serial write can't do it myself

[ricardons]

hello I'm having a lot of difficult to connect to serial port

I've a device that communicates by serial (Nextion HMI) with my raspberry pi via UART

I have this python file to read the port that works

serial_read.py

import serial

ser = serial.Serial(

    port='/dev/ttyAMA0',
    baudrate=9600,
    parity=serial.PARITY_NONE,
    stopbits=serial.STOPBITS_ONE,
    bytesize=serial.EIGHTBITS,
    timeout=1
)

while 1:
    x = ser.readline()
    print(x)

When i push a button in my tft screen i get

b'e\x06\x01\x00\xff\xff\xff'

this has a meaning (that i know)

the problem is that i want to do the opposite that is: write in the port the same command

so i've write this

serial_write.py

import time
import serial

ser = serial.Serial(

    port='/dev/ttyAMA0',
    baudrate=9600,
    parity=serial.PARITY_NONE,
    stopbits=serial.STOPBITS_ONE,
    bytesize=serial.EIGHTBITS,
    timeout=1
)

while 1:
    y='e\x06\x01\x00\xff\xff\xff'
    ser.write(y)

but it does not work. I don't get anything when i run serial_read.py
it seems that i'm not sending anything
what's wrong?
help is appreciated

[Larz60+]

this has a meaning (that i know)
OK, so you know what the meaning is?
do tell

[ricardons]

I didn't think it would be helpful

https://nextion.itead.cc/resources/docum...ction-set/

0x65 7 Touch Event 0x65 0x06 0x01 0x00 0xFF 0xFF 0xFF


Returned when Touch occurs and component’s
corresponding Send Component ID is checked
in the users HMI design.
0x06 is page number, 0x01 is component ID,
0x01 is event (0x01 Press and 0x00 Release)
data: Page 6, Component 1, released

[Larz60+]

I didn't think it would be helpful

Perhaps you're correct, at least on a high level. I have interfaced to
simpler devices, and knew that there are a series of commands that
must be sent, correctly, in proper order, before anything would be
seen on the device.
From the Nextion Instruction set manual:

Note: Nextion will remain waiting at step 5 until every byte of specified quantity is received.

so I suspect this is why you're not seeing anything

Have you seen this: https://github.com/g4klx/MMDVMHost
This appears to be a complete interface to one of their displays.

Another page http://vorsselmansphilip.blogspot.com/20...-test.html

and one final:
http://www.marrold.co.uk/2017/03/adding-...mhost.html

[ricardons]

thanks
I will have a look