I use arduino ide on arch linux with arduino uno connected via USB. I am sure that I choosed right port and board in ide menu. when I run ls -l /dev/ttyACM* I get:

crw-rw---- 1 root uucp 166, 0 14. dub 12.44 /dev/ttyACM0
crw-rw-rw- 1 root uucp 166, 1 14. dub 12.54 /dev/ttyACM1

but when I click upload I get this error:

Sketch uses 440 bytes (1%) of program storage space. Maximum is 32256 bytes.
Global variables use 9 bytes (0%) of dynamic memory, leaving 2039 bytes for local variables. Maximum is 2048 bytes.

avrdude: Version 6.3, compiled on Jul  7 2020 at 19:38:43
         Copyright (c) 2000-2005 Brian Dean, http://www.bdmicro.com/ 
         Copyright (c) 2007-2014 Joerg Wunsch

         System wide configuration file is "//etc/avrdude.conf"
         User configuration file is "/home/john/.avrduderc"
         User configuration file does not exist or is not a regular file, skipping

         Using Port                    : /dev/ttyACM1
         Using Programmer              : arduino
         Overriding Baud Rate          : 115200
avrdude: ser_open(): can't open device "/dev/ttyACM1": Input/output error

avrdude done.  Thank you.

the selected serial port 
 does not exist or your board is not connected

Error remains on newest linux kernel and LTS. --- My device is Lenovo thinkpad X390: Linux 5.11.14-arch1-1 --- When I plug arduino to usb and then run sudo dmesg I get this messages:

[ 1605.378324] usb 1-4: new full-speed USB device number 14 using xhci_hcd
[ 1605.520509] usb 1-4: New USB device found, idVendor=2341, idProduct=0043, bcdDevice= 0.01
[ 1605.520517] usb 1-4: New USB device strings: Mfr=1, Product=2, SerialNumber=220
[ 1605.520521] usb 1-4: Manufacturer: Arduino (www.arduino.cc)
[ 1605.520523] usb 1-4: SerialNumber: 7583434383935150E152
[ 1605.523881] cdc_acm 1-4:1.0: ttyACM1: USB ACM device
[ 1630.618749] usb 1-9: reset full-speed USB device number 10 using xhci_hcd
[ 1630.792727] audit: type=1130 audit(1618567069.016:82): pid=1 uid=0 auid=4294967295 ses=4294967295 msg='unit=fprintd comm="systemd" exe="/usr/lib/systemd/systemd" hostname=? addr=? terminal=? res=success'
[ 1632.601215] audit: type=1100 audit(1618567070.822:83): pid=29714 uid=1000 auid=1000 ses=1 msg='op=PAM:authentication grantors=? acct="john" exe="/usr/bin/sudo" hostname=? addr=? terminal=/dev/pts/1 res=failed'
[ 1635.720577] audit: type=1100 audit(1618567073.942:84): pid=29714 uid=1000 auid=1000 ses=1 msg='op=PAM:authentication grantors=pam_faillock,pam_permit,pam_faillock acct="john" exe="/usr/bin/sudo" hostname=? addr=? terminal=/dev/pts/1 res=success'
[ 1635.721507] audit: type=1101 audit(1618567073.942:85): pid=29714 uid=1000 auid=1000 ses=1 msg='op=PAM:accounting grantors=pam_unix,pam_permit,pam_time acct="john" exe="/usr/bin/sudo" hostname=? addr=? terminal=/dev/pts/1 res=success'
[ 1635.722751] audit: type=1110 audit(1618567073.946:86): pid=29714 uid=1000 auid=1000 ses=1 msg='op=PAM:setcred grantors=pam_faillock,pam_permit,pam_faillock acct="root" exe="/usr/bin/sudo" hostname=? addr=? terminal=/dev/pts/1 res=success'
[ 1635.727018] audit: type=1105 audit(1618567073.949:87): pid=29714 uid=1000 auid=1000 ses=1 msg='op=PAM:session_open grantors=pam_limits,pam_unix,pam_permit acct="root" exe="/usr/bin/sudo" hostname=? addr=? terminal=/dev/pts/1 res=success'

--- How can I fix this ? Thank you for help **PS:** If you need any more information, comment below and I will add it soon as possible.

