Serial port not blown properly

Question

I have an RPi (Yes, I know, maybe someone thinks this belongs to the RPi site, but I think that it is related to Linux as a whole, so StackOverflow is the right place) and I talk between some Arduinos over MAX485 using Python3 and pySerial . This works more or less, because I found that I need to make some kind of weird workaround so that everything works "correctly."

If I send data using:

GPIO.output(23, 1) # Pulling transmit pin high to send
comport.write("Some data".encode()) # Writing data
comport.flush() # Flushing the buffer
GPIO.output(23, 0) # Pulling pin down to receive

Arduino receives the data and responds immediately, but since pySerial is somehow not ready yet, it does not return anything and we have a lost packet.

However, if I try like this:

GPIO.output(23, 1)
comport.write("Some data".encode())
time.sleep(.001) # Add some delay of only 1ms
comport.flush()
GPIO.output(23, 0)

. : flush? :

GPIO.output(23, 1)
comport.write("Some data".encode())
time.sleep(.001) # Add some delay
# -- No flush --
GPIO.output(23, 0)

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Answer 1

pyserial write_timeout timeout ( ), , , .

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Answer 2

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, Moxa Half Duplex 485 RS-485

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, RS-485, Full Duplex, RS-422 , , RS-232.