CN214412882U

CN214412882U - Circuit compatible with DP and DP + + protocol low-speed signals for line speed forwarding

Info

Publication number: CN214412882U
Application number: CN202022640175.2U
Authority: CN
Inventors: 俞剑明; 王祚栋; 毛蔚; 白昀
Original assignee: Fei Ang Innovation Technology Nantong Co ltd
Current assignee: Fei Ang Innovation Technology Nantong Co ltd
Priority date: 2020-11-16
Filing date: 2020-11-16
Publication date: 2021-10-15
Anticipated expiration: 2030-11-16

Abstract

The utility model provides a circuit compatible with DP, DP + + protocol low-speed signal for line speed forwarding, comprising a DP transmitting end module and a DP receiving end module; the DP transmitting end module analyzes the interface signal of the source end in real time, compresses the interface signal and transmits the compressed interface signal to the DP receiving end, receives a reverse communication signal from the DP receiving end module, decompresses the signal in real time and transmits the decompressed signal to the source end; the DP receiving end module analyzes the signal received from the DP transmitting end in real time, decompresses the signal and transmits the decompressed signal to the display equipment end, and compresses the signal of the display equipment end in real time and transmits the compressed signal to the DP receiving end module; and the analysis module of the DP transmitting end module and the analysis module of the DP receiving end module reasonably switch the IO direction according to the actual communication state, so that the low-delay bidirectional communication is realized. The utility model discloses can completely realize AUX +, AUX-signal transmission, support DP and HDMI, DVI's protocol conversion.

Description

Circuit compatible with DP and DP + + protocol low-speed signals for line speed forwarding

Technical Field

The utility model relates to a microelectronics communication technology field, in particular to circuit that compatible DP, DP + + agreement low-speed signal carried out line speed and forwardded.

Background

With the development of display technology and the increasing resolution of displays, the demand of consumers for displays is gradually shifting from 4k displays to 8k displays. The Display Port protocol is an open source audio/video data protocol maintained by VESA organization, and is more and more favored by host manufacturers, middle and high-end Display card manufacturers and Display manufacturers. From DP1.2, DP1.4 to the latest DP2.0, the maximum data transfer rate of DP (display interface) interfaces has increased from 21.6Gbps to 32.5Gbps to 77.37 Gbps. With such a trend, copper wire transmission has gradually become a bottleneck of display data transmission, and light entering copper has receded into an inevitable trend of development of display technology. The real realization of long-distance high-quality optical fiber display transmission is to process high-quality transmission of high-speed signals, and the optical fiber transmission of out-of-band signals, i.e. low-speed signals such as AUX +, AUX- (one pin in DisplayPort protocol) in DP protocol, is also an urgent problem to be solved. These low speed signals play an important role in display control, user manipulation, and the like. Therefore, the low-cost, low-delay, high-compatibility optical fiber transmission of these low-speed signals plays an important role for the realization of the optical fiber DP. However, half duplex communication, AUX +, AUX-is not well compatible with unidirectional communication, which is fiber optic communication. In addition, the DP + + protocol also provides a compatibility requirement between the DP protocol and HDMI (High Definition Multimedia Interface) and DVI (Digital Visual Interface) protocols, and how to correctly select the actually used transmission protocol becomes a problem. Accordingly, the problem of optical fiber transmission of SDA (Serial Data Line), SCL (Serial Clock Line) and CEC (Consumer Electronics Control) signals needs to be solved.

In the prior art, some solutions have appeared for low speed signal transmission of audio/video data transmission line protocols:

(1) and electrifying to read DPCD information of the display equipment terminal, and then transmitting the DPCD information to the source terminal in an optical fiber communication mode. The method can effectively copy a DPCD of the display equipment end at the source end, so that the DPCD information of the display equipment is correctly read when the far end initiates AUX communication. However, the scheme has a defect that the scheme cannot support functions of real-time communication such as I2C over AUX, HDCP (High-bandwidth Digital Content Protection technology) and the like.

