MAX 7219 and MAX 7221 quite commonly used display driver IC for LEDs. Actually the same IC was in the 8×8 LED Matrix display. Right now, we know about 7 segment LED display as electronic component and multiplexing (increasing the number of digital pins in Arduino). Here is how to create Arduino MAX 7219 CNG basic circuit to control LED, 7 Segment displays in own custom ways rather than using modules. Arduino has official support for this chip :
This guide is very important for the beginners as you are going to learn to use MAX 7219 CNG as component and enjoying the freedom to be creative. Instead of limited size of TM1637 clock, or miniature traffic light with TM1637, you can create a custom size clock or something like that. Additionally you are learning where from CLK, DIO, GND, +5V pins of modules actually originated. TM1637 vs MAX7219 is a complex topic but in easy language – TM1637 through hole component not so easily available and usage is limited.
Arduino MAX 7219 CNG Basic Circuit
MAX 7219 CNG and MAX 7221 both are costly chips, that is the basic problem. One MAX 72xx can control maximum of 64 LEDs. In most basic form, you need to create a kind of 4 digit LED 7 Segment display from 7 Segment display component (or buy a ready to use such which has no chip, the hardware interface is two rows of six through-hole pins) and this will be the circuit diagram :
The code will be like this to test :
LedControl lc = LedControl(4,5,6,4);
int count = 1000;
String t = String(count++);
However, for real good, stable circuit, you need to add two capacitors – one 10 uF electrolytic capacitor and a 100 nF ceramic capacitor in the circuit and create a 8×8 matrix with component LEDs. Circuit, in that case will be like this :
It is very important to study MAX 7219 CNG from various web resources for advanced works.