CN101090353A

CN101090353A - LED display screen data communication equipment and method based on embedded Ethernet technology

Info

Publication number: CN101090353A
Application number: CNA2007100353751A
Authority: CN
Inventors: 邓宏贵; 李志坚; 吴让亮; 方远孟
Original assignee: Central South University
Current assignee: Central South University
Priority date: 2007-07-17
Filing date: 2007-07-17
Publication date: 2007-12-19

Abstract

This invention relates to a LED display data communication device and a method based on an embedded Ethernet technology, in which, the LED screen is composed of several independent display modules controlled by corresponding control modules, each of the control modules is set with an Ethernet interface to connect the control module to an ordinary Ethernet by a central collector in a star-like topological structure, and the computer is cut-in from the other terminal of the Ethernet to realize data transmission between the computer and the screen in terms of TCP/IP protocol.

Description

LED display data communications equipment and method based on the embedded ethernet technology

Technical field

The present invention relates generally to multimedia technology field, particularly the photoelectric display technical field.

Background technology

At present, the application of big screen LED display screen is very extensive, and the key technical problem of its development is following two aspects, and the first, its display effect of how further taking on a new look makes it can both show best color effect in various application scenarios.The second, how to improve its antijamming capability, strengthen its job stability.Big screen LED display screen poor anti jamming capability, the failure rate height, its reason is many-sided.The instability of transfer of data is one of them main cause, the general screen area of LED display is bigger, be subjected to the restriction of making sheet and processing technology, usually all adopt modular mode design, promptly at first design each display module, according to actual conditions each display module is made up when using then.Module often adopts common winding displacement to be connected with connecting line between the module, because whole LED display screen display module is many more, line between the module also can be many more, circuit connects also can be complicated more, like this, out of order probability also can be big more during entire display screen work, and operation stability is also poor more, is subject to more disturb.

And at present, 10,000,000,100,000,000 even the fast development of gigabit Ethernet network, make that the communication speed of Ethernet is more and more faster, and advantages such as the wiring that it had is simple, the error rate is low, networking agreement maturation, can satisfy the needs of LED display data communication fully.

Summary of the invention

The purpose of this invention is to provide a kind of LED display data communications method.

The present invention is the high speed data transfer that the embedded ethernet technology is applied to LED display, the video data that computer is obtained sends to the Hub module of display screen by network interface card, by Hub data are distributed to each display screen control module then, the control of display screen control module is from the Ethernet interface reading of data, and resolve by ICP/IP protocol, simultaneously, the data in real time that extracts is presented on the LED screen, has finished the data transmission procedure of LED display.

The present invention mainly comprises main control system, display screen Hub module, display screen display control module and display module.Main control system can be other a network-termination device of a computer or, and it directly links to each other with display screen Hub module, mainly is responsible for display screen and shows needed data are provided.Main control system must have the Ethernet interface that meets the IEEE802.3 standard, and main control system is issued display screen Hub module by this interface data.Display screen Hub module links to each other with display control module with main control system, and main being responsible for receives the Ethernet data that main control system transmits, and the data branch is mail to each display control module.All adopt general twisted-pair power cable to be connected between main control system and the display screen Hub module, display screen Hub module and each display screen control module, communication protocol is all adopted ICP/IP protocol.The display screen display control module is a core content of the present invention, it directly links to each other with display module, mainly comprise a FPGA and an Ethernet interface, except that realizing that the control display module is normal and showing, FPGA also finish initialization setting, control Ethernet interface to Ethernet interface detect receive data, by standard agreement to data resolve, function such as update displayed module displaying contents.

Adopt star topology to carry out networking between main control system of the present invention, the display control module, thereby realize high speed, the stable transfer of data by display screen Hub module.

Display control module of the present invention mainly comprises FPGA, network card chip, impedance transformer and RJ45 interface, as shown in Figure 1.FPGA then enters the cycle detection state after finishing initialization to network card chip, and constantly whether the cycle detection network card chip has packet to receive.Specifically be by FPGA being programmed, realizing at state machine of the inner realization of FPGA.

FPGA internal state machine of the present invention mainly divides 5 states, is respectively reset mode, time-delay state, init state, data receiving state and data processing state.Each state transitions situation as shown in Figure 2.Particular content is: a. reset mode, this state draw network card chip reset pin RSTDRV exactly and are high level, and network card chip is resetted.B. the state of delaying time, because the network interface card reset operation needs several milliseconds time at least, thereby, after the network interface card reset signal is sent, need wait for a period of time, guarantee that network interface card is finished to reset.Concrete time-delay adopts the mode of trigger to carry out, and delay time length can be regulated by setting the counter maximum.C. init state, this state is finished the initialization operation to network card chip, be specially: define two initialization constant tables, one of them is the initialization register address list, another is pairing initialization data tabulation, address and data are one-to-one relationship in these two tables, and in fact whole initialization procedure is exactly to read two initialization address and data in the table successively, and they are write the process of network card chip one by one.D. cycle detection state, after initialization is finished, the current page register CURR and the boundary register BNRY of network card chip are changed to equal value, when network card chip is received data, current page register CURR just can increase automatically, therefore, only need the FPGA circulation to read the value of BNRY register and CURR register, when the value that detects the BNRY register is not equal to CURR, FPGA just can be from network card chip reading corresponding data, and make the BNRY register add 1 simultaneously, equal the CURR register once more up to it.E. data processing state, when detect receive new packet after, FPGA reads this packet from network card chip, and, confirm whether be this machine desired data bag according to source, the purpose IP address of IP protocal analysis notebook data bag, if, then proceed application layer and resolve, otherwise, this bag abandoned.