(2) Using a store-and-forward mode, firstly receiving AUX (Auxiliary communication Channel of dp) information, and when a device end response is needed, using AUX DEFER to respond that the received AUX DEFER main device waits for a certain delay and then initiates re-access. The master device and the slave device communicate by using a custom protocol, and exchange data at two ends in a packet exchange mode. And after the slave device finishes reading the data, sending a packet to update the cache of the master device, and the master device can read the data after retrying. However, the scheme has the disadvantages of long response delay, and the requirement of waiting for reading the response of the slave device and then feeding back the response to the source device. And if other communication is carried out after AUX DEFER, the former communication fails, so the compatibility of the scheme is poor

The compatible problem of HDMI and DVI protocols is not processed in the existing pure light DP scheme, and the DP cable can not work normally when equipment of certain DP + + (display Port multiMode, multi-mode DP protocols compatible with DVI, HDMI and DP) or an adapter for connecting certain DP to the HDMI or DVI is connected.

Therefore, in order to solve the problems in the prior art, completely realize the transmission of AUX +, AUX-signals and support the protocol conversion of DP, HDMI and DVI, a circuit compatible with DP and DP + + protocol low-speed signals for line-speed forwarding is needed.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a compatible DP, DP + + agreement low-speed signal carries out the circuit that the line speed forwarded, the said circuit includes DP transmitting terminal module and DP receiving terminal module;

the DP transmitting end module analyzes the interface signal of the source end in real time, compresses the interface signal and transmits the compressed interface signal to a DP receiving end, receives a reverse communication signal from the DP receiving end module, decompresses the signal in real time and transmits the decompressed signal to the source end;

the DP receiving end module analyzes the signal received from the DP transmitting end in real time, decompresses the signal and transmits the decompressed signal to the display equipment end, and compresses the signal of the display equipment end in real time and transmits the compressed signal to the DP receiving end module;

and the analysis module of the DP transmitting end module and the analysis module of the DP receiving end module reasonably switch the IO (Input/Output) direction according to the actual communication state, so that the low-delay bidirectional communication is realized.

Preferably, the DP transmitter module includes an AUX decoding and forwarding unit, a DDC (Direct Digital Control) decoding and forwarding unit, a CONFIG parsing unit, a protocol switching unit, a CEC decoding and forwarding unit, a CEC arbitration unit, a time division multiplexing unit, a channel coding unit, a synchronization unit, a time division demultiplexing unit, a transmitting circuit, and a receiving circuit.

Preferably, the DP receiving end module includes an AUX decoding and forwarding unit, a DDC decoding and forwarding unit, a CONFIG parsing unit, a protocol switching unit, a CEC decoding and forwarding unit, a CEC arbitration unit, a time division multiplexing unit, a channel coding unit, a synchronization unit, a time division multiplexing unit, a transmitting circuit, and a receiving circuit.

Preferably, in the DP origination module, the CONFIG parsing unit determines the communication protocol according to a level of a source CONFIG1 pin and a CONFIG1 (a pin in the DisplayPort protocol) signal of the display device end transmitted from the optical path.

Preferably, in the DP originating module, if the CONFIG analysis result shows that DP communication is performed,

the AUX decoding and forwarding unit analyzes AUX + and AUX-signals at the source end in real time, and the protocol switching unit selects AUX and AUX-signal transmission.

Preferably, in the DP originating module, if the CONFIG parsing result shows that HDMI, DVI communication is performed,

the DDC decoding and forwarding unit analyzes the SDA and SCL signals of the source end in real time, and the protocol switching unit selects the SDA and SCL signals for transmission.

Preferably, in the DP receiving end module, the CONFIG parsing unit determines the communication protocol according to the level of the display device CONFIG1 pin and a CONFIG1 signal of the source end transmitted from the optical path.

Preferably, in the DP receiving end module, if the CONFIG analysis result indicates to perform DP communication,

the AUX decoding and forwarding unit analyzes AUX + and AUX-signals of the display end in real time, and the protocol switching unit selects AUX + and AUX-signal transmission.

