JP2004126252A - Led controller unit and led display device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To allow an LED display to be in a state in which normal operation of a transmission/reception circuit is possible, before data reception. <P>SOLUTION: An LED controller using packet data communication between LED display units or between an LED display unit and an LED display unit controller has a detection means for detecting a reset signal added to the head of packet data being a leading part of reception data and a reset means for initializing the transmission/reception circuit in a communication part on the basis of the signal from the detection means. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an LED control device and an LED display using packet data communication.
[0002]
[Prior art]
In recent years, high-performance red, green and blue LEDs have been developed, and full-color LED display has become possible. Among large display devices, LED display devices that utilize the features of LEDs such as high brightness, long life, and light weight are rapidly spreading. In addition, their uses are diversifying, and there is a demand for a system that can flexibly handle various applications such as large televisions, advertisements, traffic information, stereoscopic displays, and lighting.
[0003]
The displays that use these LEDs range from large outdoor displays such as for billboards to medium and small screen sizes for semi-indoors such as platforms, depending on the application and location. Various displays with different pixel pitches have been used. Also, the vertical / horizontal screen ratio (aspect ratio) tends to change. When high-definition video such as HDTV is displayed on an LED, the amount of video data increases and the display panel becomes larger. Must also respond. Also, under the advanced information network, it is required that the display is connected to such a communication infrastructure and can handle display control, maintenance, etc. by remote operation.
[0004]
In such a display, for example, LEDs of about 16 dots × 16 dots are arranged in a matrix and modularized as a single LED unit, and the LED unit is arranged according to the screen size, vertical / horizontal aspect ratio, and the like. Concatenated in a matrix. FIG. 1 shows an LED display 801 as a configuration example. A plurality of distributors 804 connected to the controller 803 are arranged for each row of the LED units 802 and supply video data for display and various control signals to the LED units 802.
[0005]
The control signal 820 includes, for example, a video data synchronization clock, a horizontal synchronization signal, a vertical synchronization signal, a blank signal, a gradation reference signal, a video data latch signal, and the like. It supplies to each LED unit 802 via 804. The display full-color video data 810 transmitted from the distributor 804 to each LED unit 802 requires at least RGB (red, green, blue) video data, and the bit width of the video data is determined according to the gradation resolution.
[0006]
For example, when displaying with 256 gradations per color, an 8-bit video data bus is required for three colors. These video data are supplied to the LED unit 802 by time-dividing the number of LED units × the number of display dots. The video data 810 is bit-shifted by the shift register circuit 805 in each LED unit 802, the data is latched when a predetermined number of data is supplied, and the captured video data is displayed as the display video data 810. it can.
[0007]
[Problems to be solved by the invention]
However, such an LED display device transmits display video data 810 between the controller 803, the distributor 804, and the LED unit 802 via a parallel bus as a signal interface, and supplies synchronized clocks and various control signals 820 synchronized therewith. Yes. Therefore, there has been a problem that the number of signal lines increases as the LED display device becomes higher definition or larger. In particular, at present, when the display screen tends to be larger and the number of LED units increases, the signal lines increase and become longer, and the gray scale reference signal, the deterioration of the pulse width of the video data synchronization clock, and the effects on noise are serious problems. Become.
[0008]
In order to support the HDTV specification, the aspect ratio of the screen changes, and it becomes necessary to further increase the number of connected LED units, and the transfer rate of video data must be increased accordingly. As the number of LED units connected increases, the pulse deterioration of each signal increases, and there is also a problem that the input / output timing between the video data and the synchronous clock becomes particularly difficult.
[0009]
Further, the level of image quality required for image display of LED display devices has been increasing year by year, and along with the miniaturization of LEDs, the technical development of LED displays capable of fine display has become an urgent task. In order to realize fine display of video, it is necessary to increase the gradation resolution. Specifically, it is necessary to change the bus specification such as changing the display video data bus width from 8 bits to 10 bits. In order to realize fine display, it is necessary to reduce the size of the LED and reduce the dot pitch width. When the dot pitch is reduced, the LED unit size is reduced proportionally. Therefore, there is a problem that the ratio of the mounting area of components such as connectors increases due to the increase in the video data bus width.
[0010]
In addition, the LED display device cannot communicate with a plurality of LED display devices having different display gradations or different numbers of pixels per LED display device by a common communication method.
In other words, when packet data is received, there is a problem that normal reception is not possible unless the transmission / reception circuit performs normal operation before data reception, and not all data that is sent is sent in a normal format. For example, if illegal data is received due to noise or power fluctuation, and the data is stored in the internal storage means, the malfunction of the part that reads the data and controls the LED driver IC etc. There was a problem that caused it. Furthermore, if incorrect data is output as transmission data as it is, there is a problem in that the next connected LED unit is also affected.
