Abstract:
An apparatus for swapping output high-speed multimedia signals. In one embodiment the apparatus comprises a plurality of inputs coupled to a multimedia transmitter; a plurality of outputs coupled to a plurality of pins of a multimedia interface connector; and a controller for generating a control signal for configuring an order in which the plurality of inputs are routed to the plurality of outputs, wherein the order in which the plurality of inputs are routed to the plurality of outputs is set to enable un-crossing of one or more conducting wires coupling the plurality of inputs to the multimedia transmitter and to enable un-crossing of one or more conducting wires coupling the plurality of outputs and the plurality of pins of the multimedia interface connector.

Description:
TECHNICAL FIELD 
     This invention generally relates to the connectivity of multimedia interface devices. 
     BACKGROUND OF THE INVENTION 
     The high-definition multimedia interface (HDMI™) is a compact audio/video connector interface for transmitting uncompressed digital streams. The HDMI connects digital audio/video (or multimedia) sources (e.g., a set-top box, a DVD player, a personal computer, a video game console, etc.) to a compatible digital audio device and/or video monitor such as a digital television. 
     An exemplary block diagram of an HDMI link  100  is shown in  FIG. 1 . A multimedia source  110  transmits high speed data using transition minimized differential signaling (TMDS®) characters. The TMDS characters are high-speed signals encapsulating video, audio, and auxiliary data and are carried over three TMDS channels  130 - 1 ,  130 - 2 , and  130 - 3 . A multimedia sink  120  receives the TMDS characters and converts them into digital video and audio streams, data packets, and control signals. 
     A clock, typically running at the video pixel rate, is transmitted on a clock channel  140  and is used by the multimedia sink  120  as a frequency reference for data recovery on the three TMDS channels  130 - 1 ,  130 - 2 , and  130 - 3 . In addition, configuration, system-level control, management and status information is exchanged between the multimedia source  110  and the multimedia sink  120 . The system-level control includes a display data channel (DDC) and a consumer electronics control (CEC) which are transmitted over channels: SCL  150 , SDA  160 , and CEC  170 . Signals transported over the SCL  150 , SDA  160 , and CEC  170  channels are considered as low-speed signals. A hot plug detector (HPD) signal  180  is sent from the multimedia sink  120  and multimedia source  110 . 
     As illustrated in  FIG. 2A , the various high speed multimedia signals are generated using a multimedia transmitter  210  and decoded using a multimedia receiver  220 . Typically, the transmitter  210  and receiver  220  are implemented in an integrated circuit (IC). The output/input high speed multimedia signals from the transmitter/receiver are carried over conducting wires  230 - 1  to  230 - 4 , on a printed circuit board (PCB)  240 , to a multimedia interface connector  250 , e.g., an HDMI connector. Specifically, the wires  230 - 1 ,  230 - 2 , and  230 - 3  are respectively connected to pins  251 ,  252  and  253  in the connector  250 . The pins  251 ,  252  and  253  are connected to channels carrying high-speed multimedia signals (e.g., the TMDS channels  130 - 1 ,  130 - 2 , and  130 - 3 ). The wire  230 - 4  is coupled to the clock&#39;s pin  254  of, e.g., the clock channel  140 . Typically, each conducting wire  230 - 1  to  230 - 4  is a differential pair. As can be noted there is a one-to-one connection between each pin in the connector  250  to its respective output of transmitter&#39;s  210  output or an input receiver&#39;s  220  input. 
     The performance of a multimedia interface system, and in particular an HDMI system, strongly depends on the quality of the physical infrastructure carrying the signals between the transmitter  210  and receiver  220 . Specifically, if the conducting wires  230  are not directly wired between the output/input of the transmitter/receiver and the connector  250  the quality of the signals, carried over the wires  230 - 1  to  230 - 4 , is significantly reduced. Specifically, the signal integrity and signal-to-noise-ratio (SNR) of at least high-speed multimedia signals are affected. 
     As illustrated in  FIGS. 2B and 2C , in some cases, the wires  230 - 1  to  230 - 4  carrying the high-speed multimedia signals are crossed due to mechanical constraints that determine the locations of the connector  250 , transmitter  210 , receiver  220 . For example, in  FIG. 2B , the conducting wires  230 - 1  to  230 - 4  are crossed on the PCBs  240  due to the location of the connector  250  and the receiver  220  and transmitter  210 . In  FIG. 2C , the conducting wires  230 - 1  to  230 - 4  between the transmitter  210  and pins of the connector  250  are crossed. Typically, in such designs the signals are routed through different metal layers and vias on the PCBs  240 . As a result, the quality of the signals is significantly reduced. 