Preferably, in the DP sink module, if the CONFIG parsing result shows that HDMI/DVI communication is performed,

then the DDC decoding and forwarding unit analyzes SDA and SCL signals of the display end in real time, and the protocol switching unit selects the SDA and SCL signals for transmission.

The utility model provides a pair of compatible DP, DP + + agreement low-speed signal carry out the circuit that the line speed forwarded, can completely realize AUX +, AUX-signal transmission, support DP and HDMI, DVI's protocol conversion guarantees the low cost of scheme, low time delay, high reliability, and high compatibility is to realizing pure light DP transmission.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, as claimed.

Drawings

Further objects, functions and advantages of the present invention will become apparent from the following description of embodiments of the present invention, with reference to the accompanying drawings, in which:

fig. 1 schematically shows an overall structure diagram of a circuit for forwarding a low-speed signal compatible with a DP, DP + + protocol at a line speed.

Fig. 2 shows a schematic structural diagram of the DDC decoding and forwarding unit of the DP transmitter module of the present invention.

Fig. 3 shows the structure diagram of the DDC decoding and forwarding unit of the DP receiving end module of the present invention.

Fig. 4 shows a schematic structural diagram of the AUX parsing and forwarding unit of the DP transmitter module of the present invention.

Fig. 5 shows a schematic structural diagram of the AUX parsing and forwarding unit of the DP receiving end module of the present invention.

Fig. 6 shows a schematic diagram of the circuit of the present invention combined with high-speed signal forwarding in another embodiment of the present invention.

Fig. 7 shows another embodiment of the present invention, in which the circuit DP receiving end module is connected to the HDMI protocol conversion interface.

Detailed Description

The objects and functions of the present invention and methods for accomplishing the same will be apparent by reference to the exemplary embodiments. However, the present invention is not limited to the exemplary embodiments disclosed below; it can be implemented in different forms. The nature of the description is merely to assist those skilled in the relevant art in a comprehensive understanding of the specific details of the invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the drawings, the same reference numerals denote the same or similar parts, or the same or similar steps.

In order to solve the problem that exists among the prior art, the utility model provides a compatible DP, DP + + agreement low-speed signal carry out the circuit that the line speed forwarded to complete AUX +, AUX-signal transmission, support DP and HDMI, DVI's protocol conversion. The full-duplex communication of low-speed signals such as AUX +, AUX-, SDA, SCL, CEC, HPD (Hot Plug Detection), CONFIG and the like is realized by using optical fiber transmission, and the automatic protocol conversion of DP, HDMI and DVI is supported.

As shown in fig. 1 the utility model discloses the DDC of DP transmitting terminal module decodes and forwards the structural schematic diagram of unit, according to the utility model discloses an embodiment, a compatible DP, DP + + agreement low-speed signal carry out the circuit that the line speed forwarded, including DP transmitting terminal module and DP receiving terminal module. The source end is connected with the DP transmitting end module, and the DP receiving end module is connected with the display equipment end.

And the DP transmitting end module analyzes the interface signal of the source end in real time, transmits the signal to the DP receiving end after being compressed, receives the reverse communication signal from the DP receiving end module, and transmits the signal to the source end after being decompressed in real time.

In the embodiment, the DP transmitting end module analyzes, time-division multiplexes, and codes a channel for a low-speed signal at a source end, and the transmitting circuit reaches the DP receiving end module through a photoelectric/electro-optical conversion path composed of a laser, an optical fiber, and a photodetector, and then reaches a low-speed signal interface at a display device end through a receiving circuit, a synchronization unit, a decoding unit, and a demultiplexing unit of the DP receiving end module.

And the DP receiving end module analyzes the signal received from the DP transmitting end in real time, decompresses the signal and transmits the decompressed signal to the display equipment end, and transmits the signal of the display equipment end to the DP receiving end module after real-time compression.

The low-speed signal of the display equipment end reaches a DP transmitting end through signal analysis, time division multiplexing and channel coding, and a transmitting circuit reaches a DP transmitting end through an optical fiber and then passes through a DP transmitting end module receiving circuit, a synchronization unit, a decoding unit and a demultiplexing unit to reach a low-speed signal interface of a source end.

