CN201514738U

CN201514738U - LED display screen

Info

Publication number: CN201514738U
Application number: CN200920187357XU
Authority: CN
Inventors: 王文杰
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-09-04
Filing date: 2009-09-04
Publication date: 2010-06-23
Anticipated expiration: 2019-09-04

Abstract

The utility model relates to an LED display screen, which is characterized by being provided with a control system consisting of a single chip microcomputer and a complex programmable logic device (CPLD) and comprising a signal receiving and processing module formed by the single chip microcomputer, a scanning and control module realized by the CPLD and an LED lattice driving module; the signal receiving and processing module receives lattice information which is sent by a PC and received by the single chip microcomputer through a serial port, makes corresponding information processing including character motion and refresh rate to the lattice information, carries out data communication with the CPLD by using an external bus interface and completes the display of the LED lattice scanning by the CPLD; the scanning and control module of the CPLD receives control information from the single chip microcomputer, reads the lattice information from a lattice character die storage, sends the lattice information to a display, scanning and driving circuit after serialization and simultaneously outputs the needed control signal; and the LED lattice driving module forms a larger LED display screen by an LED lattice screen unit through longitudinal or horizontal cascade. The LED display screen utilizes a site programmable logic device to arrange a main controller and can be convenient to arrange the whole display system.

Description

A kind of LED display

Technical field

The utility model relates to a kind of LED display, a kind of display screen that uses the high-brightness LED luminotron to constitute dot matrix of more specifically saying so.

Background technology

The LED dot matrix of middle and small scale shows that use is very extensive, when adopting Single-chip Controlling, needs a large amount of peripheral resource of expansion, and is not easy to expand, revises and safeguards.

The system programmable logical device has abundant I/O mouth and internal resource, and the programming of device and modification are also very convenient.System programmable technology (ISP-In System Programming) and system programmable family device are new technology and the new units that develops rapidly the nineties.Field programmable device ISP devices such as (FPGA and CPLD) need not programmable device, the programming external member of utilizing device manufacturer to provide, adopt from the top and under modular design method.Use principle figure or hardware description language methods such as (VHDL) is described the circuit logic relation, can be directly to being installed in the device programming on the Target Board.It easily learns, easy-to-use, simplified system design, reduced system scale, shorten the design cycle, reduced the production design cost.Thereby brought revolutionary variation for the design and the production of electronic product.

The LED dot matrix shows that the traditional approach of control is to adopt single-chip microcomputer or system's machine to realize as CPU, when the information of system's demonstration is many, because the input/output end port I/O of single-chip microcomputer is limited, adopts the cost of this mode to increase greatly, the design difficulty of the system and program also sharply increases; And when revising, changing display mode or expansion after system finishes, the place of required change is bigger, even might need redesign; In addition, to be shown as in the main system, the utilization factor of major functions such as the computing of single-chip microcomputer and control is very low, and the advantage of single-chip microcomputer can not get performance, is equivalent to the very big wasting of resources.

The utility model content

The utility model is for avoiding above-mentioned existing in prior technology weak point, a kind of LED display is provided, utilize field programmable logic device that master controller is set, select suitable device, utilize device abundant I/O mouth, internal logic and interconnection resources, employing from the top and under modular approach, whole display system is set easily.

The utility model technical solution problem adopts following technical scheme.

The circuit structure characteristics of the utility model LED display are:

Setting is by the control system that single-chip microcomputer and programmable logic device (CPLD) constitute, and comprises by single-chip microcomputer constituting scan control module and the LED dot matrix driver module that signal reception and processing module, programmable logic device (CPLD) are realized;

It is to receive the lattice information that PC sends here by single-chip microcomputer by serial ports that described signal receives with processing module, simultaneously lattice information is made and comprise that character moves with the corresponding information of refresh rate and handle, and utilize external bus interface and programmable logic device (CPLD) to carry out data communication, finish the demonstration of LED lattice scanning by described programmable logic device (CPLD);

The scan control module of described programmable logic device (CPLD) receives the control information from single-chip microcomputer, reads lattice information from the dot-matrix font storer, send the reading scan driving circuit after the serialization, exports required control signal simultaneously;

Described LED dot matrix driver module constitutes LED dot matrix screen unit by the LED dot matrix of 16*32, constitutes bigger LED display curtain with each LED dot matrix screen unit by vertical or horizontal cascade.

The circuit structure characteristics of the utility model LED display also are:

The version of dynamic scan is set in described LED dot matrix driver module, the LED basic display unit of each 16*32 is made of LED dot matrix screen unit, line scanning unit and column scan unit, described line scanning unit is the decoding scheme of the 4-16 that is made of two 74HC138, and each road output is with the indirect driving LED of field effect transistor of serial connection; Described column scan by be by the string with SPI interface-and conversion chip 74HC595 constitute, each LED basic display unit is by four 74HC595 chip cascades, its output directly drives 32 and is listed as LED.

