Prox / RFID
Ladder Logic
[interfacing] †
Tube Joints
Key Code From Photo
SolveSpace (3d CAD)
SketchFlat (2d CAD)
Resume / Consulting
Contact Me


(you are viewing a thread; or go back to list of threads)

NEXTION TOUCH (by Ihor Nehrutsa)
Has anyone tried to connect Nextion touch screen to the LDmicro?
Is there a practical result and experience?

Wed Aug 22 2018, 07:52:45
(no subject) (by Tom J.)
I have sent uart to a PIC from one.
Nextion sends three 4-character codes to signify the end of a transmission.
I wrote a ladder to try to isolate and filter them but can't tell what's happening, theres formatting somewhere and my LCD displays a different value than the Nextion is sending.

I'm going to try to send the UART right back to the Nextion and display it there to look for clues.

I have with great success used the Nextion GPIOs to send binary 16 bit and display the numeric value on 7-segment with PIC. Theoretically I could use the other four lines to send binary back to the Nextion.
Sat Feb 2 2019, 11:18:26
(no subject) (by Tom J.)
Ihor, I've had limited success with serial, my test is a PIC16F886 and a serial enabled LCD.
So far I can get the LCD to display but it's often just "255".
According to the Nextion instruction set:

"All instructions over serial: are terminated with three bytes of 0xFF 0xFF 0xFF
ie: decimal: 255 or hex: 0xFF or ansichar: ˙ or binary: 11111111
ie byte ndt[3] = {255,255,255}; write(ndt,3); or print(“\xFF\xFF\xFF”); or print(“˙˙˙”) "

That explains the "255" so I'm currently working on a filter to catch a certain number of characters (what I'm actually sending) and then disregard the termination bytes and then I think we're in business at least with receiving data from the Nextion.
Have you had any success?
Sun Feb 10 2019, 13:57:51
(no subject) (by Tom J.)
This is what I have so far, The first section is attempting to ring count the string and break it down byte by byte.
The second section moves the bytes one at a time to variable SEND.
The third section sends the contents of variable SEND to LCD in order so I can see what's there.

The ladder is well commented, I believe the first section is not breaking the data stream down into individual bytes.
Sun Feb 10 2019, 17:16:32, download attachment SerialTest2.ld
(no subject) (by MGP)
Tom, take a good look at this code, how you can get a string or number.

Mon Feb 11 2019, 09:03:43
Post a reply to this comment:
Your Name:
Your Email:
(no HTML tags; use plain text, and hit Enter for a line break)
Attached file (if you want, 5 MB max):