thanks for your help! I didn't post my code since I used the demo code from the library.
//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(12,11,10,1);
/* we always wait a bit between updates of the display */
unsigned long delaytime=250;
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();
}
Since this didn't work, I modified it a bit, but nothing special, just like making a number out of the i's.
I checked the wiring together with my gf, so I'm not allowed to say there could be a mistake But look, here's my "proof" why wiring has to be "correct". For the moment, I don't care if segment a is wired to segment a (even if I wired it this way), since I want it to display 8s on every digit, including the point. So all segments have to light up in a way. If I send random numbers to the display, every segment lights up (just not the correct ones for the specific number), so I know cathodes and anodes are correct. And this leads me to the conclusion that the wiring is probably correct, but either way, for an 8, everything should light up.
I'll try the segment information idea.