     Therefore, it would be advantageous to have a solution that would enable a direct connection between a circuit for processing high-speed multimedia signals and a multimedia connector. 
     SUMMARY OF THE INVENTION 
     Certain embodiments of the invention include an apparatus for swapping output high-speed multimedia signals. The apparatus comprises a plurality of inputs coupled to a multimedia transmitter; a plurality of outputs coupled to a plurality of pins of a multimedia interface connector; and a controller for generating a control signal for configuring an order in which the plurality of inputs are routed to the plurality of outputs, wherein the order in which the plurality of inputs are routed to the plurality of outputs is set to enable un-crossing of one or more conducting wires coupling the plurality of inputs to the multimedia transmitter and to enable un-crossing of one or more conducting wires coupling the plurality of outputs and the plurality of pins of the multimedia interface connector. 
     Certain embodiments of the invention also include an apparatus for swapping input high-speed multimedia signals. The apparatus comprises a plurality of inputs coupled to a multimedia interface connector; a plurality of outputs coupled to a multimedia receiver; and a controller for generating a control signal for configuring an order in which the plurality of inputs are routed to the plurality of outputs, wherein the order in which the plurality of inputs are routed to the plurality of outputs is set to enable un-crossing of one or more conducting wires coupling the plurality of outputs to the multimedia receiver and to enable un-crossing of one or more conducting wires coupling the plurality of inputs and the plurality of pins of the multimedia interface connector. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       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. 
         FIG. 1  is a block diagram of an HDMI system. 
         FIG. 2A  is a typical wiring of a receiver and transmitter to connectors in a multimedia interface system. 
         FIGS. 2B and 2C  are examples for designs of multimedia interface systems where wires are crossed on PCBs of such systems. 
         FIG. 3  is an exemplary diagram of an apparatus utilized for swapping transmitted high-speed multimedia signals realized in accordance with an embodiment of the invention. 
         FIG. 4  illustrates how the apparatus shown in  FIG. 3  can be utilized for swapping TMDS channels in an HDMI system. 
         FIG. 5  is an exemplary diagram of an apparatus utilized for swapping received high-speed multimedia signals realized in accordance with an embodiment of the invention. 
         FIG. 6  illustrates how the apparatus described in  FIG. 5  can be utilized to swap TMDS channels in an HDMI system. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     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. 
     A method and apparatus that enables point-to-point connections between an integrated circuit (IC) that processes the multimedia signals to a connector is described. Certain embodiments of the method and apparatus enhance the quality of high speed multimedia signals transmitted in multimedia systems. This is performed by internally swapping the multimedia signals without changing the location of the electric circuit board and/or the connector. In a preferred embodiment, the multimedia signals include at least TMDS characters carried over TMDS channels and an HDMI clock sent over a clock channel, where the connector is an HDMI connector. 
       FIG. 3  shows an exemplary block diagram of an apparatus  300  for swapping transmitted high-speed multimedia signals realized in accordance with an embodiment of the invention. The apparatus  300  includes a number of N inputs  330 - 1  through  330 -N and a number of N outputs  320 - 1  through  320 -N as well as a controller  345  that outputs a control signal  340 . The inputs  330 - 1  through  330 -N are directly coupled to the outputs  350 - 1  through  350 -N of a multimedia transmitter  310 . That is, there are no cross connections between the transmitter  310  and the apparatus  300 . The outputs  320 - 1  through  320 -N are connected to the conducting wires leading to a connector  360  are configurable under the control of the controller  345 . That is, the controller  345  outputs a control signal  340  that determines the order in which the inputs  330 - 1  through  330 -N will be routed to the outputs  320 - 1  through  320 -N. For example, the output  320 - 2  may output a signal at the input  330 - 1 , the input  330 - 2  may be routed to the output  320 - 1 , and so on. The control signal  340  is generated based on the layout (i.e., a physical location of the connector  360  and transmitter  310 ). The layout may be pre-programmed at the controller  345 . In another embodiment, the controller  345  may run a process that automatically detects the pins&#39; locations at the connector  360  and transmitter  310 , and generates the control signal  340  based on the pins&#39; locations. As the outputs  350  of the transmitter  310  are fixed and the position of the connector  360  is also fixed (as determined by the mechanical constraints of the system) the ability to have programmable outputs  320 - 1  through  320 -N allows designing a circuit with uncrossed conducting wires connecting the transmitter  310  and a multimedia interface connector  360 . 
