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+--- Thread: Multiple process access to a serial port (/thread-17512.html)
Multiple process access to a serial port - mkonnov - Apr-14-2019
Hi all,
I need to implement the multiple process access to a serial port.
Do anybody implemented that ?
My code call will look like the following:
[bash]
python3 xbee_process_1.py &
python3 xbee_process_2.py &
python3 xbee_process_3.py &
[/bash]
For now, without of multiprocess support, the single process looks like this:
from digi.xbee.devices import XBeeDevice
xbee = XBeeDevice('/dev/ttyUSB0', 9600)
xbee.open()Obviously, when I'm using this code in each process, they start to interfere with each other and see the different serial port errors.I know that XBeeDevice contains the XBeeSerialPort as one of its dependencies and contains ._serial_port instance as a descriptor for the serial port.
So I'm going to implement my own serial port instance with necessary process locks and rewrite the ._serial_port instance:
from xbee_device_wrapper import xbee_device_wrapper
xbee = xbee_device_wrapper('/dev/ttyUSB0', 9600)from digi.xbee.devices import XBeeDevice
from digi.xbee.serial import XBeeSerialPort
import traceback
class serial_port_proxy(XBeeSerialPort):
def __init__(self, baud_rate, port, **kwargs):
super().__init__(baud_rate, port, **kwargs)
def open(self):
print("\n-----------", traceback.extract_stack())
return super().open()
class xbee_device_wrapper(XBeeDevice):
def __init__(self, port, baud_rate):
super().__init__(port, baud_rate)
self._serial_port = serial_port_proxy(baud_rate, port)
self.open()