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Nextion String Keypad, receiving string in Arduino

Hey! I hope i dont 'break' the rules again Mr. Patrick! :)

I'm using Nextion Display Basic 3.5"

Arduino Mega 2560

no aditional libraries except for the Nextion.h

I see there is some people in here having trouble to get values from nextion and receive in arduino. I was in there too, cause i'm not an expert in C code. Then i come with a simple solution you can adapt to whatever, i think.

First you need to read the documentation about the data return of nextion displays. For the example i'm using a text component to send ASCII characters through serial.

for this the nextion returns:

0x70 -> indicate the data type is ASCII characters in HEX

0xXX -> bytes for the ASCII chars

0xFF |

0xFF |_> Transmission END

0xFF |

Well, now its simple, you use a button(or any touch event) on nextion that executes the command:

get t0.txt

and it will send through serial the bytes for the text in t0.txt

so, in arduino, you read the string on the serial, and by testing the index 0 of the string, you determinate what kind of data the nextion sent.

after, you need to know where the data ends ( 3 x 0xFF)

in this case, i used a String function that returns the index of the first 0xFF.


and use this index as reference, because the lenght of this data will depend on the numbers of characters.

and just concatenate the bytes between index 0 and the index of first 0xFF.

simple as that!

The commented .ino code and HMI file is attached. I hope I can help someone with this and contribute to the community.

1 Comment

sorry, but breaking "rules" is nothing I even can smile about ... :-)

anyway, thanks for your contribution ... we need more of such ...

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