The difference between sending commands and sending text to the LCD is pulling RS LOW. I suppose you could carefully check that wire/solder connection
Thanks for reply Jr,my RS pin (the 4th in my case) is receiving a 0 from pin 12.
Perhaps it would be in your best interest to read the first 10 lines of your program, then take a close look at your LCD. Notice the driver that your LCD uses and the driver that the LCD library expects the LCD to use.
Interpolating a pair of information I have to say that the lcd is an Hitachi 44780 compatible. In datasheet driver is indicated as an S6A0069/65
The 4-bit Arduino LCD library
What is it? Why?
This is an unofficial Arduino library which allows your Arduino to talk to a HD44780-compatible LCD using only 6 Arduino pins. It is neillzero's conversion of the code from Heather's original Arduino LCD tutorial which required 11 Arduino pins.
Download it! (includes an example sketch).
This library should work with all HD44780-compatible devices. It has been tested successfully with:
- Xiamen GDM1602K (from Sparkfun)
- Display Elektronik DEM 16101H (16x1) and DEM 16217SYH (16x2) (from Maplin).
- Display 20x4 (KS0066U-00PCC et KS0065BPCC controllers, HD44780 code compatible) usable with Jonathan's modified library to get all 4 lines working: (From LEXTRONIC France) (this version also adds some optimizations and WriteCGRAM to use user-defined characters). Read more on 20x4 modifications.
- Display 16x2 (KS0066 controller, black & white, no back-light, HD44780 code compatible). First line is working, but both lines are greatly dimmed when displayed at the same time (I think it's a problem in my circuit, not in the library)
- Hantronix HDM16216L-B display, 16 characters X 2 lines.
- Tianma TM404A, 40 characters x 4 lines, first 2 lines are working, for third and fourth line a modification is necessary, see LCD4BitLibrary-tm404a
- Everbouquet MC0802A-SGR, little 8x2 (from Farnell)
- DMC16249 2x16 display from Optrex
- DE-LM001, 8 characters x 2 lines (from Sure Electronics)
- Emerging Display Technologies Corporation display # 24210
- Sharp LM40A21, 40x2, using HD44780A00. Mostly worked, adding a delay(2) after the CMD_HOME in cursorTo() fixed periodically garbled display problem. The HD44780 datasheet (pdf) I looked at specifies a 1.52ms delay for the Return home command at nominal f_osc of 270kHz, but it appears that this value could be as high at 2.16ms at low end of f_osc range, 190Khz.
- POWERTIP PC-4002B A, 40x2
- Tinsharp TC1602A-09T, 16x2
- Displaytech 162B, 16x2 (from RS)
- ECM1602A (16x2, S6A0069 based)
- Batron BTHQ21608VSS (16x2, based on the Samsung KS0070BP-00CC)
- DEM16217 2x16 from Segor (Datasheet)
- NHD-0216K1Z-NSB-FBW-L (Newhaven Display 16x2)
- Dalian YM1602C (edited code to move Enable pin from 2 to 11)
- Hitachi LM071L
- Winstar WP2002A-Y-JCS 20x2
- Tinsharp Electronics TC1602D-02(R) 16x2 (added 2nd Apr 2009)
- Fordata Electronic FDCC1602G-NLYFTW-R
- Samsung 16T202DA1 (16x2 VFD Display)
- Samsung 20T202DA1E (20x2 VFD) Unused pins can be left floating
- add your tested device here
taken from http://www.arduino.cc/playground/Code/LCD4BitLibrary
and from seeedstudio
Hook everything up EXACTLY like in this picture from the Arduino page:
Now load the "Scroll" Example from Arduinos LiquidCrystal Library.
Change these two lines
now upload it to your Arduino or Seeduino and watch your display fire up!
You may have to adjust the potentiometer a little if you can't see anything.
As an alternative to the potentiometer you can connect the Vo pin of the LCD with any available PWM-output (I use pin 9) and add the following code in the setup() section:
replace CONTRAST with the value of your choice. Values around 10-20 give a nice bright output.
(thanks for above tutor from DedeHai)
which suggests to use a example based on Hitachi chip.
With the example code present in the 4 bit LCD library (another library, thanks Paul then) I'm able to fill my 16 digits with full black, not yet characters.Just have to mess with code.
Will post sketch and photos if could obtain improvements.