New version of MAX7219 based 4-digit serial seven segment LED display

This (SPI7SEGDISP4.40-1R) is a revised version of the previous SPI seven segment LED display (4 digit) board that displayed numerals and decimal points. The new version has a better quality seven segment LED display (LTC-4727JS) with three extra LED segments, as shown below. The additional colon segments are useful in projects where you need to display time (HH:MM or MM:SS).
LED display
The common cathode terminals (Digit 1, Digit 2, Digit 3, and Digit 4) of the four seven segment digits are connected to D3, D2, D1, and D0 pins of MAX7219 driver chip. The common cathode pin 4 of LTC-4727 goes to D4 pin of MAX7219. So, in order to turn on L1, L2, and L3 segments, D4 digit select pin of MAX7219 should be active. Here’s an example that shows how to interface this module with an Arduino board usinf the LedControl library.

#include "LedControl.h"
// Arduino Pin 7 to DIN, 6 to Clk, 5 to LOAD, no.of devices is 1
LedControl lc=LedControl(7,6,5,1);
void setup()
{
 // Initialize the MAX7219 device
  lc.shutdown(0,false);   // Enable display
  lc.setIntensity(0,10);  // Set brightness level (0 is min, 15 is max)
  lc.clearDisplay(0);     // Clear display register
}
void loop()
{
  lc.setDigit(0,0,4,true); // Display 4 to Digit 4, and turn DP on
  lc.setDigit(0,1,3,true); // Display 3 to Digit 3, " "
  lc.setDigit(0,2,2,true); // Display 2 to Digit 2, " "
  lc.setDigit(0,3,1,true); // Display 1 to Digit 1, " "
  lc.setDigit(0,4,7,true); // Turns L1, L2, and L3 on
  delay(1000);
}

Note that the DIN, CLK, and LOAD pins of the display are connected to Arduino pins 7, 6, and 5, respectively. For more details on MAX7219 device, see the original article.

For more detail: New version of MAX7219 based 4-digit serial seven segment LED display


About The Author

Ibrar Ayyub

I am an experienced technical writer holding a Master's degree in computer science from BZU Multan, Pakistan University. With a background spanning various industries, particularly in home automation and engineering, I have honed my skills in crafting clear and concise content. Proficient in leveraging infographics and diagrams, I strive to simplify complex concepts for readers. My strength lies in thorough research and presenting information in a structured and logical format.

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