And the analysis module of the DP transmitting end module and the analysis module of the DP receiving end module are reasonably switched according to the actual communication state, so that low-delay bidirectional communication is realized.

The following explains the utility model discloses a DP transmitting terminal module and DP receiving terminal module.

DP transmitting terminal module

The DP transmitting terminal module comprises an AUX decoding and forwarding unit, a DDC decoding and forwarding unit, a CONFIG analyzing unit, a protocol switching unit, a CEC decoding and forwarding unit, a CEC arbitration unit, a time division multiplexing unit, a channel coding unit, a synchronization unit, a time division multiplexing unit, a sending circuit and a receiving circuit.

The DP transmitting end module performs communication by using a time division multiplexing unit and a channel coding mode. And the time division multiplexing unit circularly acquires the low-speed signal of the source end and sends the low-speed signal to the display equipment end through the DP receiving end module. According to the utility model discloses an embodiment, but time division multiplex unit is to low-speed signal's transmission order random arrangement.

In the DP transmitting end module, the channel coding uses improved Manchester coding communication, so that normal communication can be realized without completely synchronizing clock signals of the DP transmitting end module and the DP receiving end module.

The AUX signal is encoded by Manchester and is communicated at the speed of about 1Mhz, and the main clock frequency of the whole system is set to be more than 100Mhz in consideration of the bandwidth overhead of encoding and time division multiplexing of the system.

In the DP transmitting end module, a receiving circuit receives signals in a channel, and the DP transmitting end has a local clock, so that after receiving the signals, bit synchronization and frame synchronization are carried out on the received signals through a synchronization unit.

In the DP transmitting end module, an AUX decoding and converting unit analyzes source end AUX + and AUX-signals, a DDC decoding and converting unit analyzes source end SDA and SCL signals, and a CEC decoding and converting unit analyzes source end CEC signals.

The system comprises an AUX decoding and converting unit, a DDC decoding and converting unit and a CEC decoding and converting unit, wherein the AUX decoding and converting unit, the DDC decoding and converting unit and the CEC decoding and converting unit are used for forwarding a low-speed signal of a source end in real time by taking a local clock as an interval, and simultaneously analyzing the actual communication direction of a state machine control signal through a real-time running protocol.

The utility model discloses analytic unit does not adopt the mode that above-mentioned line speed was forwardded with the analytic signal of the form that the storage was forwardded, can reduce communication delay to within 50ns, strengthens the compatibility of ultimate demonstration transmission scheme to different equipment greatly.

And the DP transmitting end module analyzes the CONFIG signal of the source end, and selects a DP or HDMI or DVI mode for communication in a subsequent channel according to the CONFIG signal. And the DP and DP + + ports have better compatibility with some DP protocol conversion interfaces.

According to the utility model discloses an in the embodiment, in the DP originating module, the CONFIG analytic unit is according to the CONFIG1 signal of the level of source end CONFIG1 foot and the display device end that transmits from the light path, judgement communication protocol. For example, if the level of the CONFIG1 pin and the CONFIG1 signal of the display device side transmitted from the optical path are both DP communication, the CONFIG analysis result indicates that DP communication is performed. The level of the ONFIG1 pin and the CONFIG1 signal of the display device end transmitted from the optical path are both HDMI/DVI communication, and the CONFIG analysis result is displayed to carry out the HDMI/DVI communication.

In the DP originating module, if the CONFIG analysis result shows that DP communication is performed,

the AUX decoding and converting unit analyzes AUX + and AUX-signals at the source end in real time, and the protocol switching unit selects AUX + and AUX-signal transmission.

In the DP transmitting end module, if the CONFIG analysis result shows that the HDMI and DVI communication is performed,

the DDC decoding and converting unit analyzes the SDA and SCL signals of the source end in real time, and the protocol switching unit selects the SDA and SCL signals for transmission.

