Interfacing LCD failes [Beginners question]

I try to connect a TRULY 20x4 LCD to a Arduino Mini 03. Therefore I followed the tutorials and used the LCD4Bit libraries. But I still get no result.

Hardware setup:

LCD Pin 01 (VSS) <-> Ground
LCD Pin 02 (VDD) <-> +5 from USB Mini
LCD Pin 03 (VO) <-> would be for the contrast, but not used
LCD Pin 04 (RS) <-> Mini D12
LCD Pin 05 (R/W) <-> Ground (as described in the forum to have R/W to ground, because only writing and no reading is used)
LCD Pin 06 (E) <-> Mini D02
LCD Pin 07 (DB0) <-> N/A
LCD Pin 08 (DB1) <-> N/A
LCD Pin 09 (DB2) <-> N/A
LCD Pin 10 (DB3) <-> N/A
LCD Pin 11 (DB4) <-> Mini D07
LCD Pin 12 (DB5) <-> Mini D08
LCD Pin 13 (DB6) <-> Mini D09
LCD Pin 14 (DB7) <-> Mini D10
LCD Pin 15 (Back light anode) <-> R 0,2 Ohm <-> +5V
LCD Pin 16 (Back light cathode) <-> Ground

LED <-> Mini D13

Software:

I used the LCD4Bit Library (neillzero) and code (LCD4linesExample) from the Playground “as is”, nothing changed.

Result:

LED is blinking, Back light is on but nothing is shown :frowning:

Does anybody has a hint for me?

KR
Greg

I try to connect a TRULY 20x4 LCD to a Arduino Mini 03. Therefore I followed the tutorials and used the LCD4Bit libraries. But I still get no result.

Hardware setup:

LCD Pin 03 (VO) <-> would be for the contrast, but not used

You need to connect a pot to provide a voltage on the contrast pin, otherwise the display is not visible.

see the tutorial for an example: http://www.arduino.cc/en/Tutorial/LCDLibrary

I connected LCD Pin 03 direct to GROUND --> and it works fine :)

Thanks!

Good to hear its working!

It may look even better with a little bit of voltage on the contrast pin. If the 'unlit' pixels are clearly visible, connecting a pot would give you a setting for best contrast between the on and off pixels. Next time you are throwing away an old CD ROM player or something else that uses small trim pots, you may want to dig out the soldering iron and 'repurpose' one.

Works good, played around during the last night.

Next Steps: - LCD3wires (from here http://www.arduino.cc/playground/Code/LCD3wires - use the LCD for debugging purposes

Thanks for the help!

Greg :)