Patent Application
20110063501
This invention generally relates to the connectivity of electronic display devices.
The high-definition multimedia interface (HDMI) is a compact audio/video connector interface for transmitting uncompressed digital streams. The HDMI connects a digital multimedia (or audio/video) source (e.g., a set-top box, a DVD player, a personal computer, a video game console, etc.) to a compatible digital sink, such as a digital television. The HDMI is fully described in the HDMI Specification version 1.4 published on Jun. 5, 2009, incorporated herein by reference in its entirety merely for the useful understanding of the background of the invention.
A HDMI cable is a transport medium including three transition minimized differential signaling (TMDS®) channels utilized to transfer video, audio, and auxiliary data encapsulated in TDMS characters and the transmission is synchronized using a high-frequency clock signal running over a clock channel. The TDMS and clock channels are differential pairs. A HDMI cable also includes the following channels: a display data channel (DDC_SCL and DDC_SDA), a consumer electronics control (CEC), and a hot-plug detect (HPD) signal which originates at the sink. The HDMI interface is implemented using a HDMI cable and connectors, each of which includes 19 pins. A source and sink connectors have the same configuration. Table 1 lists the pins in a type A HDMI connector (either a source or sink).
DisplayPort™ is a standard that defines a digital display interface of a new digital audio/video interconnect. The DisplayPort is intended to be used primarily between a computer and its display monitor, or a computer and a home-theater system. The DisplayPort standard is fully described in the DisplayPort Specification Version 1.1a published in Jan. 11, 2008, by the video electronics standards association (VESA), incorporated herein by reference in its entirety merely for the useful understanding of the background of the invention.
Transport channels of a DisplayPort interface include a main link, an auxiliary (AUX), and a hot plug detect (HPD). The main link is a unidirectional channel that allows data transfers over up to 4 lanes that carry clock signals in addition to the video/audio streams. Each lane is an AC-coupled differential pair. The auxiliary channel is a bi-directional half-duplex channel that carries control and management information and the HPD channel is used by a sink device to interrupt a source device when a plug is connected or disconnected. The DisplayPort interface is facilitated using a proprietary cable and connectors, each of which includes 20 pins. The DisplayPort cable is a cross cable, i.e., a source and sink connector has a different configuration. Table 2 lists the pins and their signals of source and sink DisplayPort connectors.
Multimedia interfaces that allow connectivity of both the HDMI and DisplayPort (will be referred hereinafter as a “dual mode connectivity interface”) have been recently developed. Specifically, such interfaces can process data compliant with the HDMI and DisplayPort. However, even if a source or sink device has dual-mode connectivity capabilities, the connection is either through a HDMI or a DisplayPort connector. In the related art there is no physical medium (e.g., a cable), other than HDMI or DisplayPort cables, to connect source and sink devices having different connector types.
Interoperability between HDMI and DisplayPort is defined in the VESA DisplayPort Interoperability Guideline Version 1.1a published on Feb. 5, 2009, which requires a dedicated adapter and a HDMI cable. As illustrated in
Certain embodiments of the invention include multimedia interface cable. The multimedia comprises a first multimedia connector including a plurality of contact pins of at least high-speed multimedia signals and control signals; a second multimedia connector including a plurality of contact pins of least high-speed multimedia signals and control signals; a plurality of un-crossing conducting wires for coupling the plurality of contact pins of the high-speed multimedia signals in the first multimedia connector to the plurality of contact pins of the high-speed multimedia signals in the second multimedia connector; and a plurality of conducting wires for coupling the plurality of contact pins of the control signals in the first multimedia connector to the plurality of contact pins of the control signals in the second multimedia connector.
Certain embodiments of the invention further include an apparatus for enabling interoperability between multimedia display interfaces, the apparatus is operable in a source multimedia device. The apparatus comprises an input coupled to a multimedia connector; and a comparator for determining a type of the multimedia display interface of a sink multimedia device connected to the source multimedia device based on at least a voltage level of a clock signal received through the multimedia connector.
Certain embodiments of the invention also include an apparatus for enabling interoperability between multimedia display interfaces, the apparatus is operable in a sink multimedia device. The apparatus comprises an input interface coupled to a multimedia connector; and a detector for determining a type of the multimedia display interface of a source multimedia device connected to the sink multimedia device based on at least one control signal received through the multimedia connector.
The subject matter that is regarded as the invention is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other objects, features and advantages of the invention will be apparent from the following detailed description taken in conjunction with the accompanying drawings.
It is important to note that the embodiments disclosed by the invention are only examples of the many advantageous uses of the innovative teachings herein. In general, statements made in the specification of the present application do not necessarily limit any of the various claimed inventions. Moreover, some statements may apply to some inventive features but not to others. In general, unless otherwise indicated, singular elements may be in plural and vice versa with no loss of generality. In the drawings, like numerals refer to like parts through several views.
One embodiment of the invention, illustrated in
In accordance with an embodiment of the invention both dual mode connectivity interfaces 222 and 242 implement an automatic recognition technique for determining the type of the multimedia interface (e.g., a HDMI or DisplayPort) connected at the other end of the cable 200, and configuring the respective device accordingly. For example, if the source device 210 also supports a HDMI, the dual mode connectivity interface 222 recognizes that HDMI data is transmitted by the source device 210, and sets the sink device 220 to process such type of data. As will be described in detail below, each of the dual mode connectivity interfaces implement a different automatic recognition technique.
The multimedia interface cable 200 comprises a HDMI connector 310 including 19 pins and a DisplayPort connector 320 with 20 pins. The wiring between the connectors 310 and 320 is depicted in
To allow proper connection, such as the configuration illustrated in
To allow a proper connection between a source HDMI (dual mode) and a sink DisplayPort, such as the configuration illustrated in
Control signals (in the configurations depicted both in
Upon recognition of the type of the sink, the source dual mode connectivity interface 242 is set to be compliant with the multimedia interface type of the sink device. This includes, for example, setting analog circuits of an analog front-end (not shown) of the interface 242 to a mode of operation compliant with the type of the sink, setting the power level of the interface 242 and adapting passive components of control signals by, for example, disabling the AC component of AUX channel and enabling a CEC signal when setting the interface 242 to operate in a HDMI mode.
The detector 510 implements the sensing of an auxiliary channel using a logic circuit (not shown) that generates a decision regarding the type of a source device based on the logic values of the signals AUX_CHP and AUX_CHN (e.g., pins 15 and 16 on connector 310). Specifically, if a logic value of both signals AUX_CHP and AUX_CHN is ‘0’, the source device is a DisplayPort device not being powered; if the value of AUX_CHP is ‘0’ and the value of the AUX_CHN is ‘1’ the source is a DisplayPort device; if the logic values of AUX_CHP and AUX_CHN are ‘1’ and ‘0’ respectively, no device is connected at the other end of the cable; and if a logic value of both AUX_CHP and AUX_CHN is ‘1’, the source is a HDMI device.
In another embodiment the detector 510 senses the CEO and AUX_PWR signals using a logic circuit (not shown) to determine the type of a source device according to logic values of the CEO signal (e.g., pin 13 on connector 310) and the AUX_PWR signal (e.g., pin 18 on connector 310). Specifically, if logic values of both CEO and AUX_PWR signals are ‘1’, the source is a HDMI device not being powered; if the logic values of AUX_PWR and CEO signals are ‘1’ and ‘0’ respectively, the source is a DisplayPort device; and if the value of AUX_PWR is ‘0’, no device is connected at the other end of the cable.
Yet in another embodiment the detector 510 includes a comparator (not shown) that compares the voltage level on an AUX_PWR signal (e.g., pin 18 on connector 310) to a predefined threshold. Specifically, if the voltage level of the AUX_PWR is below 0.8V, no device is connected at the source; if the voltage level of the AUX_PWR signal is between 3V and 4V, the source is a DisplayPort device; and when the amplitude of AUX_PWR is above 4.5V the source is a HDMI device. It should be noted that the logic values ‘1’ and ‘0’ may also be referred to as high and low values respectively. Furthermore, the indicated logic values of ‘1’ and ‘0’ and voltage values of the predefined threshold are only examples used for ease of understanding. One of ordinary skill in the art recognizes that the value may be designed to be any value based on design expediency.
Upon recognition of the type of a source device, the sink dual mode connectivity interface 222 is set to be compliant with the multimedia interface type of the source device. This includes, for example, setting analog circuits of an analog front-end of the interface 222 to a mode of operation compliant with the source device.
It should be appreciated that the multimedia interface cable 200 together with the automatic sensing techniques implemented between the dual mode connectivity interfaces 222 and 242 provide complete interoperability of at least HDMI and DisplayPort. Specifically, the teachings of the invention disclosed herein can be utilized to connect a DisplayPort compliant source device to a HDMI compliant sink device and a HDMI compliant source device to a DisplayPort compliant sink device using either the cable 200 or a standard HDMI cable without using any dedicated adapter, such as described in the VESA standard referenced above or any other type of an active adapter.
Furthermore, connections such as those illustrated in
While the present invention has been described at some length and with some particularity with respect to the several described embodiments, it is not intended that it should be limited to any such particulars or embodiments or any particular embodiment, but it is to be construed with references to the appended claims so as to provide the broadest possible interpretation of such claims in view of the prior art and, therefore, to effectively encompass the intended scope of the invention. Furthermore, the foregoing describes the invention in terms of embodiments foreseen by the inventor for which an enabling description was available, notwithstanding that insubstantial modifications of the invention, not presently foreseen, may nonetheless represent equivalents thereto. All examples and conditional language recited herein are intended for pedagogical purposes to aid the reader in understanding the principles of the invention and the concepts contributed by the inventors to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions.
