LedCount Library

Projects Programming
1

Hello All,
I have one Nano Every board and two MAX7219s connected to two 7-seg displays,
one 4-digit (lc1) and one 3-digit (lc2). In my declarations I have..
LedControl lc1 = LedControl(12,11,10,1);
LedControl lc2 = LedControl(7,6,5,1);
lc1 works fine but I cannot get lc2 to work. Do I have to drive all 7 displays from lc1?
I have them mounted on a PCB with the sets of displays 220mm apart. the Nano Every is close to the first Max with three lines going across the board to the other MAX. I thought I could do this with only three lines between them. Do I have to run another 10 wires between them and use just lc1?
Sorry forgot to add, I have in setup.....

  lc1.setIntensity(0, 6);  // 0 -- 15
  lc1.shutdown(0,false);  // wake up MAX7219
  lc2.setIntensity(0, 6);  // 0 -- 15
  lc2.shutdown(0,false);  // wake up MAX7219

and in loop ...

    lc1.setChar(0, 3, '-', false);
    lc1.setChar(0, 2, '-', false);
    lc1.setChar(0, 1, '-', false);
    lc1.setChar(0, 0, '-', false);

and...

    lc2.setDigit(0, 2, 0, false);
    lc2.setDigit(0, 1, 0, false);
    lc2.setDigit(0, 0, 0, false);
3

@Delta_G
I think I found a reference...
https://wayoda.github.io/LedControl/pages/software

4

if lc1 is working but lc2 not it might be that you messed up the wiring for lc2.
We can't see your wiring nor your code.

5

Thanks for the replies.
So my definition for lc2 is ok and it SHOULD work on different pins from lc1.
Is that correct? I will check wiring.

6

don't mix to many things.
Start with the hello World example vom LC and add a second display object.
No TM1637
No I2C
No BMP
No Interrupt.

We still can't see your wiring.

7

OK tried this code and again lc1 display works but lc2's does not.

#include <Wire.h>
#include <LedControl.h>
LedControl lc1 = LedControl(12, 11, 10, 1); //din, clk, load, no of max7219s
LedControl lc2 = LedControl(7, 6, 5, 1); //din, clk, load, no of max7219s

void setup()
{
  lc1.shutdown(0, false);  // wake up MAX7219
  lc1.setIntensity(0, 6);  // 0 - 15
  lc2.shutdown(0, false);  // wake up MAX7219
  lc2.setIntensity(0, 6);  // 0 - 15
}

void loop()
{
    lc1.setDigit(0, 3, 1, false);
    lc1.setDigit(0, 2, 2, false);
    lc1.setDigit(0, 1, 3, false);
    lc1.setDigit(0, 0, 4, false);

    
    lc2.setDigit(0, 3, 1, false);
    lc2.setDigit(0, 2, 2, false);
    lc2.setDigit(0, 1, 3, false);
 }
8

All library examples have a lc.clearDisplay in setup.
Change Module 1 by Module 2 to exclude a hardware error.

And just in case it wasn't mentioned already:
we don't see you wiring, nor your modules, nor your power source.

9

its ok. it was a hardware problem. there was a metal standoff pillar which was shorting pin 5 of lc2 to earth. thanks for the help all.

10

good to hear.

Just in case you prefer to have an easier possibility to print digits like

lc1.print(a);

I suggest you have a look at my modified library:
https://werner.rothschopf.net/201904_arduino_ledcontrol_max7219.htm

there is even the possibility to use HW-SPI (and reuse MOSI/CLK lines for both displays).

11

Cheers noiasca.

12

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