The rapid development of science and technology of traditional TV, magazines, newspapers and other media development has stagnated.
Booming emerging outdoor media, provide convenient rapid access to information for people.
Let me introduce you to the system design scheme of LED dot matrix display screen.
Composed of LED dot matrix display screen LED dot matrix display screen of: is composed of multiple LED light-emitting diode packaging together, is a kind of new display device.
To illustrate the principle of LED dot matrix display, with the single chip processor as the core, designed and produced a display system contains two parts of hardware and software.
This circuit can be realized through key control any number of characters of shutter, a variety of display forms up and left, can be widely used in airports, shopping malls, hospitals, public places such as text advertising, information release, etc.
And has small volume, circuit structure is simple and easy to implement, etc.
Display controller hardware circuit part of the system hardware circuit is mainly composed of three parts: serial communication interface, the expansion of the external memory and LED dot matrix display driver and interface circuit.
General to say to display content is more, so must expand external data memory.
Low cost, low consumption, the static data memory read and write speed, we use two pieces of static RAM62256 data memory (
A total of 64 KB)
To display the content of the code all the deposit to 62256.
System software program software is the core part of the whole control system.
System of the main program began after the first is to the system environment initialization, including setting up a serial port and port, timer, interrupt.
The whole software design mainly divided into two parts: the display part and communication part.
Communication part: PC software using Visual Basic programming, VB provides powerful functions of communication MSCOMM control, the control of a serial port and serial port communication message format and protocol configuration, using the PC serial port to send data directly.
For the realization of the single chip machine the reliable communication with a PC, must make the pledge that we both have the same data format and baud rate.
The use of the software is simple.
Can use Microsoft Word first handle when using need to display content,
Note that the width of the page setup with the LED dot matrix display screen width should be the same)
, and then select edit menu selection command and replication, then run the V1 LED display download software.
Interface, select the 'clipboard' button, you need to download the contents of the can display in the preview box, after checking, select baud rate and connected to the serial port, click on the 'download' button, you can download the display.
Need to modify or to display new content repeat the above operation can be done.
Display section: use a dynamic scanning way, realize the on screen display Chinese characters, characters, images and data transmission control and display functions.
Program in data storage is divided into three areas: display buffer, according to the storage area and the receive buffer.
Microcontroller through the serial port interrupt receiving data from the PC, temporary storage after the receive buffer analysis, according to certain rules in the data store to save, and then according to the display mode sequence data extracted from the data in the memory to the display buffer.
Show with the method of line by line scan.
PC part of real-time communication is mainly using single-chip microcomputer serial port interrupt receiving data information, implementation of data information transmission with the computer.