The present invention can significantly strengthen the LED display antijamming capability, improves the service behaviour of LED display.

Description of drawings

Fig. 1 LED display network interface hardware structural representation;

Fig. 2 is the state diagram of FPGA control network interface card software design;

Fig. 3 is a LED display overall structure schematic diagram;

Fig. 4 is a display control program software design flow chart.

Below the present invention is described in detail.

Embodiment

The present invention is that the LED display data communications method is specifically implemented by structure shown in the accompanying drawing 3: with the Hub modular design in LED display large-screen back, each display control module of LED display directly is connected into Hub by general twisted-pair power cable, and entire display screen only links to each other with the external control main frame by a twisted-pair feeder of drawing from the Hub module.

Main control system will be issued Ethernet by network interface card after the data encapsulation after gathering video data, and specific implementation is that the socket of Windwos operating system is programmed.Because the IP agreement stipulates that each IP packet size can not surpass 1514 bytes, therefore, can take to become the form of packet to send data encapsulation to be sent in batches, each packet encapsulation 1024 byte data can meet the demands.Packet needs to add the IP head in encapsulation process, and wherein most crucial is the purpose IP address and the target MAC (Media Access Control) address of packet.Concrete definite method is: the front three of purpose IP address must be identical with the front three of this machine IP address, purpose IP address and MAC Address are all determined according to the display module that notebook data will mail to, determine and the IP address of each display module and MAC Address are unique when design, and, the corresponding relation of each display module IP address and MAC Address is added in the IP map addresses buffer memory of main control system, like this, main control system just adds the IP head automatically according to the mapping relations in the IP map addresses buffer memory, with data encapsulation.

The display control module of display screen is mainly finished the Data Receiving scan control, Data Receiving adopts RTL8019 as interface chip, RTL8019 be a peripheral interface producing of Realtek company simple, integrate Fast Ethernet MAC layer, physical layer and transceiver, cheap network interface chip.In the design, saved the ROM and the EEPROM of RTL8019 outside, initialization of register parameter required when powering on is configured by FPGA.

The transmitting-receiving circuit of RTL8019 is a pair of differential lines, is to link to each other with netting twine behind 1: 1 the Ethernet transformer through no-load voltage ratio, and the main effect of Ethernet transformer is impedance matching, signal shaping, isolation network, the noise of filtering network and equipment.

With FPGA the RESDRV of RTL8019AS is carried out reset operation.RSTDRV is that high level is effective, resets reliably in order to make, and applies a high level about 1ms for this pin and just can reset.Reseting procedure also can be carried out some other operations, also needs the regular hour, therefore for it is resetted fully, has delayed time 900 milliseconds in program.

FPGA to RTL8019 reset finish after, next just carry out initialization operation, initialization mainly is that physical address, mode of operation and relevant register initial value are set, each Ethernet interface all designs unique IP address and physical address.Carry out the network monitoring state then, check and whether receive new data.If do not receive, the then continuous cycle detection of FPGA if there are new data to arrive, is then read in buffering area with these data, and the data of receiving are handled by flow chart shown in Figure 4: FPGA analyzes packet, judgement is ARP bag or IP bag, if the ARP bag is then directly replied, if IP bag, then continue to judge whether bag, handle, continue to enter the cycle detection state after finishing if then this packet is separated to receive accordingly into UDP.

Claims

1. LED display data communications equipment, it is characterized in that: comprise main control system, display screen Hub module, display screen display control module and display module, each design of the control module of LED display has an Ethernet interface, by FPGA display screen is controlled, comprise initialization setting to Ethernet interface, the control Ethernet interface detects and receives data, by standard agreement data are resolved, update displayed module displaying contents, each display module of display screen directly by access network based on ethernet network behind the hub, is realized the real-time Transmission of data between main frame and display screen.

2. LED display data communications equipment according to claim 1 is characterized in that: the separate and respectively corresponding well-determined physical address of described Ethernet interface.

3. method of utilizing the described LED display data communications equipment of claim 1 to carry out communication, it is characterized in that: obtain the video data of required demonstration by main frame earlier, by network interface card data are mail to the Hub module of display screen again, by Hub data are distributed to each control module of display screen then, by FPGA display screen is controlled, the display screen control module is extracted received data, resolve, data are transmitted with the form of IP bag on ethernet line, are shown by display module.