Described single-chip microcomputer adopts the STC89C58 device, described programmable logic device (CPLD) adopts the EPM7128S device, between described single-chip microcomputer and programmable logic device (CPLD), be set to the bus communication mode, single-chip microcomputer passes through RD, W R, the multiplexing P0 mouth of data address, high address P2 mouth is connected with programmable logic device (CPLD), and single-chip microcomputer can pass through outer read/write instruction access programmable logic device (CPLD); Behind the Hanzi internal code that programmable logic device (CPLD) reception single-chip microcomputer transmits, this horizontal and vertical parity check code storehouse of search is to be put horizontal and vertical parity check code accordingly in the dot-matrix font storer externally, the point horizontal and vertical parity check code serial that will search then outputs to string-and conversion chip 74HC595, and the chip selection signal of synchronous shift pulse signal CLK, row decoding signal and LED lattice module is provided for dot matrix display screen simultaneously.

Compared with the prior art, the utility model beneficial effect is embodied in:

1, the utility model is realized data communication with single-chip microcomputer and CPLD device by bus mode, receive the lattice information that PC sends here by single-chip microcomputer, simultaneously lattice information is made and comprise that character moves with the corresponding information of refresh rate and handle, realize the quick scan control of LED dot matrix has been solved the common LED display screen and has been difficult to improve the scintillation effect that produces because of the excessive refresh rate of screen by CPLD.

2, the utlity model has high reliability, control system is simple, systems control division divides simply is provided with the high reliability of further having brought system, this also mainly is because the use of programmable logic device (CPLD), substitute the use of some DLC (digital logic circuit), reduce the number of elements of circuit, have the stability of several times than too much discrete device technology.

3, the utility model system adopts the blocking setting, the system line of making is intuitively easy, it is very easy that the installation of system, debugging and maintenance become, and the size of display screen body can be spliced adjustment as required, can conveniently organize structure LED dot matrix size according to the size of displaying contents.Can show Chinese and English character, figure and motion graphics etc. by programming Control.

4, the utility model is easy to safeguard, because system is simple, is very easy to maintenance, reduces maintenance cost.

Description of drawings

Fig. 1 constitutes block scheme for the utility model system.

Fig. 2 is the utility model LED display main control unit.

Fig. 3 is the utility model LED display driver element.

Below by embodiment, the utility model is described in further detail in conjunction with the accompanying drawings.

Embodiment

Referring to Fig. 1, the utility model system is made of three big modules: the scan control module of signal reception and processing module, CPLD and LED dot matrix driver module.It is to receive the lattice information that PC sends here by single-chip microcomputer by serial ports that signal receives with processing module, simultaneously lattice information is made and comprise that character moves with the corresponding information of refresh rate and handle, and utilize external bus interface and programmable logic device (CPLD) to carry out data communication, finish the demonstration of dot array data by programmable logic device (CPLD); The scan control module of programmable logic device (CPLD) receives the control information from single-chip microcomputer, reads lattice information from the dot-matrix font storer, send the reading scan driving circuit after the serialization, exports required control signal simultaneously.LED dot matrix driver module constitutes dot matrix screen unit by the LED dot matrix of 16*32, constitutes bigger LED display curtain with each dot matrix screen unit by vertical or horizontal cascade.

Figure 2 shows that present embodiment LED display main control unit, the scan control module of signal reception and processing module and CPLD is by Fig. 2 specific implementation.Signal receives with processing module and adopts single-chip microcomputer STC89C58 of STC Corporation and level transferring chip MAX232 to realize, MAX232 realizes mutual conversion between Transistor-Transistor Logic level and 232 level in conjunction with outer member, communicating by letter between realization STC89C58 and PC.MAX232 one end connects the serial line interface TXD of STC89C58, RXD; The other end connects the serial line interface of DB9, conveniently communicates by letter with PC by Serial Port Line.The external 11.0592MHZ crystal oscillator of STC89C58 makes things convenient for the baud rate setting of serial communication.STC89C58 receives the lattice information that PC sends here by serial ports, simultaneously lattice information is made comprising that character moves with the corresponding information of refresh rate and handling, and utilizes external bus interface to send these information to CPLD, is finished the demonstration of dot array data by CPLD.