DP receiving end module

The DP receiving end module comprises an AUX decoding and forwarding unit, a DDC decoding and forwarding unit, a CONFIG analyzing unit, a protocol switching unit, a CEC decoding and forwarding unit, a CEC arbitration unit, a time division multiplexing unit, a channel coding unit, a synchronization unit, a time division multiplexing unit, a transmitting circuit and a receiving circuit.

The DP receiving end module performs communication by using a time division multiplexing unit and a channel coding method. The time division multiplexing unit circularly collects low-speed signals of the display equipment end and sends the low-speed signals to the source end through the DP transmitting end module. According to the utility model discloses an embodiment, but time division multiplex unit is to low-speed signal's transmission order random arrangement.

In the DP receiving end module, the channel coding uses improved Manchester coding communication, so that normal communication can be realized without completely synchronizing clock signals of the DP transmitting end module and the DP receiving end module.

In the DP receiving end module, a receiving circuit receives signals in a channel, and the DP receiving end module has a local clock, so after receiving the signals, the synchronization unit carries out bit synchronization and frame synchronization on the received signals.

In the DP receiving end module, an AUX decoding and converting unit analyzes AUX + and AUX-signals of a display device end, a DDC decoding and converting unit analyzes SDA and SCL signals of the display device end, and a CEC decoding and forwarding unit analyzes CEC signals of the display device end.

The system comprises an AUX decoding and converting unit, a DDC decoding and converting unit and a CEC decoding and forwarding unit, wherein a local clock is used as an interval, a low-speed signal of a display equipment end is converted in real time, and meanwhile, the actual communication direction of a state machine control signal is analyzed through a real-time running protocol.

And the DP receiving end module analyzes the CONFIG signal of the display equipment end, and selects a DP or HDMI or DVI mode for subsequent channels to communicate according to the CONFIG signal. And the DP and DP + + ports have better compatibility with some DP protocol conversion interfaces.

According to the utility model discloses an in the embodiment, in the DDP receiving end module, the CONFIG analysis unit is according to the CONFIG1 signal of the level of display device end CONFIG1 foot and the source end that transmits from the light path, judgement communication protocol. For example, if the level of the CONFIG1 pin and the CONFIG1 signal from the source end transmitted from the optical path are both DP communication, the CONFIG analysis result indicates that DP communication is performed. And the level of the CONFIG1 pin and the CONFIG1 signal of the source end transmitted from the optical path are both HDMI and DVI communication, and the CONFIG analysis result is displayed to carry out HDMI/DVI communication.

In the DP receiving end module, if the CONFIG analysis result shows that DP communication is performed,

the AUX decoding and converting unit analyzes AUX + and AUX-signals of the display end in real time, and the protocol switching unit selects AUX + and AUX-signal transmission.

In the DP receiving end module, if the CONFIG analysis result shows that the HDMI/DVI communication is performed,

the DDC decoding and converting unit analyzes SDA and SCL signals of the display end in real time, and the protocol switching unit selects the SDA and SCL signals for transmission.

In the DP receiving end module, the DDC decoding and forwarding unit monitors the levels of the SDA and SCL signal lines in real time, and when it is monitored that a clock extension and Read Request (a Read Request, a function of actively pulling down SDA signals by the display device to Request the source device to Read its flag bit) event occurs at the display end of the device, the DDC decoding and forwarding unit can forward the Request to the HDMI transmitting end module in time, so as to notify the source device to perform corresponding operations.

A detailed explanation is given above of the structures of the DP transmitting side module and the DP receiving side module. The following is to the utility model discloses the working process of the analytic unit in DP transmitting terminal module and the DP receiving terminal module gives the explanation.

In the sending end module, if the CONFIG analysis result shows that HDMI/DVI communication is performed, the DDC decoding and conversion unit in the DP sending end module analyzes the SDA and SCL signals of the source end in real time, and feeds back ACK (Acknowledge character) and read data of the display device end to the source end in time. The DDC decoding and converting unit supports single read-write or continuous read-write operation of any I2C device address, and supports pulling down a source terminal SCL pin to inform a source terminal device of clock extension when a DP receiving terminal module sends a clock extension signal. When a DP receiving end module sends a Read Request signal, the SDA pin of the source end is pulled down to inform the source end equipment of the Request, and the DDC communication to the A8 address is requested to be initiated.

