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Message #24779

e4rthdog

Posts: 10

Can i connect 2 LCD 20x4 displays (I2C) and handle them from MF?

I have seen the solution of having 2 pages of info and maybe i will follow this if i cant have 2 LCDs connected.

Thanks.

2022-01-03 20:34

Message #24781

Whiteknuckle157

From: Bayern - Bibertal, Germany

Posts: 50

Yes, you can.
Connect them as advised for I2C (may need pull up resistor). Change address on one module and set the address in mobiflight.

cheers

2022-01-04 00:03

Message #24782

e4rthdog

Posts: 10

So you mean something like this for wiring and just change the address in one of the LCDs?

2022-01-04 08:17

Message #24785

pizman82

Moderator

From: ETSI, Germany

Posts: 6010

Supporter

e4rthdog:
Can i connect 2 LCD 20x4 displays (I2C) and handle them from MF?

Yes and "maybe No" .....

Basically .... You can Handle Hundrets of LCD 20x4 if you like.... The Number of Arduino Megas is not limited by MF (Only by windows) ..... So if you need e.g. 10 Displays and you use 10 Megas ( 1 Display each) .... Then this work without any disadvantage !

*************

Whatever ... Lets talk about the Limitations and Whiteknuckles Comment and your linked Picture

Correct!
Mobiflight allow up to TWO LCD Devices per one Arduino Board .
Setup as you expect.... Both share the SDA,SCL Pins and both must be set ( mostly by jumpers on the I2C Controler) to two DIFFERENT Adresses.
In MF you finally create 2 Devices and choose for there correct Adress.

PROBLEM:
In the past (Prior current 9.2) there was a "buffer overflow" that occure in freezing LCD´s .... specially if TWO of them was in use on one Board.
Sebastian fix this as i know.... So e.g. 2x 16x2 is now possible without trouble.
BUT
I´m not sure if the Buffer still is enough if you use two large 20x4 ( That would need ~~200 byte of Buffer) .
(( @Seb... You can comment this yourself ))
*************

I recommend:
If you plan with only one Mega..... You can try it. It "should" work .... And it work garantee with 2 smaller Displays... With large ones i´m not sure

If a second Mega and a USB Hub is no problem to you ( may you still plan for multiple Megas and a lot of Buttons/LED) then i would set only One Display per Board.
This work 100% Confirmed without problems !

Good Luck !

2022-01-04 12:11

Message #24788

e4rthdog

Posts: 10

pizman82:
Hi
I recommend:
If you plan with only one Mega..... You can try it. It "should" work .... And it work garantee with 2 smaller Displays... With large ones i´m not sure

If a second Mega and a USB Hub is no problem to you ( may you still plan for multiple Megas and a lot of Buttons/LED) then i would set only One Display per Board.
This work 100% Confirmed without problems !

Thank you very much. That was what i was looking for.. I will start with one mega and 2 LCDs and if i get issues i will just add a second Mega...

I am receiving my stuff tomorrow so i will be getting onto it soon enough.

2022-01-04 14:23