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pySerial - missed messages - Printable Version

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pySerial - missed messages - q_nerk - Jan-25-2022

ESP32 is sending data via USB do desktop with Ubuntu 20.04 (at the end script will be used on RPI4).
Yesterday it was working, today not.

def read():
    port = '/dev/ttyUSB0'
    baudrate = 115200
    ser = serial.Serial(port, baudrate)
    data = ser.readline()
    text = data.decode(errors="ignore")
    return text
What serial monitor from arduino ide see:
Output:
x0.33
y0.76
z9.70
t0.19
x0.32
y0.73
z9.73
t0.19
x0.31
y0.74
z9.65
t0.19
....
What is terminal output from script:
Output:
x0.27

z9.71

x0.26

z9.73

x0.29

z9.72

x0.29

z9.68

x0.28

z9.73

x0.28

z9.70

x0.28

z9.74

x0.20

z9.74

x0.33

z9.69

x0.29

z9.68
....
The funniest thing is that it was working yesterday, today is not. What I'm doing wrong? I tried to set different timeout, as well as None, and many other parameters with no result.

RE: pySerial - missed messages - deanhystad - Jan-25-2022

I don't know what happens when you repeat this over and over on an already opened serial port.
ser = serial.Serial(port, baudrate)
Does this close the already open connection? If so, that would flush anything remaining in the read buffer. I would open the port once and read many times.

RE: pySerial - missed messages - Jeff_t - Jan-27-2022

Can you post the section of serial output code of the ESP32 so that we can see what your python script should expect and if there is a better way to read it.