The DDC decoding and forwarding unit uses a DDC Slave state machine which runs in real time, and according to the communication state updated at the same time when the communication signal is forwarded in real time by communication sent by a host I2C (Inter-Integrated Circuit, two-wire serial bus), the DDC Slave state machine (Slave of the DDC protocol) can analyze whether the host I2C waits for an ACK signal of the Slave I2C or waits for reading data in real time, so that the IO communication direction can be switched to forward the signal received from the I2C to the host I2C in time, and the real-time I2C communication forwarding is realized. For example, the DDC Slave state machine resolves the master I2C in real time, the master I2C is waiting for ACK signal from I2C or waiting for data to be read, and switches IO communication direction to forward the signal received from I2C to the master I2C in time, so as to implement real-time I2C communication forwarding.

The DDC decode and forward unit may also resolve the clock stretch and Read Request instructions from the signal from I2C and control the SDA and SCL pins to forward both requests.

And when the DP transmitting terminal module is in an HDMI and DVI communication mode, the CEC decoding and forwarding unit analyzes the CEC signal of the source terminal and forwards the CEC signal to the display equipment terminal. The utility model discloses in every node all have local CEC arbitration unit, every node carries out local arbitration. After the arbitration fails, the original communication direction is switched, so the CEC communication with the arbitration failure is not transmitted any more, otherwise, the CEC communication is transmitted continuously in a Flooding broadcast mode.

As shown in fig. 3, the structure of the DDC decoding and forwarding unit of the DP receiving end module of the present invention is schematically illustrated.

In the receiving end module, if the CONFIG analysis result shows that HDMI and DVI communication is carried out, DDC decoding and converting units in the DP transmitting end module analyze SDA and SCL signals of the display equipment end in real time, and timely feed back ACK and read data of the source end to the display equipment end. The DDC decoding and converting unit supports single read-write or continuous read-write operation of any I2C device address, and supports that when a clock extension signal is sent by the DP transmitting terminal module, the pin of the display device terminal SCL is pulled down to inform the display device terminal device of clock extension. And when the DP transmitting terminal module sends a Read Request signal, pulling down the SDA pin at the display equipment terminal to inform the display equipment terminal equipment of requesting to initiate DDC communication to the A8 address.

The DDC decoding and converting unit uses a DDC Slave state machine which runs in real time, the DDC Slave state machine updates the communication state while transmitting the communication signal in real time according to the communication sent by the master I2C, and the DDC Slave state machine analyzes whether the Slave I2C waits for the ACK signal of the master I2C or waits for reading data in real time, so that the direction of IO communication can be switched to transmit the signal received by the master I2C to the Slave I2C in time, and the real-time I2C communication transmission is realized. For example, the DDC Slave state machine parses the Slave I2C in real time, and the Slave I2C is waiting for the ACK signal of the master I2C or waiting for reading data, and switches the IO communication direction to forward the signal received by the master I2C to the Slave I2C in time, thereby implementing real-time I2C communication forwarding.

The DDC decoding unit can also resolve the instructions of clock extension and Read Request according to the signal sent by the main I2C, and control SDA and SCL pins to forward the two requests.

When the DP receiving end module is in the HDMI/DVI communication mode, the CEC decoding and forwarding unit analyzes a CEC signal at the display device end and forwards the CEC signal to the source end. The utility model discloses every node all has local CEC arbitration unit, and every node carries out local arbitration. After the arbitration fails, the original communication direction is switched, so the CEC communication with the arbitration failure is not transmitted any more, otherwise, the CEC communication is transmitted continuously in a Flooding broadcast mode.

In the sending end module, if the CONFIG analysis result shows that DP communication is carried out, in the DP sending end module, an AUX decoding and converting unit analyzes AUX and AUX-signals of the source end in real time.

