Hello all
I am trying to display some digits on a 3 digit 7 segment display but for some reason i have some problems with it
below you will find the fritz how everything is connected
The 7 segment is Common Cathode
I use the example sketch LCD Demo 7 segment
//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();
}
my problems are 2
1 if i read the schematic of MAX7219 correctly i should connect the arduino gnd with PIN 4 & 9 if i do that the 7 segment is flashing and doesn't show anything.
2 If i leave the gnd unconnected then the 3 digit 7segment shows the half of the things that should be shown and then it switches off.
Any ideas why ?