I want to bind my Arduino Mega as /dev/ttyACM0. Sometimes, it turns out to be /dev/ttyACM0 and sometimes as /dev/ttyACM1. I have taken help from this question and this tutorial Someone please help me to achieve that as there are only 2 entries in /etc/udev/rules.d :- 1. 20-crystalhd.rules 2. 98-kexec.rules The output of udevadm info -a -p $(udevadm info -q path -n /dev/ttyACM0) :- > Udevadm info starts with the device specified by the devpath and then > walks up the chain of parent devices. It prints for every device > found, all possible attributes in the udev rules key format. A rule to > match, can be composed by the attributes of the device and the > attributes from one single parent device. looking at device '/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.5/2-1.5:1.0/tty/ttyACM0': KERNEL=="ttyACM0" SUBSYSTEM=="tty" DRIVER=="" looking at parent device '/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.5/2-1.5:1.0': KERNELS=="2-1.5:1.0" SUBSYSTEMS=="usb" DRIVERS=="cdc_acm" ATTRS{bInterfaceClass}=="02" ATTRS{bmCapabilities}=="6" ATTRS{bInterfaceSubClass}=="02" ATTRS{bInterfaceProtocol}=="01" ATTRS{bNumEndpoints}=="01" ATTRS{supports_autosuspend}=="1" ATTRS{bAlternateSetting}==" 0" ATTRS{bInterfaceNumber}=="00" looking at parent device '/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.5': KERNELS=="2-1.5" SUBSYSTEMS=="usb" DRIVERS=="usb" ATTRS{bDeviceSubClass}=="00" ATTRS{bDeviceProtocol}=="00" ATTRS{devpath}=="1.5" ATTRS{idVendor}=="2341" ATTRS{speed}=="12" ATTRS{bNumInterfaces}==" 2" ATTRS{bConfigurationValue}=="1" ATTRS{bMaxPacketSize0}=="8" ATTRS{busnum}=="2" ATTRS{devnum}=="4" ATTRS{configuration}=="" ATTRS{bMaxPower}=="100mA" ATTRS{authorized}=="1" ATTRS{bmAttributes}=="c0" ATTRS{bNumConfigurations}=="1" ATTRS{maxchild}=="0" ATTRS{bcdDevice}=="0001" ATTRS{avoid_reset_quirk}=="0" ATTRS{quirks}=="0x0" ATTRS{serial}=="55431313937351C05151" ATTRS{version}==" 1.10" ATTRS{urbnum}=="17" ATTRS{ltm_capable}=="no" ATTRS{manufacturer}=="Arduino (www.arduino.cc)" ATTRS{removable}=="removable" ATTRS{idProduct}=="0042" ATTRS{bDeviceClass}=="02" looking at parent device '/devices/pci0000:00/0000:00:1d.0/usb2/2-1': KERNELS=="2-1" SUBSYSTEMS=="usb" DRIVERS=="usb" ATTRS{bDeviceSubClass}=="00" ATTRS{bDeviceProtocol}=="01" ATTRS{devpath}=="1" ATTRS{idVendor}=="8087" ATTRS{speed}=="480" ATTRS{bNumInterfaces}==" 1" ATTRS{bConfigurationValue}=="1" ATTRS{bMaxPacketSize0}=="64" ATTRS{busnum}=="2" ATTRS{devnum}=="2" ATTRS{configuration}=="" ATTRS{bMaxPower}=="0mA" ATTRS{authorized}=="1" ATTRS{bmAttributes}=="e0" ATTRS{bNumConfigurations}=="1" ATTRS{maxchild}=="6" ATTRS{bcdDevice}=="0000" ATTRS{avoid_reset_quirk}=="0" ATTRS{quirks}=="0x0" ATTRS{version}==" 2.00" ATTRS{urbnum}=="70" ATTRS{ltm_capable}=="no" ATTRS{removable}=="unknown" ATTRS{idProduct}=="0024" ATTRS{bDeviceClass}=="09" looking at parent device '/devices/pci0000:00/0000:00:1d.0/usb2': KERNELS=="usb2" SUBSYSTEMS=="usb" DRIVERS=="usb" ATTRS{bDeviceSubClass}=="00" ATTRS{bDeviceProtocol}=="00" ATTRS{devpath}=="0" ATTRS{idVendor}=="1d6b" ATTRS{speed}=="480" ATTRS{bNumInterfaces}==" 1" ATTRS{bConfigurationValue}=="1" ATTRS{bMaxPacketSize0}=="64" ATTRS{authorized_default}=="1" ATTRS{busnum}=="2" ATTRS{devnum}=="1" ATTRS{configuration}=="" ATTRS{bMaxPower}=="0mA" ATTRS{authorized}=="1" ATTRS{bmAttributes}=="e0" ATTRS{bNumConfigurations}=="1" ATTRS{maxchild}=="2" ATTRS{bcdDevice}=="0310" ATTRS{avoid_reset_quirk}=="0" ATTRS{quirks}=="0x0" ATTRS{serial}=="0000:00:1d.0" ATTRS{version}==" 2.00" ATTRS{urbnum}=="42" ATTRS{ltm_capable}=="no" ATTRS{manufacturer}=="Linux 3.10.0-123.13.2.el7.x86_64 ehci_hcd" ATTRS{removable}=="unknown" ATTRS{idProduct}=="0002" ATTRS{bDeviceClass}=="09" ATTRS{product}=="EHCI Host Controller" looking at parent device '/devices/pci0000:00/0000:00:1d.0': KERNELS=="0000:00:1d.0" SUBSYSTEMS=="pci" DRIVERS=="ehci-pci" ATTRS{irq}=="23" ATTRS{subsystem_vendor}=="0x104d" ATTRS{broken_parity_status}=="0" ATTRS{class}=="0x0c0320" ATTRS{companion}=="" ATTRS{enabled}=="1" ATTRS{consistent_dma_mask_bits}=="32" ATTRS{dma_mask_bits}=="32" ATTRS{local_cpus}=="000f" ATTRS{device}=="0x1c26" ATTRS{uframe_periodic_max}=="100" ATTRS{msi_bus}=="" ATTRS{local_cpulist}=="0-3" ATTRS{vendor}=="0x8086" ATTRS{subsystem_device}=="0x9081" ATTRS{numa_node}=="-1" ATTRS{d3cold_allowed}=="1" looking at parent device '/devices/pci0000:00': KERNELS=="pci0000:00" SUBSYSTEMS=="" DRIVERS=="" ***Where should I edit my entries in which files and how. Please explain in somewhat depth as I am much naive!!*** Please help me establish this. It's already taking my mind and mood off.