During AUX signal analysis, signal amplification and signal validity detection are carried out, and the analysis result is an AUX differential subtraction and amplified signal, namely an AUX valid signal. An AUX valid signal of 0 indicates that the input signal is in an idle state and there is no AUX communication. An AUX valid signal of 1 indicates that AUX communication is in progress. The AUX decoding and converting unit analyzes signals of local AUX and AUX valid and AUX valid signals transmitted from an opposite terminal (display equipment terminal) to obtain the transmission state of the AUX signals so as to determine the communication direction of the AUX.

In the receiving end module, if the CONFIG analysis result shows that DP communication is performed, in the DP receiving end module, the AUX decoding and forwarding unit analyzes the AUX and AUX-signals of the display device end in real time.

During AUX signal analysis, signal amplification and signal validity detection are carried out, and the analysis result is an AUX differential subtraction and amplified signal, namely an AUX valid signal. An AUX valid signal of 0 indicates that the input signal is in an idle state and there is no AUX communication. An AUX valid signal of 1 indicates that AUX communication is in progress. The AUX decoding and converting unit obtains the transmission state of the AUX signal by analyzing local AUX and AUX valid and AUX valid signals transmitted from an opposite end (source end) so as to determine the communication direction of the AUX.

The utility model discloses signal amplification has been realized to the output of AUX signal to support the AUX signal that the driving force output that a accords with the agreement level when exporting.

According to the utility model discloses an embodiment, the time division multiplex unit in the DP transmitting terminal module sends low-speed signal in multiplexing to a channel with time division multiplex's mode. The time division multiplexing unit in the DP receiving end module multiplexes the low-speed signals into one channel in a time division multiplexing mode to be transmitted.

According to the utility model discloses an embodiment, the channel coding unit in the DP transmitting terminal module carries out special coding to the information after time division multiplex. The channel coding unit in the DP receive end block specially encodes the time-division multiplexed information.

According to the utility model discloses an embodiment, the synchronization unit in the DP transmitting terminal module is used for carrying out bit synchronization and frame synchronization with the signal that the receiving element sent over and local clock. And the synchronization unit in the DP receiving end module is used for carrying out bit synchronization and frame synchronization on the signals sent by the receiving unit and a local clock.

According to the utility model discloses an embodiment, the time division multiplex unit that separates in the DP transmitting terminal module is used for demultiplexing received signal for low-speed signal output to the source end interface. And the time division demultiplexing unit in the DP receiving end module is used for demultiplexing the received signals into low-speed signals and outputting the low-speed signals to the interface of the display equipment.

According to the utility model discloses an embodiment, the transmitting circuit in the DP transmitting terminal module is used for converting the signal after the code to the signal that can transmit in communication channel. The transmitting circuit in the DP receiving end module is used to convert the encoded signal into a signal that can be transmitted in a communication channel.

According to the utility model discloses an embodiment, receiving circuit in the DP transmitting terminal module is arranged in converting received signal in the channel into the convenient subsequent processing of signal of specific level standard. The receiving circuit in the DP receiving end module is used to convert the signal received in the channel into a signal with a specific level standard for facilitating subsequent processing.

According to the utility model discloses an embodiment, the power supply of DP transmitting terminal module can be selected and is provided by the source end or external input power supply provides. The power supply of the DP receiving end module can be provided by the display end of the equipment or an external input power supply. The utility model discloses in contained the support to the HPD signal, can both correctly reflect the plug state of cable under the circumstances of the outer module power supply of DP receiving terminal or display device power supply.

According to the embodiment of the present invention, the line speed forwarding method of the present invention is not limited to the specific I2C address, and therefore, the present invention is applicable to reading of EDID signals, HDCP communication and SCDC communication. Compatibility can be achieved even for 128I 2C addresses from 0x00 to 0x 7F.

According to the utility model discloses an embodiment, the utility model discloses contained the processing to CEC signal arbitration, with the bus arbitration method in the CEC monobus communication, transplanted to light transmission or these point-to-point communications of wireless transmission in, used the method of local arbitration and arbitration result route, mapped the bus communication of CEC to the route communication in the point-to-point communication.