The scan control module of CPLD adopts the EPM7128S chip of ALTERA company to realize that it has 128 logic macrocells, and logic gate number is 2500, has 100 pins, and 84 user I/O are wherein arranged.It adopts the 5V power supply, and convenient and other Transistor-Transistor Logic level chip interface is configured to its inside by VHDL language written program code by jtag interface.The active crystal oscillator of its external 50MHZ of global clock pin is for it provides global clock.EPM7128S adopts 21 I/O to be connected with STC89C58, and wherein 16 P0 and P2 mouths that are connected respectively to STC89C58 have been realized bus communication.2 WR and RD that are used to connect STC89C58 are used for read-write control, other three P1.0 that are connected respectively to STC89C58, and P1.1, P1.2 is used for the handshaking information between STC89C58 and EPM7128S.EPM7128S adopts 29 I/O to be connected with dot-matrix font storer SST39VF040, and SST39VF040 is the FLASH device of the 512K*8 of SST company, is used to store the lattice information of type matrix.EPM7128S adopts 22 I/O to be connected with LED dot matrix driver module, each LED display main control unit vertically can connect 8 LED dot matrix driver modules by J1-J8, A among the J1-J8 wherein, B, C is the decoded signal of 74HC138 in the LED dot matrix driver module, and G is the chip selection signal of 74HC138 in the LED dot matrix driver module; CLK among the J1-J8, SI are serial clock and the serial data of 74HC595 in the LED dot matrix driver module; CS1-CS8 is respectively row sheet choosing in the LED dot matrix driver module among the J1-J8, and CS11-CS88 is row sheet choosing in the LED dot matrix driver module, and all effective as CS1 and CS11, the LED dot matrix driver module that promptly J1 connected is selected, is used to show lattice information.Can be by above circuit CPLD by the control information and the lattice information of bus interface reception from single-chip microcomputer, from the dot-matrix font storer, read lattice information, send the reading scan driving circuit after the serialization, export the clock signal of LED dot matrix driver module simultaneously, decoded signal and chip selection signal, the frequency period of having set the LED dot matrix is carried out dynamic scan.Characteristics such as it is fast that EPM7128S has sweep velocity, and time-delay is short have overcome single-chip microcomputer and have caused the scintillation effect that produces when the large screen display owing to transfer rate slowly.

Referring to Fig. 3, the LED dot matrix driver module in the present embodiment constitutes dot matrix screen unit by the LED dot matrix of 16*32, constitutes bigger LED display curtain with each dot matrix screen unit by vertical or horizontal cascade.Raise the efficiency for energy-conservation, system adopts dynamic scan mode.Each 16*32LED display unit is by the LED dot matrix, line scanning and column scan constitute, wherein line scanning is considered that directly driving LED is exported in the decoding of 74HC138, and is gone driving LED indirectly at every road output serial connection field effect transistor FDS4953 by the decoding scheme that 2 74HC138 constitute a 4-16; Column scan is finished by 74HC595, and 74HC595 is string with SPI interface-and conversion chip, and each basic led display unit is by 4 74HC595 chip cascades, and its output directly drives 32 and is listed as LED.The cascade of each intermodule expansion for convenience, each module is all joined by a data input port, and data-out port, and all adding 74HC245 at the data-in port of each module and carry out data buffering, signal drives weak problem when preventing the cascade expansion.

Claims

1. LED display is characterized in that:

2. LED display according to claim 1, it is characterized in that in described LED dot matrix driver module, being provided with the version of dynamic scan, the LED basic display unit of each 16*32 is made of LED dot matrix screen unit, line scanning unit and column scan unit, described line scanning unit is the decoding scheme of the 4-16 that is made of two 74HC138, and each road output is with the indirect driving LED of field effect transistor of serial connection; Described column scan by be by the string with SPI interface-and conversion chip 74HC595 constitute, each LED basic display unit is by four 74HC595 chip cascades, its output directly drives 32 and is listed as LED.

3. LED display according to claim 2, it is characterized in that described single-chip microcomputer adopts the STC89C58 device, described programmable logic device (CPLD) adopts the EPM7128S device, between described single-chip microcomputer and programmable logic device (CPLD), be set to the bus communication mode, single-chip microcomputer passes through RD, W R, the multiplexing P0 mouth of data address, high address P2 mouth is connected with programmable logic device (CPLD), and single-chip microcomputer can pass through outer read/write instruction access programmable logic device (CPLD); Behind the Hanzi internal code that programmable logic device (CPLD) reception single-chip microcomputer transmits, this horizontal and vertical parity check code storehouse of search is to be put horizontal and vertical parity check code accordingly in the dot-matrix font storer externally, the point horizontal and vertical parity check code serial that will search then outputs to string-and conversion chip 74HC595, and the chip selection signal of synchronous shift pulse signal CLK, row decoding signal and LED lattice module is provided for dot matrix display screen simultaneously.