I have a FTDI device which connects to ttyUSB0. After unplugging and re-inserting the device always connects to ttyUSB1. I have to detect the change and act accordingly to keep my send and recv functions running. I tried to detect it within the send and recv functions. Here is what I did:
`
def recv_serial_data(n):
global serial_port
try:
if not serial_port.isOpen():
serial_port = serial.Serial('/dev/ttyUSB1', 115200, 0.05)
data = serial_port.read(n)
tmp = []
for c in data:
tmp.append(ord(c))
print data
return tmp
except Exception, e:
raise Exception("recv_serial_data: " + str(e))
def send_serial_data(data):
print data,type(data)
global serial_port
try:
if not serial_port.isOpen():
serial_port.close()
serial_port = serial.Serial('/dev/ttyUSB1', 115200, 0.05)
if not isinstance(data, basestring):
data = array.array("B",data).tostring()
serial_port.write(data)
elif isinstance(data, basestring):
serial_port.write(data)
except Exception, e:
raise Exception("send_serial_data: " + str(e))
return
def main():
#[Doing stuff]
global serial_port
#options.serial_port is '/dev/ttyUSB0'
serial_port = serial.Serial(options.serial_port, options.baudrate, timeout=options.tty_timeout)
#[Doing stuff]
serial_port.close()
if __name__ == "__main__":
main()
`
What I get now are messages like "recv_serial_data: device reports readiness to read but returned no data" (device disconnected or multiple access on port?)" or "send_serial_data: write failed: [Errno 5] Input/Output error" As long as i don't unplug the device everything runs smoothly.
