strange behaviour with a single 7seg display

Question

I'd like to display a sentence character by character on a single seven-segment display. What happens is that if my sentence is longer than 48 characters the central segment doesn't light up.

It works properly if I take out a letter from my string.

I have an Elegoo Uno R3, and am working on Windows, on the last version (2.0.3) of the Arduino IDE.

Is there a way to solve this issue?

Here's my code:

# include "SevSeg.h"

SevSeg  sevseg;
char    *str = "Per colpa di qualcuno non si fa credito a nessuno";
int     len = 50;



void setup(){
    byte numDigits = 1;
    byte digitPins[] = {};
    byte segmentPins[] = {6, 5, 2, 3, 4, 7, 8, 9};
    bool resistorsOnSegments = true;

    byte hardwareConfig = COMMON_CATHODE; 
    sevseg.begin(hardwareConfig, numDigits, digitPins, segmentPins, resistorsOnSegments);
    sevseg.setBrightness(90);
}

void loop(){
  int i = 0;

  while (i < len)
  {
    sevseg.setChars(&(str[i]));
    delay(1000);
    sevseg.refreshDisplay();
    ++i;
  }
}

Thanx in advance,

Fab

Answer 1

It looks like setChars is expecting a string, not a single character.

So I would be doing something like:

  while (int i = 0; i < len; i++)
  {
    char buf [2];
    buf [0] = str[i];
    buf [1] = 0;  // null terminator
    sevseg.setChars(buf);
    sevseg.refreshDisplay();
    delay(1000);
  }

See: https://github.com/DeanIsMe/SevSeg/blob/master/SevSeg.cpp