the external device is correct.
13. The transmitting device according to claim 11,
5 wherein the signal sent from the external device is a
received digital signal obtained from the predetermined
differential signal received by the external device.
14. The transmitting device according to claim 1,
10 further comprising:
an information transmitting unit configured to
transmit the result of the determination performed by the
operating mode determining unit to the external device
via the transmission path.
15
15. The transmitting device according to claim 2,
wherein a shape of the receptacle matches a shape of the
plug of the cable compatible with the second operating
mode, and includes a shape of the plug of the cable
20 compatible with the first operating mode.
16. The transmitting device according to claim 1,
further comprising:
a display control unit configured to control
25 display on a display unit for providing control
information about the operation control unit to a user.
17. The transmitting device according to claim 16,
wherein, when the operating mode determining unit
30 determines that the external device and the transmission
path are compatible with the second operating mode, the
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display control unit performs control to display a user
interface screen on the display unit, the user interface
screen being for causing a user to select one of the
first operating mode and the second operating mode for
5 the digital signal transmitting unit.
18. A transmitting method comprising:
a digital signal transmitting step of transmitting
a digital signal to an external device via a transmission
10 path with a differential signal in a first operating mode
involving a first number of channels for the differential
signal or in a second operating mode involving a second
number of channels for the differential signal, the
second number being larger than the first number;
15 an operating mode determining step of determining
whether the external device and the transmission path are
compatible with the second operating mode; and
an operation controlling step of controlling the
operation of the digital signal transmitting step, based
20 on the determination performed in the operating mode
determining step.
19. A receiving device comprising:
a digital signal receiving unit configured to
25 receive a digital signal from an external device via a
transmission path with a differential signal, and have a
first operating mode involving a first number of channels
for the differential signal and a second operating mode
involving a second number of channels for the
30 differential signal, the second number being larger than
the first number;
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an information receiving unit configured to receive,
from the external device, operating mode information
indicating which one of the first operating mode and the
second operating mode is to be selected; and
5 an operation control unit configured to control the
operation of the digital signal receiving unit, based on
the operating mode information received by the
information receiving unit.
10 20. A receiving method comprising:
a digital signal receiving step of receiving a
digital signal from an external device via a transmission
path with a differential signal in a first operating mode
involving a first number of channels for the differential
15 signal or in a second operating mode involving a second
number of channels for the differential signal, the
second number being larger than the first number;
an information receiving step of receiving, from
the external device, operating mode information
20 indicating which one of the first operating mode and the
second operating mode is to be selected; and
an operation controlling step of controlling the
operation in the digital signal receiving step, based on
the operating mode information received in the
25 information receiving step.
21. A transmitting/receiving system formed by
connecting a transmitting device and a receiving device
via a transmission path,
30 the transmitting device comprising:
a digital signal transmitting unit configured to
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transmit a digital signal to the receiving device via the
transmission path with a differential signal, and have a
first operating mode involving a first number of channels
for the differential signal and a second operating mode
5 involving a second number of channels for the
differential signal, the second number being larger than
the first number;
an operating mode determining unit configured to
determine whether the receiving device and the
10 transmission path are compatible with the second
operating mode;
a transmitting operation control unit configured to
control the operation of the digital signal transmitting
unit, based on the determination performed by the
15 operating mode determining unit; and
an information transmitting unit configured to
transmit operating mode information about the digital
signal transmitting unit to the receiving device via the
transmission path,
20 the receiving device comprising:
a digital signal receiving unit configured to
receive the digital signal from the transmitting device
via the transmission path with the differential signal,
and have the first operating mode involving the first
25 number of channels for the differential signal and the
second operating mode involving the second number of
channels for the differential signal;
an information receiving unit configured to receive
the operating mode information from the transmitting
30 device via the transmission path; and
a receiving operation control unit configured to
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control the operation of the digital signal receiving
unit, based on the operating mode information received by
the information receiving unit.
5 22. A cable that transmits a digital signal from a
transmitting device to a receiving device with a
differential signal having a predetermined number of
channels, the cable comprising:
an information providing function unit configured
10 to provide information incjicating signal transmission
capability of the cable to one of the transmitting device
and the receiving device.
23. The cable according to claim 22, wherein the
15 information providing function unit provides the
information indicating the signal transmission capability
of the cable to one of the receiving device -afid the
transmitting device via the cable, in response to a
request from the one of the receiving device and the
2 0 transmitting device.
24. The cable according to claim 22, wherein the
information providing function unit rewrites part of
capability information read by the transmitting device
25 from the receiving device via the cable.
25. The cable according to claim 22, wherein the
information providing function unit provides the
information indicating the signal transmission capability
30 of the cable to one of the transmitting device and the
receiving device through near field communication.