Video tutorial displays NEXTION

the description of Nextion exchange mentions 8 available GPIO ports.
How to use them? (from nextion's page)

Menu-> Help-> Instruction Set
Everything is there

Is it possible to validate the values entered into the number field from the nextion level?
e.g., only a range of 0 to 500

You probably can. In one video I showed how to choose the keyboard operation code. You can modify it to do validation.

Eh ... I had to add (declare) another 10 controls to the project and I crashed into a wall of missing memory in arduino nano:

... "The sketch uses 9058 bytes (29%) of program memory. Maximum is 30720 bytes.
Global variables use 1594 bytes (77%) of dynamic memory, leaving 454 bytes for local variables. The maximum is 2048 bytes.
Low available memory, may experience stability problems ... "...

in total, that's 35 controls.
Can it be remedied or optimized?

darlin wrote:

Global variables use 1594 bytes (77%) of dynamic memory

A large project for a nano. On the other hand, if we only estimate 4 bytes (or as many as 4) for a variable, then 398 variables come out.
Don't you have any large declared arrays in the global?
Subtract some control from the project, preferably the one you have the most, and enter how much has decreased. As it will be known what control is, you can combine something here. Although without the code ...

Subtract 10 controls of type NexNumber Pos1 = NexNumber (0, 4, "set.n0"); that's 10% of memory recovered
subtracting the next 9 NexCheckbox Check = NexCheckbox (2, 13, "set.c0"); is the next 7% recovered
In both cases I don't need 4 bytes per variable. NextChecbox is only two bits after all. A numeric would suffice to uint16_t.

darlin wrote:

"set.n0"

I think in one of the films I said something about the influence of the name length on the RAM occupancy (maybe it was live). On the one hand, long names are cool, but on the other hand, they have to be remembered because the nextion library matches objects by name, not by ID (sucks a bit, but it is).

darlin wrote:

NextChecbox is only two bits after all

why?

Object names have a huge impact on the size of the memory allocation, so I use at most two characters. Second thing, if the communication with both people on the display is only one way (no callback), do not define the object in Nano, but send data with short Serial.println ending 3x FF transmissions, it will also save you a lot of memory. In the afternoon I'll throw in a sample function if you want.

Greetings

Thanks for your guidance. You can see that something else can be done. I will also be happy to see the function.

As a last resort, you can get rid of the bootloder is some extra 4KB
but the suggestion of Serial.print and names may solve my problem. I will check and let you know.

as for NextChecbox 2 bits - no matter - I mixed up something (;

darlin wrote:

suggestion Serial.print and names maybe will solve my problem.

You can use the library functions without creating objects, as Sławek wrote.


Giving up the bootloader will only save in program memory. Either the application or the bootloader is running.

Examples of functions below:

1. Sends a float number to a textbox in Nextion



2. Sends the text to a text field in Nextion


3. Sends an int to the numeric field in Nextion



4. Sends a system command to Nextion

Greetings

We managed to save some memory with the above methods, but we would like more (;.
I wonder if the following conversion to uint8_t has the right to work?

nP1.getValue (uint8_t (& storeData [1] .pos));
nC1.getValue (uint8_t (& storeData [1] .ch));

the compiler admits something like this cautiously:
warning: cast from 'uint8_t * {aka unsigned char *}' to 'uint8_t {aka unsigned char}' loses precision [-fpermissive]

but it seems to be working.
Maybe some suggestion in this direction?
Basically all these 35 values of nextiona controls I have to write to arduino eeprom.

Gentlemen, I have been sitting for a long time to run Nextion with ESP32 on Serial2, everything I managed to achieve is one-way communication ESP >> nextion, unfortunately I have no idea how to master nextion

When I send a command from the level of arduno to nextion using Serial, for example:
Serial.print ("thsp = 1");
Serial.print ("\" \ xFF \ xFF \ xFF ");
All other nextion objects stop being sent, and in the show preview I see something like this:
???Bkcmd = 1???page 0??????????????????????????????????????? ???????????????????????????????????? ...
???????????????Thsp = 1 "????????????

When I comment on Serial.print, the others show up:
???Bkcmd = 1???page 0???s1.n0???s1.n1???s1.n2???s1.n3???s1.n4???s2.n0??? s2.n1???s2.n2???s2.n30???s2.

Can't both ways work in parallel?

And what kind of arduino?

nano and works on one series

Without the code, it will be hard to help.
A library function that sends looks like this

First it clears the input buffer. But that's the way I shoot without the code.

With "thsp = 3" it also doesn't work. Generally my problem concerns all commands sent by serial.
But I already know what's going on.
This is an ailment that I described a few posts earlier, and which I still struggle with, not being able to develop anything else in the program.
It's about the permanent lack of memory for global variables in my nano. .. "Global variables use 1827 bytes (89%) of dynamic memory" ..
When I freed up my memory a bit, the serial command and nextion object commands started working.

I came up with a slightly different way of communication. Using the already existing number field. In arduino, I send a numeric field, e.g. value 5.
I watch in the nextion timer and if the field has this value, I turn it off
thsp = 3
thup = 0
only that it doesn't quite want to work (;

it only works when I change the value from 5 to another.

.. "leaving 221 bytes for local variables".
So far, the program without serials works.

Hello everyone, I got interested in this display thanks to the videos found on YouTube of the Author of the topic, I wanted to do something similar to the episode 18 with the DS18B20 thermometer.
There is a moment when the numeric keyboard is set under the text field, when I open the debugger after connecting to the arduino, the displayed keyboard flashes and descriptions disappear, e.g. 1,2,3, 4, etc. it should work like that otherwise it gets the code
1A FF FF FF
Can anyone help me with this?

It's hard to call it a project because it's more of the beginning of fun and testing, I hope it can be downloaded

I checked this mentioned fragment 10 times, there was actually a mistake but correcting didn't change anything the keyboard still starts flashing and code 1A pops up when I select it

Okay, different, I wanted to write a code that reads the temperature from several thermometers and have a field to set the value, e.g. for the first thermometer, where if I enter, for example, 23 degrees, the diode next to the arduino will light up after crossing.

There is something wrong in the rewritten code from the guide, I have the impression that it is about text fields, not numeric ones, but I can't deal with it too much.

could I count on somebody's help?

or maybe someone works on ESP32? I have compile errors all the time and cannot configure Nextion

In the Nextion.h file, find:
#include NexUpload.h
and comment:
// # include NexUpload.h

Greetings