CM3-Panel-7-poe technical documentation

How to configure serial port adapters on the USB port (Multiple Hub)

Now we connect the serial port adapter, and run command:

$ lsusb

Result:

Bus 001 Device 006: ID 0bda:8153 Realtek Semiconductor Corp. RTL8153 Gigabit Ethernet Adapter
Bus 001 Device 008: ID 067b:2303 Prolific Technology, Inc. PL2303 Serial Port
Bus 001 Device 005: ID 2109:2813 VIA Labs, Inc. 
Bus 001 Device 003: ID 0424:ec00 Standard Microsystems Corp. SMSC9512/9514 Fast Ethernet Adapter
Bus 001 Device 002: ID 0424:9514 Standard Microsystems Corp. SMC9514 Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

This ID is the serial port adapter where, 067b is idVendor and the second number 2303 is idProduct.

Launch this command:

$ udevadm info /dev/ttyUSB0 | grep "ID_PATH="

Result:

pi@panel7:~/app $ udevadm info /dev/ttyUSB0 | grep "ID_PATH="
E: ID_PATH=platform-3f980000.usb-usb-0:1.4.2:1.0

The string "platform-3f980000.usb-usb-0:1.4.2:1.0" must be inserted into a file through this command:

$ sudo nano /etc/udev/rules.d/99-usb-serial.rules

This is content:

ENV{ID_PATH}=="platform-3f980000.usb-usb-0:1.4.2:1.0", SUBSYSTEM=="tty", ATTRS{idVendor}=="067b", ATTRS{idProduct}=="2303", SYMLINK+="ttyS01", GROUP="dialout", MODE="0666"

Now disconnect the adapter and reconnect to the same port.

Now we’ll have a new serial device called /dev/ttyS01.

To view this test more quickly, we can use this Python script:

Run command:

$ pip install termcolor

Launch this command:

$ nano /home/app/serialmonitor.py

Insert:

#!/usr/bin/python

import time
import os
import serial.tools.list_ports as ports
from termcolor import colored, cprint   # ( Require --> pip install termcolor )


while True:
    time.sleep(.2)

    os.system("clear")

    print "===================================================================="
    cprint(' FIX SERIAL USB ADAPTER - PORT MONITOR', 'blue', attrs=['bold', 'blink'])
    print "===================================================================="

    ser_ports = list(ports.comports()) # List serial port

    cprint('\nUSB Serial Port device:', 'blue', attrs=['bold', 'blink'])

    for i in ser_ports:    
        vn = i.device
        p = time.strftime("%Y-%m-%d %H:%M:%S") + "\t" + vn

        if ( vn.find('ttyS') > 0 ):
            cprint(p + ' - (Use this port)', 'green', attrs=['bold'])
        else:
            cprint(p, 'red', attrs=['bold'])


    cprint('\nSimlink Serial Port:', 'yellow', attrs=['bold', 'blink'])
    os.system("ls -la /dev/tty* | grep \" ->\"")

    time.sleep(.2)

Run this command:

$ chmod +x /home/pi/serialmonitor.py

Now, to run the script run the following command:

$ ./home/pi/serialmonitor.py

Result:

====================================================================
 FIX SERIAL USB ADAPTER - PORT MONITOR
====================================================================

USB Serial Port device:
2021-09-14 16:30:33  /dev/ttyS01 - (Use this port)
2021-09-14 16:30:33  /dev/ttyUSB0
2021-09-14 16:30:33  /dev/ttyAMA0

Simlink Serial Port:
lrwxrwxrwx 1 root root          7 Sep 14 16:30 /dev/ttyS01 -> ttyUSB0

CM3-Panel-7-poe technical documentation