Asked — Edited

Re: I2c Help

Hi DJ,

In your i2c help, you mentioned that the address is 7 bits correct me if i'm wrong but if you've got bit 0-7 then isn't it 8 bits?

Let me explain:

bit 0 - 1 bit bit 1 - 1 bit bit 2 - 1 bit bit 3 - 1 bit bit 4 - 1 bit bit 5 - 1 bit bit 6 - 1 bit bit 7 - 1 bit

You see? in total, you've got 8 bits now.

Edit: wait i'm confused blush please delete this thread.....


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DJ, Did you ever get a chance to mess around with the i2c LCD. Mine just sits there being blue. "Hello world" would be awsome.


I tried, lots. But those lcd's have zero documentation. Without documentation, i'm shooting in the dark. There is a combination of hundreds of addresses and commands to guess from. Thousands actually. I know why they're so cheap now!



I found this arduino code:


LiquidCrystal_I2C lcd(0x27,16,2); //set the LCD address to 0x27 for a 16 chars and 2 line display

void setup()
    lcd.setCursor(0, 0);
    lcd.print("hello world");
    lcd.setCursor(0, 1);
    lcd.print("hello world 2");

I bet you will find out how to do it if you decompile the LiquidCrystal library.

Also @Bookmaker what LCD do you have?


I've looked at the library. We've tried the 0x27 address. The issue is these no-name i2c lcd's have no documentation so we don't even know what address they are, or if they've even compatible with that library.


You could try with an arduino first, i'm afraid to ask, but do you have one laying around?


I looked in the turorials and don't see anything on how to program the Serial ones. Are they ease for a none nerd like me? I want to replace the i2c one and get the LCD up and running. Iyron, you are welcome to my old one.


I may have found the solution. i2c LCD forum It states some ways down the they shipped the wrong library with the LCD and they give a url for the correct one. Naturly I don't have the vaguest idea what they are talking about however you may.

correct library


@Bookmaker Yes, serial LCDs are so much easier, i have a sparkfun one that i got up and running in less than 10mins.

Anyways, Good luck with the library you found! If you need any help, hit me up.


Lyron, I don't know anything about i2c much less the library. May be DJ can give us a hand here?


@Bookmaker LINK:I2C SCL : Clock SDA : Data

clock is used to notify which device is going to be master in order to ship data across the I2C bus also to notify data: 1's and 0's.