[0011]
[Patent Document 1]
WO 02/03365
[0012]
An object of the present invention is to make it possible to perform normal operation of a transmission / reception circuit before receiving data, and to prevent data with illegal contents from being stored in an internal storage means.
[0013]
[Means for Solving the Problems]
The LED control device according to claim 5 of the present invention is the LED control device using packet data communication between the LED display units or between the LED display unit and the LED display unit controller. The LED control device includes a detection unit that detects a reset signal added to the head of data, and a reset unit that initializes a transmission / reception circuit in the communication unit based on a signal from the detection unit. As a result, the transmission / reception circuit can always be reset before data reception, and smooth data transmission / reception can be performed.
[0014]
The LED control device according to claim 2 of the present invention is an LED unit internal storage unit that stores received data based on a signal from the detection unit, and a reception unit that generates a control signal for controlling the LED unit internal storage unit. An LED control device having data latch means and means for communicating packet data to a transmission circuit. With this configuration, it is possible to restore the receiving circuit to a state in which normal operation can be performed before data reception. In addition, data with illegal contents is not stored in the internal storage means, and reliability is improved.
[0015]
The LED control device according to claim 3 of the present invention is an LED control device comprising an additional circuit for transmitting the transmission circuit by adding a reset signal added to the head of the packet. Thereby, highly reliable communication can be performed between LED units or between an LED unit controller and an LED unit.
[0016]
The LED display according to claim 4 of the present invention is an LED display using packet data communication between LED display units and between an LED display unit and an LED display unit controller. It is an LED display having detection means for detecting a reset signal added to the head and reset means for initializing a transmission / reception circuit in the communication unit based on a signal from the detection means. As a result, the transmission / reception circuit can always be reset before data reception, and smooth data transmission / reception can be performed.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, fixed data SOP (Start of Packet: signal added to the head of packet data) having an arbitrary content is used at the head of the packet data format. A circuit capable of detecting SOP is prepared inside the packet data receiving circuit, and an SOP reset signal is output every time SOP is detected, and immediately after that, an SOP flag is raised. The SOP reset signal is input to a reset circuit of a main circuit in the receiving circuit and a main circuit of the transmitting circuit, and is initialized by a reset unit. As a result, most of the receiving circuit and the transmitting circuit are reset (initialized) immediately after receiving the packet data to which the SOP is added, so that the receiving circuit and the transmitting circuit can operate normally before receiving the data. Can do.
[0018]
Further, an SOP addition circuit is added to the transmission circuit so that all transmission data is transmitted with the SOP added. As a result, the LED unit to be transmitted can be reset before receiving data.
Further, a reception data selection circuit is prepared so that reception data is not stored in the internal storage means unless the SOP flag is raised. In other words, control signals and data for loading into the internal storage means, control signals for performing LED lighting display, and the like are not generated at all.
[0019]
A block diagram of the circuit of the present invention is shown in FIG. 1, and a timing chart is shown in FIG. When received packet data is input from the outside to the receiving circuit in the communication unit, first, serial data is converted into parallel data (data 1) by a serial-parallel conversion circuit. While this data is being received, the reception state counter in FIG. 1 operates so that the current reception state can be recognized. For example, in FIG. 2, when the upper reception state is “3” and the lower reception state is “C”, it means that DATA1 has been received, or the upper reception state is “7” and the lower reception state is “C”. In this case, it can be seen from the value of the reception state counter that DATA2 has been received. And what kind of internal operation is performed when certain data is received in a certain state is specified. When the above reception upper state is “3” and the reception lower state is “C” When DATA1 is received, an internal operation corresponding to the data, for example, an operation A is performed. Similarly, when the upper reception state is “7” and the lower reception state is “C”, when DATA2 is received, for example, operation B is performed.
[0020]
On the other hand, the transmission circuit also has the transmission state counter in FIG. 1, and operates the transmission state counter when a transmission flag is raised from the reception circuit. Then, in a lower state having a certain transmission upper state, predetermined data is transmitted. For example, when the upper transmission state in FIG. 2 is “1” and the lower transmission state is “FC”, transmission of data 1 is started, or when the upper transmission state is “3” and the lower transmission state is “FC”. Starts sending data 2.
[0021]
In the circuit according to the present invention, when data 1 is input at a certain timing, that is, when the reception upper state in FIG. 2 is “0” and the reception lower state is “1”, the SOP is received. Recognizing that the SOP detection circuit has received SOP, an SOP reset signal is output. As shown in FIG. 2, the SOP reset signal is a main part of a transmission / reception circuit such as a reception upper state, a reception end signal, an SOP flag, internal operations A, B, and C, a transmission flag, a transmission lower state, a transmission upper state, and a transmission end signal. Reset the important part. That is, most of the transmission / reception circuit can be reset immediately after detecting the SOP, and the reception circuit can be normally operated before the subsequent data reception. However, the serial-parallel conversion circuit and the circuit that receives the received data such as the lower reception state are not reset.
