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pythonserial-portnextion

Connecting RS232 to Serial and establishing a connection to Nextion display from a python script

I was trying to establish a serial communication between my python script and Nextion display. I want to create a custom firmware uploader, so I could use it instead of Nextion Editor.

Unfortunately I can't establish a connection to the screen(RS232 to Serial is connected properly and detected, I use default 9600 baud rate). After sending

  DRAKJHSUYDGBNCJHGJKSHBDNÿÿÿ
  connectÿÿÿ
  ÿÿconnectÿÿÿ

It should respond properly... I found a document from Nextion that explains the Upload Protocol: https://nextion.tech/2017/12/08/nextion-hmi-upload-protocol-v1-1/

And here is my script, that produces from time to time

b'$\xff\xff\xff'

import serial
from time import sleep
ser = serial.Serial('/dev/tty.usbserial-A94RJPXT',9600,timeout=0)
ser.write(str.encode("  DRAKJHSUYDGBNCJHGJKSHBDNÿÿÿ"))
ser.write(str.encode("\n"))
ser.write(str.encode("  connectÿÿÿ"))
ser.write(str.encode("\n"))
ser.write(str.encode("  ÿÿconnectÿÿÿ"))
ser.write(str.encode("\n"))

while True:
        print(ser.readline())
        sleep(0.1)

WORKING CODE:

import serial
from time import sleep
ser = serial.Serial('/dev/tty.usbserial-A94RJPXT',9600,timeout=0)

ser.write("DRAKJHSUYDGBNCJHGJKSHBDNÿÿÿ".encode('iso-8859-1'))
ser.write("connectÿÿÿ".encode('iso-8859-1'))  # could try some other encodings
ser.write("ÿÿconnectÿÿÿ".encode('iso-8859-1'))

while True:
        data=ser.readline().decode('iso-8859-1')
        if data !="":
                print(data)
        sleep(0.1)
Solution

  • If you look at this GitHub commit, you'll see that they do:

    this->sendCommand("DRAKJHSUYDGBNCJHGJKSHBDNÿÿÿ");
this->sendCommand("connectÿÿÿ");
this->sendCommand("ÿÿconnectÿÿÿ");

    That suggests that you do not need the spaces or newlines. If that doesn't work, you should also consider different encodings (and make your current encodings explicit):

    ser.write("DRAKJHSUYDGBNCJHGJKSHBDNÿÿÿ".encode('utf-8'))
ser.write("connectÿÿÿ".encode('utf-8'))  # could try some other encodings
ser.write("ÿÿconnectÿÿÿ".encode('utf-8'))