Fig. 6 is a schematic diagram of a circuit and high-speed signal forwarding combination according to another embodiment of the present invention. In this embodiment, use the utility model discloses low-speed signal line speed repeater circuit is integrated with high-speed laser instrument drive circuit and high-speed transimpedance amplifier circuit, realizes integrated chip. Chip On Board (Chip On Board) package integration is performed On a Chip VCSEL (Vertical Cavity Surface Emitting Laser) Laser and a photodetector On a designed PCB (Printed Circuit Board), so that the PCB system forms two active interfaces of a DP, DP + + optical fiber cable. The lens and the multimode optical fiber are connected with the two ports to form the DP optical fiber active cable, so that the high-speed audio and video data transmission between DP1.2 and DP1.4 protocol devices is realized by the cable at low cost.

Fig. 7 shows a schematic diagram of the circuit DP receiving end module connected to the HDMI protocol conversion interface according to another embodiment of the present invention. In this embodiment, use the utility model provides a DP optic fibre active cable is realized to the circuit, connects DP and HDMI's protocol conversion interface again at the DP receiving terminal, and the 100k resistance of CONFIG1 signal is pulled up in protocol conversion interface. The utility model discloses the demand of the active cable recognizable protocol switching of DP optic fibre of realization, with this information transmission to the DP transmitting end CONFIG1 interface on, inform the source end (the source end supports DP + +) to carry out SDA, SCL, CEC's low-speed communication to realize the audio and video transmission of the source equipment of DP + + to the display device of HDMI.

Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

Claims

1. A circuit compatible with DP, DP + + protocol low-speed signal carries on the line speed and transmits, characterized by that, the said circuit includes DP transmitting end module and DP receiving end module;

and the analysis module of the DP transmitting end module and the analysis module of the DP receiving end module reasonably switch the IO direction according to the actual communication state, so that the low-delay bidirectional communication is realized.

2. The circuit of claim 1, wherein the DP transmission side module comprises an AUX decoding and forwarding unit, a DDC decoding and forwarding unit, a CONFIG parsing unit, a protocol switching unit, a CEC decoding and forwarding unit, a CEC arbitration unit, a time division multiplexing unit, a channel coding unit, a synchronization unit, a time division multiplexing unit, a transmission circuit, and a reception circuit.

3. The circuit of claim 1, wherein the DP receiving module comprises an AUX decoding and forwarding unit, a DDC decoding and forwarding unit, a CONFIG parsing unit, a protocol switching unit, a CEC decoding and forwarding unit, a CEC arbitration unit, a time division multiplexing unit, a channel coding unit, a synchronization unit, a time division multiplexing unit, a transmission circuit, and a reception circuit.

4. The circuit of claim 3, wherein in the DP transmitting end module, the CONFIG parsing unit decides the communication protocol according to the level of a source terminal CONFIG1 pin and a CONFIG1 signal of the display device terminal transmitted from the optical path.

5. The circuit of claim 4, wherein in the DP transmitting end module, if the CONFIG parsing result shows that DP communication is performed,

the AUX decoding and forwarding unit analyzes AUX + and AUX-signals at the source end in real time, and the protocol switching unit selects AUX + and AUX-signal transmission.

6. The circuit of claim 4, wherein in the DP transmitting end module, if the CONFIG parsing result shows HDMI, DVI communication,

7. The circuit of claim 3, wherein in the DP receiving end module, the CONFIG parsing unit decides the communication protocol according to the level of a display device terminal CONFIG1 pin and a source terminal CONFIG1 signal transmitted from the optical path.

8. The circuit of claim 7, wherein in the DP receiving end module, if the CONFIG parsing result indicates that DP communication is performed,

9. The circuit of claim 7, wherein in the DP receiver module, if the CONFIG parsing result indicates HDMI/DVI communication,

then the DDC decoding and forwarding unit analyzes SDA and SCL signals of the display equipment end in real time, and the protocol switching unit selects the SDA and SCL signals for transmission.