Nextion displays.

[AndrewC]

Hi
Anybody have any luck in getting one of these Nextion displays to work with a MicroChip PIC micro-controller using flow code?

I did find an example in the Russian Flowcode area. But Google translate doesn't quite cut it and I can't access the example.

But at $20 for a 3.2 inch screen, it interests me.

Cheers
Andrew

[Benj]

Hi Andrew,

This reminds me a lot of the 4D Systems VISI interface, you design the GUI and then control/monitor the GUI using the serial VISI command interface.

The Nextion seems to do the same thing but without the open source VISI interface, unless I am missing something.

Either way I've not found a API document explaining how the Nextion interface works so it could be it's closed source and will only work with their software?

[Benj]

Aha, found an Arduino libraruy now.

https://github.com/itead/ITEADLIB_Arduino_Nextion

Might be possible to craft a Flowcode component for this. I will keep investigating.

[AndrewC]

Hi Andrew,

This reminds me a lot of the 4D Systems VISI interface, you design the GUI and then control/monitor the GUI using the serial VISI command interface.

The Nextion seems to do the same thing but without the open source VISI interface, unless I am missing something.

Either way I've not found a API document explaining how the Nextion interface works so it could be it's closed source and will only work with their software?

Hi Ben.

It does seem to 'resemble' the 4D Systems interface but you get what you pay for. After a brief play with the GUI it does not seem to be so refined, you have to go looking for, or create, your own graphics for such objects like a gauge, unlike 4D Genie where you are spoon fed the graphics. Nextion seem to provide just the pointer.
I like the 4D Systems products but they are a bit expensive to chuck on every project but for $14US I can now.

Re: "I've not found a API document explaining how the Nextion interface works so it could be it's closed source". I found an answer on the forum about making it open source a year ago - "There is not such plan at current stage. "

Anyway I have decided to order the 2.4" to have a play. I managed to get the Flowcode example from the Russian Flowcode site. Unfortunately it's for ATMEGA8 but it may give me a starting point.

[ressi]

Hello. Do you have a solution on how to receive data from the display and evaluate? I want a motor on, but I can not figure out how I can receive data correctly. Does anyone have a solution? Data can I write correctly in the display. I wanted to register on the Russian Flowcode page but can not get access.
I appreciate any solution Bin !!!

[Benj]

Hello,

I've looked at the Arduino example again but I'm struggling to know the right way to do this.

Can you share the Flowcode example or the Russian website where you are finding the information and I will see what we can do with this.

[AndrewC]

Hi guys.

Apologies for not replying ressi. I'm not really sure how it's done (complete novice) as I have yet to receive my display so don't want to lead you in the wrong direction talking gibberish. Also I don't know why you can't register on the site. I had no problems apart from the expected using Google translate like this phrase "These are the moments of the pancake." OoooKaaaayy!

The link in the first post should take you there. But here's the web address.

http://flowcode.info/forum/viewtopic.php?f=19&t=2135

And here's the file Benj. I wasn't sure about posting some one else's work. I hope it helps and it's what we need.

nextion_mega8_v6.fcfx

(27.37 KiB) Downloaded 900 times

Cheers
Andrew

[Bachman]

I think, the best way using this displays as a normal display. Do everything by the controller, reading from the display only the touch event, nothing more. Reading by UART interrupt, sending data as normal UART communication, easy to use.

Sedning "12345" text to object t0:

Code: Select all

SendRS232String("t0.txt=")
SendRS232Char(34)  //quotation mark
SendRS232String("12345")
SendRS232Char(34)
SendRS232Char(255)
SendRS232Char(255)
SendRS232Char(255)

The display send "A0", "A1" or "A2" if you touch an object. Receiving it by UART interrupt:

UART Interrupt.jpg (59.32 KiB) Viewed 24166 times

As you see, not necessary to send lots of characters by the display, if you using only some touchable object, the data can be only one byte long.

This two projects created in Flowcode, using only UART commands and UART (RS232) interrupt:

Nextion HMI 1.jpg (41.28 KiB) Viewed 24166 times

Nextion HMI 2.jpg (32.85 KiB) Viewed 24166 times

[AndrewC]

Thanks Bachman. That's a great help, just what I was looking for.

Mine has just arrived so I've now got a starting point and can now play.

[Bachman]

Highly recommended, start testing the display via an USB - UART converter. Much-much faster. You can test the commands (with your program in the display), if everithing is ok, write the microcontroller program. Whit this procedure, you can thest the display first. Othervise, you won't know where is the problem if you find one (or more).

FTDI USB - UART.png

(191.99 KiB) Downloaded 13103 times

[dazz]

Hi Bachman
Thanks for the info i will have a play later, One thing i would say is if anyone orders one, make sure you order an adaptor as in bachman's post.
I had one but i can't find it, so if you have a spare arduino laying around you can use that till you get an adaptor.

There are a couple of ways to do this the easiest way is to simply connect the arduino's Reset to ground, connect it to your hmi display (5v,gnd,tx,rx)
the other way is to upload the following as a sketch using the arduino ide, that was theres no need to tie the reset to gnd. im using a spare nano for this

Code: Select all

void setup(){
  pinMode(0,INPUT);
  pinMode(1,INPUT);
}
void loop(){
}

Regards
Dazz

[gordonschlag]

hi guys new here and not a programmer. I have read the above info and would like to know if there has been any luck with a module for the nextion displays. If it is in the works let me know
when it is completed so that i can purchase it. I have some displays and wold like to use flowcode to program them ,there ide is not what i would call good but I would call it poor but usable. may be you could talk with Patrick Martin at itead and work with him on a module for flow code. As for the display it is awesome and has a lot of potential . one of the best things about it is that ,the display handles all the screens . so you don't have to have the arduino draw them. They are pictures stored on the display and called by touch events and maybe even data passed on the serial line. But if the you have the enhanced version you have gpio lines that can trigger events or screens and the fields in the screens can have there info updated by passing data from the arduino to the display by way of the serial line. I hope this made sense and I don't look or sound like a 10th grade drop out (which I am )...

[schutki]

I think that the crucial thing is to understand in what format messages are sent to Nextion display to change some variable/text value and in what format you send values back to Uart (it can be Microcotroller/PC..).

I made one short tutorial here to show this formats using RS232 terminal (It can be any serial port terminal program such as Docklight, teraterm, bray...)

http://www.electronics-base.com/feature ... r-projects

I hope it helps a bit to understand it. And as you can see do not forger to send 3 times 0xff or byte value (255) or otherwise command will not be processed

[AbhijitR]

Hello! Bachman

Sedning "12345" text to object t0:

Code: Select all

SendRS232String("t0.txt=")
SendRS232Char(34)  //quotation mark
SendRS232String("12345")
SendRS232Char(34)
SendRS232Char(255)
SendRS232Char(255)
SendRS232Char(255)

Was struggling for sometime.

Thanks for this post, cheers.

Abhi