20X4 (Not I2C) no output

Using Arduino Displays
1

Hi everyone my first post so please bear with me.

I have several 20x4 and 16x2 display units which all have the same problem.

Sketches compile and seem to upload OK ( according to the flashing leds but I can not get any output ( letters, numbers or characters _) I have tried uno / nano / mega and they all give the same result I have tried so many example sketches I have lost count.

This is the latest one tried :-

/*
This sketch will display a series of numbers 0-44 on a LCD screen 20x4 filling each line with consecutive numbers until it reaches
the end and then it starts again.

Code used for learning purposes developed by: www.HackerspaceLA.org | @hackerspacela
Code modified from Adafruit at: https://www.arduino.cc/en/Tutorial/LiquidCrystalAutoscroll
This example code is in the public domain: http://www.arduino.cc/en/Tutorial/LiquidCrystalAutoscroll
*/
// include the library code:
#include <Wire.h>
#include <LiquidCrystal_I2C.h>

//#define pins:

#define I2C_ADDR 0x27 // LCD address (make sure you run the I2C scanner to verify our LCD address)
#define Rs_pin 0 // Assign pins between I2C and LCD
#define Rw_pin 1
#define En_pin 2
#define BACKLIGHT_PIN 3
#define D4_pin 4
#define D5_pin 5
#define D6_pin 6
#define D7_pin 7

LiquidCrystal_I2C lcd(I2C_ADDR,En_pin,Rw_pin,Rs_pin,D4_pin,D5_pin,D6_pin,D7_pin);

// initialize the library with the numbers of the interface pins

void setup() {
// set up backlight and turn on module:
lcd.setBacklightPin(BACKLIGHT_PIN,POSITIVE);
lcd.setBacklight(HIGH);
// set up the LCD's number of columns and rows:
lcd.begin(20, 4); //My LCD is 20x4

}

void loop() {
// set the cursor to (0, 0) on line #1
lcd.setCursor (0, 0);
//lcd.autoscroll();
// print from 0 to 14:
for (int thisChar = 0; thisChar < 15; thisChar++) {
lcd.print(thisChar);
lcd.leftToRight();
delay(500);
}

// set the cursor to (0, 1) on line #2
lcd.setCursor (0, 1);
// set the display to automatically scroll:
//lcd.autoscroll();
// print from 0 to 14:
for (int thisChar = 15; thisChar < 25; thisChar++) {
lcd.print(thisChar);
delay(500);
}

// set the cursor to (0, 1) on line #3
lcd.setCursor (0, 2);
// set the display to automatically scroll:
//lcd.autoscroll();
// print from 0 to 14:
for (int thisChar = 25; thisChar < 35; thisChar++) {
lcd.print(thisChar);
delay(500);
}

// set the cursor to (0, 1) on line #4
lcd.setCursor (0, 3);
// set the display to automatically scroll:
//lcd.autoscroll();
// print from 0 to 14:
for (int thisChar = 35; thisChar < 45; thisChar++) {
lcd.print(thisChar);
delay(500);
}

// turn off automatic scrolling
lcd.noAutoscroll();

// clear screen for the next loop:
lcd.clear();
}

I would appreciate if anyone could point me in the correct direction as in this case google is NOT my friend/

thanks in advance

Keith

2

OK, well your first task is to go and read the instructions, then go back and modify your post (use the "More --> Modify" option to the bottom right of the post) to mark up the code as such so we can examine it conveniently and accurately.

If you do not do this, the code you post could well be garbled and is certainly anything but easy to read.

Note: Also mark up any data in the same way. This includes error output that you get from the IDE.

And - before you post code, use "Auto Format" in the Tools menu to properly present the code.

Try and avoid unnecessary white space (blank lines). You should only use these to separate functional blocks of code.

Until you reply and demonstrate that you understand these points that have been made so far, there may be a lack of enthusiasm for getting into your problem.

Kaybee327:
Hi everyone my first post so please bear with me.

That is strange! So where did the other eight under your name come from?

OK, we need you to demonstrate how you wired the display and what (in detail) you actually see on the display. But surely that would be obvious to expect?

3

Are you sure of the LCD I2C address and I2C backpack to LCD pin mapping.

The hd44780 LCD library will autodetect the address and pin mapping. The library is available for installation through the IDE library manager.

4

I'm confused. Title says "Not I2C" but the example is for an LCD using a specific I2C backpack.
What do you have and how do you have it hooked up?

--- bill

5

Gentlemen, OOPS :grin:, please accept my apologies.

  1. I am not surprised it did not work.
  2. Well spotted.
  3. Just goes to show the older you get the more stupid one can become.
  4. Please ignore all and I will try with the correct version and come back.

Thank you all

Keith

6

All OK, but now we want to know what actually was the problem?