4BitLCD - 2nd line not working

Forum 2005-2010 (read only) Hardware Interfacing
1

Hi,

I am using the arduino + 4BitLCD library on a Powertip 1602-F LCD display.

The example supplied runs fine so no issues with wiring etc. However :

  • when I try to use lcd.cursorTo(line, pos) : the display just goes blank forever (until I reset the arduino)
  • when I try to init as a two-line display , the display just goes blank, even with the example code just writing to line 1 (i.e. it doesn't init properly ?)

Can anybody help ?

Kind regards,

Frank

2

Frank, if you are running Arduino version 0012, try it with the LCD library provided with the distribution.

3

Hi,
tried that now (standard library on Arduino 0012, using 4 bit wiring) but it doesn't init at all (stays blank). Unlike the 4bit library, this time I connected RW to a real pin (13) of the arduino as it seems to require that ?

No luck, I cannot get it to work.

I guess next time I'd better buy a serial LCD ?

Kind regards,

Frank

4

Hi Frank, not sure this will matter, but If your Arduino has an LED on pin 13 try using a different pin for the RW line.

5

Hi,
have you noticed, that you connect (in 4bitLCD) DB4-DB7 on LCD, and in the example it says you should connect DB0-3?
Well, this is a problem, because some manufacturers actualy name their pinout like so:
DB0
DB1
DB2
DB3
DB4 / DB0
DB5 / DB1
DB6 / DB2
DB7 / DB3

So no matter what library you use, you should connect the same (last 4) DB's :wink:

It worked fine for me. As for the picture: I user 220 Ohm resistors for DB's, and some pull down resistors, because I found this in a circuit of a working board. Don't know if any of this is reeeealy necessary, but I have destroyed two LCD's, don't know why, until I used this wireing.

For pin 3 it is for contrast and I used this resistors as I allready have an additional resistor soldered up my lcd (it is 100 Ohm between pins 3 and 5), so I don't know how will contrast look on your LCD, but you can try my way :slight_smile:

p.s.: don't think pin 13 should be the problem, as R/W is always set to low, because we only Write on the lcd...

Regards,
Peter

6

Forgot to add... I am using the library from the sample in arduino, and the second line is working, see the picture (arduino, fancy dressed up ::slight_smile: )

The code goes like so:
lcd.print("first line");
lcd.setCursor(0,1); // "zero" caracter on "first" line, as the actual first line has a 0 index
lcd.print("second line");

7

OK guys,

any of the above didn't work but I changed the LiquidCrystal code (4 bit initialiser) to :

  command(0x38); 
  command(0x28); 
  command(0x28); 
  command(0x0F); 
  command(0x01); 
  command(0x06);

instead of the original

  command(0x28);  // function set: 4 bits, 1 line, 5x8 dots
  command(0x0C);  // display control: turn display on, cursor off, no blinking
  command(0x06);  // entry mode set: increment automatically, display shift, right shift

Referring to page 49 of 65 of the Powertip datasheet and now it works mostly. Apparently it needs a different startup sequence ? (Though the 4BIT LCD library was working on 1 line only).

I will keep on reading the datasheet and posting to this topic for reference (other Powertip users ?).

Frank

8

Or change

command(0x0F);

in the above lineup to

command(0x0C);

for cursorless mode

Frank