Max7221 Led controller 7 segment display wireing

1

Good day,

I have the following problem… :

MAX7221 at 7 segment display . have the pins DIG0-DIG7 on com of the individual displays (common cathode) [DIG0 1st 7seg DIG1 2nd 7seg etc.] and SEG-A to SEG-DP on the segments a-dp on the displays.

Unfortunately, the display lights up completely… but you can see that it is being controlled because some elements are displayed alternately brighter.

Resistor and capacitor are also available… someone spontaneously a tip? or can someone tell me whether the wiring is correct for the time being… I think so, I just have no plan where the error could be.

2

But… you posted neither wiring nor any code.

3

if i short circuit com with seg-a i get at least a few hyroklupes…

Questions about the tangle of cables are welcome.

4
5

code is simply the ledcoontrol example :slight_smile:

#include <Arduino.h>
#include <SPI.h>
//We always have to include the library
#include “LedControl.h”

/*
Now we need a LedControl to work with.
***** These pin numbers will probably not work with your hardware *****
pin 12 is connected to the DataIn
pin 11 is connected to the CLK
pin 10 is connected to LOAD
We have only a single MAX72XX.
*/
LedControl lc=LedControl(23,18,5,5);

/* we always wait a bit between updates of the display */
unsigned long delaytime=100;

void setup() {
/*
The MAX72XX is in power-saving mode on startup,
we have to do a wakeup call
/
lc.shutdown(0,false);
/ Set the brightness to a medium values /
lc.setIntensity(0,8);
/ and clear the display */
lc.clearDisplay(0);
}

/*
This method will display the characters for the
word “Arduino” one after the other on digit 0.
*/
void writeArduinoOn7Segment() {
lc.setChar(0,0,‘a’,false);
delay(delaytime);
lc.setRow(0,0,0x05);
delay(delaytime);
lc.setChar(0,0,‘d’,false);
delay(delaytime);
lc.setRow(0,0,0x1c);
delay(delaytime);
lc.setRow(0,0,B00010000);
delay(delaytime);
lc.setRow(0,0,0x15);
delay(delaytime);
lc.setRow(0,0,0x1D);
delay(delaytime);
lc.clearDisplay(0);
delay(delaytime);
}

/*
This method will scroll all the hexa-decimal
numbers and letters on the display. You will need at least
four 7-Segment digits. otherwise it won’t really look that good.
*/
void scrollDigits() {
for(int i=0;i<13;i++) {
lc.setDigit(0,3,i,false);
lc.setDigit(0,2,i+1,false);
lc.setDigit(0,1,i+2,false);
lc.setDigit(0,0,i+3,false);
delay(delaytime);
}
lc.clearDisplay(0);
delay(delaytime);
}

void loop() {
writeArduinoOn7Segment();
scrollDigits();
}

6

HELP :smiley: :smiley: HELP :smiley: :smiley: * jump jump i never thought that that would be such a act with these 7-seg`s

7

Thanks I don’t need any more help, I just found out that I got the wrong display although I was sure it was a common cathode