[0022]
When the data SOP at the head of the packet data of data 1 is detected by the detection means (hereinafter also referred to as SOP detection circuit), the SOP flag is raised, and if it is not detected, the SOP packet is not raised. Data 1 enters the received data selection circuit. If the SOP flag is raised here, only the received data portion of data 1 during that period is extracted (data 2). If not, the received data is not extracted at all. I will not. That is, if there is no SOP at the head of the packet data, the packet data is ignored and is not handled as data. Even if the same data as the SOP other than the first packet is input, the SOP detection circuit does not recognize the SOP (no SOP flag is raised), and if the flag is raised, it is handled as normal received data.
[0023]
Data 2 is temporarily held by the reception data latch means and then sent to the transmission unit (data 3). The data 3 sent to the transmission unit becomes data 4 with the SOP added again at the head by the SOP addition circuit, and is inputted to the parallel-serial conversion circuit and then outputted to the outside as serial data (transmission packet data). Is done.
[0024]
If the data 2 cannot be extracted because the SOP flag is not raised in the reception data selection circuit, the reception data is prevented from being stored in the internal storage means. In other words, control signals and data for loading into the internal storage means, control signals for performing LED lighting display, and the like are not generated at all.
[0025]
【Example】
FIG. 3 shows an embodiment in which the actual design and operation are performed. An LED unit controller and LED units connected in a plurality of stages (LED unit block) are configured, and full duplex bidirectional packet communication is performed between the LED unit controller and the LED unit or between the LED units. The LED unit uses bi-directional communication, so the direction of the signal is not fixed, so there is no distinction between connector input and output (input / output is possible from either left or right), and the communication line between each unit is the shortest distance It is possible to connect with. As a result, signal waveform attenuation, radiation noise, and the like caused by the length of the communication distance can be minimized. Furthermore, since the number of signal lines is reduced, a differential transmission system (balanced transmission system) can be used, and radiation noise, communication distance, and communication speed can be improved. In this embodiment, balanced transmission method, unbalanced transmission method, or a mixture of them, for example, transmission from the controller by balanced transmission method, and conversion to unbalanced transmission method in front of the LED unit are also performed to confirm normal operation. It is carried out.
[0026]
The LED unit controller can individually send packet data to all LED units, and the display data packet is normally transmitted to all LED units at a period of 60 Hz. The received display data is sent to the storage device by the communication unit inside the LED drive circuit, which is mounted one by one in the LED unit. When the driver IC control circuit reads the data, display data is sent to the LED driver IC, and the LED lighting operation is started.
[0027]
The circuit of the present invention is composed of the inside of the receiving circuit of the communication unit, the inside of the transmitting circuit and its peripheral circuits in the LED driving circuit inside the LED unit. At this time, 16 bits of data “01001011110110100” is applied to all types of packet formats for the SOP at the head of the packet data to confirm normal operation. If this data length is too short, the probability that random received data such as noise will be taken in increases, and conversely if it is too long, the data transfer efficiency falls.
[0028]
【The invention's effect】
With the configuration of the present invention, it is possible to restore the receiving circuit to a state in which normal operation can be performed before data reception. In addition, data with illegal contents is not stored in the internal storage means, and reliability is improved.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram showing a circuit block of the present invention.
FIG. 2 is a timing chart for explaining the operation of the present invention.
FIG. 3 is a schematic block diagram according to an embodiment of the present invention.

Claims (4)

Detection means for detecting a reset signal added to the head of the packet data, which is the head portion of the received data, in the LED control apparatus using packet data communication between the LED display units or between the LED display unit and the LED display unit controller And an LED control device having a reset unit that initializes a transmission / reception circuit in the communication unit based on a signal from the detection unit. LED unit internal storage means for storing received data based on a signal from the detection means, reception data latch means for generating a control signal for controlling the LED unit internal storage means, and means for communicating packet data to a transmission circuit The LED control device according to claim 1. The LED control device according to claim 2, wherein the transmission circuit includes an additional circuit that adds and transmits a reset signal added to the head of packet data. In an LED display using packet data communication between LED display units and between LED display units and an LED display unit controller, detection means for detecting a reset signal added to the head of the packet data, which is the head portion of received data An LED display having reset means for initializing a transmission / reception circuit in the communication unit based on a signal from the detection means.

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