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[on:]

Hi.
Please tell me how many 20X04 with serial interface works in parallel on arduino mega 2560?
I'm very confuse from this line code:
LiquidCrystal_I2C lcd(0x27 20,4); //set the LCD address to 0x27

All lcd from this model has an internal address 0X27 or i can use some like this:
LiquidCrystal_I2C lcd1(0x27 20,4);
LiquidCrystal_I2C lcd2(0x28 20,4);
LiquidCrystal_I2C lcd3(0x29 20,4);
LiquidCrystal_I2C lcd4(0x30 20,4);
If the answer is yes how it works , how i know with lcd is for 0X27 , witch for 0X28....

Many thanks.

[Reply #1 on:]

I'm in the same boat man...read my 20 x 4 LCD post using the Uno......

I'm not familiar with the atmega 2560, just the Uno....but are you getting any type of any display on the LCD...not just the white pixels?

[Reply #2 on:]

Please tell me how many 20X04 with serial interface works in parallel on arduino mega 2560?
I'm very confuse from this line code:
LiquidCrystal_I2C lcd(0x27 20,4); //set the LCD address to 0x27

In order to answer your question we would have to know more about the specific I2C interface chip and its implementation by the designer of the PC board on which the chip is mounted.

Don

[Reply #3 on:]

...read my 20 x 4 LCD post using the Uno......

In order to do this we would need a link to the post. 

Go to the post in question and right click on the icon that looks like two sheets of paper, just to the left of the 'subject'.  Select 'Copy Link Location' (or something similar) and then paste that information into your reply.

Don

[Reply #4 on:]

Post a link to the serial display you have/want to buy.

[Reply #5 on:]

this is what i want to use
http://www.ebay.com/itm/Serial-IIC-I2C-TWI-2004-204-20X4-Character-LCD-Module-Display-For-Arduino-Blue-/180940569952?pt=LH_DefaultDomain_0&hash=item2a20e5fd60

many thanks

[Reply #6 on:]

The way that particular board is set up there is no way to change the I2C address so you are stuck with the one that they have configured, 0x27.

I can't tell what chip is being used but some I2C interface chips have one or more 'address' pins making it possible to select two or more addresses.  If that chip is one of them then it is conceivable that you could rework some of the traces on the PC board and change the address.  This is not a trivial operation but it is not impossible either.

Don

[Reply #7 on:]

Many thanks for your answer.

[Reply #8 on:]

FYI, my design: up to 255 displays can be connected to one serial port.

http://www.inmojo.com/store/liudr-arduino-and-physics-gadgets/item/serial-lcd-back-pack---phi-panel/