Whar is SCL and SCA in a LCD

In the photo de LCD is connect to the arduino with SCL in A5 and SCA in A4.
I don't understand what and where are the SCL and the SCA in a LCD
Can someone help me?

Some LCDs are sold with serial to parallel adapters called "backpacks". I2C backpacks will have VCC, GND, SDA, SCL pins.
If your LCD doesn't have an extra small pcb soldered to its pins on the back then you have to connect in a different way, take a look here:

Make sure you connect everything to the correct pins, the pins on the LCD should be numbered (on some they are also labeled).
Check the datasheet for your display and connect everything by pin names rather than the schematic.

So how can i do this diagram without using the SCL and SCA?

Ok, let's start from the beginning. What LCD do you have? A link to the product page and datasheet will be helpful.

You can see my LCD here:
http://www.ebay.co.uk/itm/LCD1602-3-3V-Blue-Backlight-16-2-Lines-White-Character-LCD-module-1602A-QAPASS-/400534753173?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item5d41bb4f95

I can't find the producer

You can’t make the diagram you posted work with that display as it doesn’t have I2C support.
You can use the guide I posted. Note that your display is designed for 3.3v, Arduino Due is a 3.3v board, all the other Arduino’s are 5V boards and will probably not work right with (or even damage) your display.

That's true i don't understand a lot about this but i can't turn on the backlight.
Can i do the do that progect with my LCD right but i have to change the connection from de LCD to the arduino right?

I see you having a world of difficulty with that particular LCD panel - it is a trifle odd by comparison with what we are familiar.

You are going to need something different to use it. I suggest getting a whole new display with the "backpack" that supports the I2C as in your diagram, such as this one. Then you need to connect only the display and run through various practice sketches to become familiar with it before ever approaching the complexity of what you illustrate.

There are other options to be sure, but they are going to involve more complexity again.

I see you having a world of difficulty with that particular LCD panel - it is a trifle odd by comparison with what we are familiar.

He's is going to have trouble with that particular LCD panel only because his application calls for a serial display and his is parallel.

There is nothing odd about it in the least. Parallel LCDs like his are probably a lot more common than all of the various serial versions put together.

Don

floresta:
There is nothing odd about it in the least. Parallel LCDs like his are probably a lot more common than all of the various serial versions put together.

I think not. How many LCDs have you seen that are intended to run at 3.3V?

Does it require a negative bias for the contrast - I rather suspect it does? The information given in the eBay reference is thoroughly garbled - it refers to the "LED Drive Voltage (Vdd-Vo)" as "+3.0 ~ +3.5V" which is singularly confusing.


Further research indicates that the difference between the 5V version and the 3.3V version would appear to be the presence in the 3V version of the charge pump IC U3 with its pump capacitors C1 and C2. I presume that could actually be simply disabled and the display turned into the 5V version by clearing jumper J1 and bridging J3 instead.

I imagine this functions by adding to the positive supply voltage for both the HD44780 and the LCD. Since the contrast point is close to the negative (5V, "Vss") rail, having the contrast potentiometer between this rail and either 3V or 5V positive will work.

There is also the strong implication that since the display is internally generating a 5V supply, it really will not matter if the interface is fed with 5V levels rather than 3.3V.

Did you try google search "LCD1602 arduino" ?

Paul__B:

floresta:
There is nothing odd about it in the least. Parallel LCDs like his are probably a lot more common than all of the various serial versions put together.

I think not. How many LCDs have you seen that are intended to run at 3.3V?

Everything recent is 3.3V! Look on eBay...

Most common HD44780 displays are 5V. Usually TFT LCDs are the ones which are 3.3v.

ARDUINO UNO R3 has the SCL and SCA pins unlabeled between the last digital I/O and RESET button.

http://pighixxx.com/unov3pdf.pdf

R3 also has a 3.3 v pin on the other side beside the 5v pin.