Atmel AT90S2313 Computer-Controlled Scrolling LED Text

There are pcb, schematic and source orcad drawings in the image format of the computer control program atmel at90s2313 source software, shared with all the details of the marquee circuit.

About the marquee circuit

350 leds are used in the marquee circuit, the microcontroller atmel at90s2313 leds are driven with 7 pcs of 74hc595. It receives the text information from the computer via the serial port, the pc program works with windows xp, and the source of the program is Borland C++ files.

The display has seven rows of 50 LEDs each. The display controller consists of seven transistors and seven 8-bit shift registers, all controlled by the MCU (AT90S2313). Each transistor drives a line by choosing whether it is enabled or not. The shift registers are chained together, so the serial inputs are converted to a 56-bit parallel output, 50 of which are used to drive the columns. The last six bits remain unused.

The MCU updates the display one line at a time. When displaying a line, it feeds the content of the next line into the shift registers. After that it disables the current line, enables the next one, and commands the shift registers to display their data on outputs. This cycle is performed hundreds of times per second creating the entire image on the screen.

The device has a 2 kilobyte (24c16) EEPROM memory used to store static text and font. The contents of the memory are read and written by the MCU, which either follows the commands received through the computer interface or reads and repeatedly displays the static text operating independently on the screen.

The computer serial interface uses the regular UART (9600bps, 8 bits, 1 stop bit, no parity) to communicate with the computer software. The device continues to send the status of the receive buffer to the computer: each byte sent tells how many bytes of free space are in the buffer. If the device receives a byte from the computer, it checks whether it is a command byte. If not, the byte is considered a text character and the corresponding character image in the EEPROM is displayed on the screen. If a command is recognized, the MCU will act as intended. Extra bytes are ignored in case of serial buffer overflow.

Scrolling LED Features

50 x 7 LED
Computer link RS232 (serial port)
The optional static text or dynamic text (from the computer)
Automatic text source selection
The longest static text length of 768 characters
Programmable text, 256 different characters
Character width of 0-5 pixels (+ optional blank column)

About the program that sends text over the computer

Combining electronic circuits and computer is a very good event, unfortunately I do not have knowledge about programming, but I think that the marquee program will be very useful for people who deal with c++ and have electronic knowledge, and can be developed for different applications or pic series microcontrollers. In addition, it has a very good and useful face, and with the “Play from web” option, text can be sent from a site on the web.

Example to use test submission software

Source: koti.mbnet.fi/zyc/LedDisp Computer Scrolling circuit schematic pcb etc. alternative link: