This moving LED Display uses four 5×7 Dot-matrix bar along with Max-6952 driver IC and AT89C51 Microcontroller. Max-6952 is LED dot-matrix driver IC from MAXIM. Max-6952 can drive up-to 4 Digits (140 LEDs) included static RAM that stores each digit, as well as font data for 24user-definable characters and built-In ASCII 104-Character. This max6952 IC is SPI Compatible. This Max-6952 IC can drive four single Colour matrix display or two bicolour matrix Display.
In this project, I have interfaced four single colour LED Dot-matrix Display with AT89C51 microcontroller using Max-6952. This Driver IC is very useful because we cannot interface four Digits directly to port pins without consuming almost all the pins, which is quite impractical.
BLOCK DIAGRAM OF MOVING LED DISPLAY
DESCRIPTION OF BLOCKS
1. 8051 Microcontroller (AT89C51)
In this project I have used AT89C51 Microcontroller which is 40 pin µC. This µc has 4KB of ROM and 128 bytes of RAM and built in Timer/counter, UART modules etc. It has Total 32 I/O pins. It can run on any frequency between 4 to 44 MHz and I have used 12 MHz in this particular project.8051 micro-controller doesn’t have SPI module in it so I have used its i/o pin to interface with SPI compatible Max-6952 Display driver.
2. Max-6952 IC
This Max-6952 IC can drive four single Colour matrix display or two bicolour matrix Display. It has total 40 pins. It can operate on 2.7V to5.5V.It included static RAM that stores each digit, as well as font data for 24user-definable characters and built-In ASCII 104-Character.This Max-6952 IC is SPI Compatible. It contains 16-bit shift register into which Input data are clocked on the rising edge of CLK, when CS is low. This IC have built-in ASCII 104 characters so to display any characters we have to just provide ASCII code in Hex to this IC through DIN (Data-Input) pin.
O0 to O13: These pins are connected to LED display’s anode.
METHOD TO INTERFACE IC-6952 WITH 8051
HOW IT WORKS
The MAX6952 interfaced with AT89C51 through an SPI-compatible serial interface. The interface has three inputs, clock (CLK), chip-select (CS), and data in (DIN) and one output, data out (DOUT).Here in this project, I have used only three input pins.
We need to configure four registers which are explained earlier. First we need to configure the configuration registers to select normal mode and blink disabled by loading address and data accordingly .We need to send write bit followed by address of configuration register and then data to sets the function. Then we need to set scan limit to select number of digit we want to us. Here we have used four digits so we need to load 0x01 data into scan limit register which has address 0x03.after that we have to set intensity of digit segments so here we set it to maximum using intensity register by loading data 0x0f and 0xf0 for digit 0&2 and digit 1&3 respectively. All this data must be loaded in to registers by using steps as I mentioned earlier.
After setting all these registers as per our requirement we need to provide data to data or digit register that we want to display. The data in the digit registers does not control the digits directly. Instead, the data means ASCII code is used to address a character generator, which stores the data of a 128-character font.
Project Source Code
Project Source Code
Filed Under: Electronic Projects