     This is further illustrated in  FIG. 4  which shows how the apparatus  300  can be utilized to swap TMDS channels of the multimedia interface system shown in  FIGS. 2B and 2C . The inputs  330 - 1 ,  330 - 2 ,  330 - 3  and  330 - 4  (of the apparatus  300 ) are respectively connected to the TMDS channel outputs of the multimedia transmitter  210 . The apparatus  300  is configured to swap between the TMDS channels TMDS 2  and TMDS 3  as well as the TMDS channel TMDS 1  and the clock channel. That is, the TMDS 1  channel&#39;s input  330 - 1  is now routed to the output  320 - 4  and the TMDS 2  channel&#39;s  330 - 2  is directed to the output  320 - 3 , the TMDS 3  channel&#39;s input  330 - 3  is directed to the output  320 - 2 . In addition, the clock channel&#39;s input  330 - 4  is routed to the output  320 - 1 . In one embodiment the apparatus  300  is placed on a PCB between the wiring crossing point and the connector. This allows directly wiring the outputs  320  to the connector&#39;s  250  pins, without cross connections. In accordance with an embodiment of the invention, the apparatus  300  may be an analog switch or a digital switch. The apparatus  300  can be integrated in the transmitter  310  or be connected outside of the transmitter or even connected to or integrated with the connector. 
       FIG. 5  shows an exemplary block diagram of an apparatus  500  utilized for swapping input high-speed multimedia signals realized in accordance with an embodiment of the invention. The apparatus includes a number of N inputs  520 - 1  through  520 -N and a number of N outputs  530 - 1  through  530 -N as well as a controller  545  that outputs a control signal  540 . The outputs  530  are directly coupled to the inputs  550  of a multimedia receiver  510 . That is, there are no cross connections between the receiver  510  and the apparatus  500 . The inputs  520  are connected to the conducting wires leading to a multimedia interface connector  560  and are configurable under the control of the controller  545 . That is, the controller  545  determines the order in which the inputs  520 - 1  through  520 -N will be routed to the outputs  530 - 1  through  530 -N. For example, a signal at an input  520 - 1  may be directed to an output  530 - 2 , a signal at an input  520 - 2  may be routed to an output  530 - 1 , and so on. The control signal  540  is generated based on the layout (i.e., a physical location of the connector  560  and receiver  510 ). The layout may be pre-programmed at the controller  545 . In another embodiment, the controller  545  may run a process that automatically detects the pins&#39; locations at the connector  560  and receiver  510 , and generates the control signal  540  based on the pins&#39; locations. As the inputs  550 - 1  through  550 -N of the receiver  510  are fixed and the position of the connector  560  is also fixed (as determined by the mechanical constraints of the system) the ability to have programmable outputs  530 - 1  through  530 -N allows for designing a circuit with uncrossed conducting wires connecting the receiver  510  and the connector  560 . In accordance with an embodiment of the invention, the apparatus  500  may be an analog switch or a digital switch. The apparatus  500  can be integrated in the receiver  510  or connected outside the receiver or even connected to or integrated with the connector. 
       FIG. 6  depicts how the apparatus  500  can be utilized to swap TMDS channels of the multimedia interface system shown in  FIGS. 2B and 2C . In the example, the apparatus  500  is configured to swap between the TMDS channels TMDS 2  and TMDS 3  as well as the channel TMDS 1  and the clock channel. That is, the TMDS 2  channel&#39;s input  520 - 3  is now routed to the output  530 - 2  and the TMDS 3  channel&#39;s input  520 - 2  is directed to the output  530 - 3 . Similarly, the clock channel&#39;s input  520 - 1  is forwarded to the output  530 - 4  and the TMDS 1  channel&#39;s  520 - 4  is directed to the output  530 - 1 . This allows directly wiring the inputs  520  to the multimedia interface connector&#39;s  250  pins. 
     In some multimedia interface system designs high-speed multimedia signals are carried over differential pairs, each of which is a pair of conductors. In some cases, due to mechanical constraints, the conductors are twisted over the PCB, thereby degrading the quality of a signal carried over a differential pair. It should be apparent to one of ordinary skill in the art that the teachings disclosed herein can be also utilized to untwist conductors of differential pairs carrying the high-speed multimedia signals. Furthermore, it should be apparent to one of ordinary skill in the art that teachings described herein can be easily adapted to swap multimedia signals of other digital display interface standards, such as a DisplayPort™, and the like. 
     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.