Pyserial 1 second delay

Projects Networking, Protocols, and Devices
1

Hello,

I am not quite sure if this is the place to put this question, but I am having issues with using pyserial to send commands to my arduino GIGA R1. I am trying to rapidly send USB commands (aiming for 1 command every 0.3 seconds) via string over USB connection that looks like this "i2,xxxx,xxxx,xxxx,xxxx" to change the output on an i2c DAC. I know I can change the DAC pretty rapidly in a loop solely on the R1 (rapidly switching between 2 values every 40ms) and the code takes 1ms to execute when a command is received via Serial monitor. However, when I try to do the same via pyserial, I have to set a delay of just over 1 second for it to work. If less than that, the DAC just wont change. Is this caused by code under the hood of how pyserial works? Or is there something else going on? Baud is set to 250000, buffer on the COM port in device manager is reduced to 1, and the baud rate is also at the max for the com port

2

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3

Impossible to say without seeing your sketch code and Python script.

There may be some wrong input parsing or buffering or timeouts or wrong line endings in place.

4

I've written a small tutorial on interfacing with Python. See Two ways communication between Python3 and Arduino

that feels like a timeout

If you create a Ser##ial object without specifying the timeout parameter, then reads are blocking and will wait indefinitely until enough data arrives. if you have copied some code from somewhere else, may be

serial.Serial(
    port=None,
    baudrate=250000,
    bytesize=EIGHTBITS,
    parity=PARITY_NONE,
    stopbits=STOPBITS_ONE,
    timeout=None,    # <<==== ⚠️⚠️what do you have there ??
    write_timeout=None,
    inter_byte_timeout=None
)