cant get sparkfun serLCD v2.5 to work on arduino


i have looked at the schematic and datasheet but it looks nothing like the LCD

i know its a sparkfun serLCD

anyone got one and want to share some light please? i will love you long time ;D :wink:


Sparkfun sells several serial LCDs. Which one do you have?

I don't know whether I want you to

i will love you long time

its this one


anyone :-[

Does your serial LCD look like the picture on the Sparkfun site, like the one on the datasheet, or like neither one?

its the same as the pic but not the data sheet

i have found the pin out anyway

here for people struggling in future

BUT even with it all hooked up and using example code in the libary all my LCD will do is do this

doing my head in - been trying to get it to work since 3 this afternoon :-/

This probably isn't the problem, but try turning the Contrast potentiometer. Many people seem to have that problem. :stuck_out_tongue:

tried it :frowning:

Ste Hughes:

Well you certainly have me confused.

The title of the thread refers to a 'sparkfun serLCD v2.5' which is an interface board that connects between a controller such as the Arduino and a standard 14 pin (or 16 pin if it has a backlight) parallel LCD module.

The link in reply #2 points to an LCD module that apparantly already has the serial interface permanently mounted and connected.

The link in reply #5 points to the pin assignment for a standard 14 pin (with 2 pin backlight) parallel LCD module. The photo in that same reply also shows a display with this type of parallel interface.

The display in the photo is the classic result you get when the LCD is properly powered but not properly initialized. In order to run this type of LCD over a parallel interface you need at least six wires, not counting power, ground, and LCD drive (contrast). From the photo it looks like the two white wires are the power and ground and I see a potentiometer so you have likely dealt with the contrast as well. I see only four more wires, two yellow and two green so you are missing two of the required interface wires, hence the uninitialized display. Also, with a six wire interface you must ground the R/W line (pin 5) of the LCD module.

How about showing us the sketch you are using?


? idk if im missing something but if you have the lcd linked to the sparkfun site, don't you simply need to connect gnd to gnd, vcc to vcc, and rx to the arduino's tx, and just use serial.print ( or serial.println perhaps ) and whatever you send should be on the screen? i believe that is how my lcd screen from sparkfun worked...

How did you know that the rx goes to tx of the arduino? I couldn't found any hints in the library or the datasheet to connect it right - so thx for your help!

How did you know that the rx goes to tx of the arduino?

It's usually a toss-up since most serial implementations don't follow the complete RS-232 specifications. Generally what is transmitted by one device must be received by the other device, hence the cross connection. If the complete RS-232 specification is implemented then one of the devices is deliberately mislabeled so that TX can be connected to TX and RX to RX.