16x2 LCD Serial communication Showing strange character

Projects Programming
1

when i send any character my lcd prints it but one strange character (4 horizontal lines) appears after that. what is the problem in code pls correct me.

#include <LiquidCrystal.h>


const int rs = 12, en = 11, d4 = 5, d5 = 4, d6 = 3, d7 = 2;
LiquidCrystal lcd(rs, en, d4, d5, d6, d7);
void setup() {
 
  lcd.begin(16, 2);
 
  lcd.print("hello, world!");
  Serial.begin(9600);
  lcd.setCursor(0, 1);
}

void loop() {
  
  if(Serial.available()>0)
  {
   
   lcd.write(Serial.read());
  }
}
2

a)
please edit your post and post your code in code tags

b)
I assume you close your serial input with a linefeed and/or Carriage return.
These might lead to the lines.

either don't send linefeed/Carriage return or just don't print non printable characters

if(Serial.available()>0)
{
  char c = Serial.read();
  if (c > 0x20) lcd.print(c);
}

untested.

1 Like
3

thanks friend. it worked.
but can u explain me this "if (c > 0x20)". why did it solved my problem.

4

google for "ASCII Table".

You will see that the lowest printable character is the blank. it is dec 32 or 0x20 in hex

and now I see, you should use

c >= 0x20)

to include also the blanks. As alternative you could write

c >= ' ')

that will do the same.

5

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