Arduino seems to run both old and current program

Other Hardware Displays
1

Whenever I attempt to run this code:

#include <Wire.h>
#include <Adafruit_RGBLCDShield.h>
#include <utility/Adafruit_MCP23017.h>
Adafruit_RGBLCDShield lcd = Adafruit_RGBLCDShield();

unsigned long timStart =  0;
long timEnd = 0;
int pause = 500;
boolean flash = true;

byte flasherChar[] = {
  B11111,
  B11111,
  B11111,
  B11111,
  B11111,
  B11111,
  B11111,
  B11111
};

byte upChar[] = {
  B00100,
  B01110,
  B11111,
  B00100,
  B00100,
  B00100,
  B00100,
  B00100
};

byte downChar[] = {
  B00100,
  B00100,
  B00100,
  B00100,
  B11111,
  B01110,
  B00100,
  B00000
};

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  lcd.begin(2, 16);
  lcd.createChar(0, flasherChar);
  lcd.createChar(1, upChar);
  lcd.createChar(2, downChar);
  lcd.setCursor(0, 0);

}

void loop() {
  // put your main code here, to run repeatedly:
  timStart = millis();

  int i;
  int charNo;
  String charList[] = {"u", "d"};

  Serial.println(i);
  if (lcd.readButtons() == 8 ) {
    Serial.println("u");
    charNo = 1;
  } else if (lcd.readButtons() == 4 ) {
    charNo = 2;
  }





  if (timStart - timEnd >= pause) {
    if (charNo > -1) {
      lcd.write(charNo);
      charNo = -1;
    }
    

    timEnd = timStart;
  }


}

a left pointing arrow is continuously written on the lcd screen, one after the other, despite never having a left pointing arrow custom character defined in this program (I wouldn't expect it to do this with one of the defined characters either).

I believe this is because it somehow remembers the character from a previous sketch, though I cannot find that sketch anywhere. I realise there are flaws in the code but it does still run, I am just confused as to how a leftt pointing arrow ( a different style to the defined ones too) is being written to the screen.

Thanks this is my first forum post so apologies for any incorrect formatting or missing info.

2

OK, let's have a photo.

3

Paul__B:
OK, let's have a photo.

I have now attached an image of what happens when I upload the program, wait a moment, press the up arrow once, wait a moment, then press the down arrow once.

Thank you and again sorry if this is not enough information.

20200409_104658 (2).jpg
20200409_104658 (2).jpg2890×2044 844 KB

4

Here's the image:
20200409_104658 (2).jpg

harrydotknee:
a left pointing arrow is continuously written on the lcd screen, one after the other, despite never having a left pointing arrow custom character defined in this program (I wouldn't expect it to do this with one of the defined characters either).

Wouldn't you? :roll_eyes:


↑

That appears to be the "DEL" character, 0x7F, or the value -1 masked to 7 bits.

5

I see! Thank you so much, I was not aware of those characters, and the arrow looked the exact same as a character I had made before.