OK.  That shield does not have any kind of serial interface and it uses the standard LiquidCrystal library.  You will be able to use your 'LCD without shield' with the same code as long as you wire it up with the six lines (RS,E,D4,D5,D6, and D7) going to the same Arduino pins as they do on the shield.  Take a look at the first customer review on your second link.  The alternative would be to use the same wiring as in the Tutorial, or use any other combination of I/O pins that you care to,  and change the LiquidCrystal lcd(...) statement to match.

Don't forget to deal with the backlight wiring.

Don

My question is:  Is the code equal with or without shield version?  I am talking about simple functinos like "hello word", of course my shield has buttons, the one without will not do that... but i talking about simple text funcion, does it work the same way??
I read somewhere that i would need to change some i2c address ?!

The only way that you can possibly get an accurate answer is if you provide us information that will positively and unambiguously identify exactly which shield and which 'LCD without shield' you have.

I can say that if your shield uses I2C and your 'LCD without shield' uses the 14-pin parallel interface then the answer is no.

Don

did you hook up the lcd r/w pin to ground?

I wish I had thought of that.  Oh, I did, and I got it posted more than a minute before you!
(just pulling your leg, Bill)

You declared them yourself with this line:

Code:

int A0,A1,A2,A3,A4,A5;

That is part of the 'extra code' that he was supposed to remove.

Don

You shouldn't need all the extra code that you added to deal with the 'pinMode' since that is handled by the LiquidCrystal library.  All you should have needed was the change you already made to the 'LiquidCrystal lcd(); contents.  

I believe that LiquidCrystal lcd(A0, A1, A2, A3, A4, A5); should have worked, but you could also try LiquidCrystal lcd(14, 15, 16, 17, 18, 19);.

I hope you didn't forget to ground LCD pin 5 when you reworked your circuit.

Don

Did you connect LCD pin 5 to GND?

Don

In general a microcontroller's logic 1 (high) level is nominally the same as it's supply voltage.  For the 'due' this would be 3.3v.

Don

It would help to know if the datasheet that MAS3 found is actually the correct one for your LCD module.

Don

But now the display only writes to the first two lines, no mater what I do.

In serLCD.cpp we find:
// Contstructor
// defaults to 16x2 display
And a few lines below we find all of the code that modifies this default has been commented out.

Don

backlight is reported 16mA.

This means that the rated current is 16 mA.

but you might want to consider using a resistor to limit the backlight current.

No. You must use a resistor to limit the backlight current to no more than 16mA.

Don

Back to your first post "What am I missing?"

I want to make sure that you have figured out that using the 8-bit interface does not provide access to any more (or any fewer) features than does the 4-bit interface.  The 4-bit mode does free up four I/O ports at the expense of some fancier programming (which you don't have to do since it is provided by the library) and an insignificantly slower access time.

Don

(I skipped position 0 in order to be able to use sprintf() without null-terminating the string.)

You can access position 0 by using address 8.

Don

I think you had better start by figuring out how the 'blinky' sketch works.  Then use that knowledge to get the same type of action with a single external LED.  Only then will you be ready to even consider dealing with a seven segment display, much less a 4-digit multiplexed version.

Don

But how to i stop it from being connected to GND?

That would depend on how you connected it to GND in the first place.

If you are using a wire in a breadboard hole you pull the wire out.

If you are using a switch you open the switch.

If you are using a transistor then you bias the transistor (drive it with the proper base signal) until it is not conducting.

If you are using a microprocessor I/O port you make the port 'high' or '1'.

Don

The screen is blinking (not the back-light) ...

To fix this part you will have to avoid clearing the screen each time around the loop.  Remember that you do not have to continually erase and then rewrite the parts of your message that do not change.

Don

The characters from the previous print are still on the screen... You can use clear() to clear the whole screen or what I do is just print a "         " before you print the next value, just to make sure nothing is left in that part of the screen.

Printing the spaces generally results in a more pleasing display than clearing the screen.

Don