I'm using socat to route serial input over a network to allow me to control an Arduino device over a virtual COM port setup. My command to start socat is: socat /dev/serial0,b500000,raw,echo=0 TCP-LISTEN:9876,nodelay,fork& This works the first time a device connects to the :9876 port perfectly fine. However, if the connection is dropped from the other end (which is using com2tcp on Windows), any further connections will send serial up the network to the RasPi hosting socat and out the serial device, but data will not be received in from /dev/serial0. I have to kill the original socat process, wait for the port to be released, and then re-run socat. Given the RasPi operates headless, this is an annoyance I'd rather avoid. Is there any way to allow multiple, non-simultaneous connections to work in this manner? I'm assuming there's some sort of setting to put in after the echo=0, but I can't figure out which one. (Further notes: the 500000 baud rate is required, as this is the rate required for the software I'm using, called GIMX. The purpose of this setup is to allow me to connect to a game console with devices in another room, using the remote play functionality to play the game. I have this command set in /etc/rc.local to start socat on boot, as the RasPi is also used as a media player using Volumio; this is simply running in the background.) ---------------------------------------------------- EDIT: I ended up abandoning the socat/com2tcp route, and implementing an RFC2247-compliant connection. This meant that I didn't have to worry about manually setting the baud rate as necessary, and seems to work in a more stable manner to boot. I based it on the information from https://robosavvy.com/forum/viewtopic.php?t=7578 which basically gives a full overview of setting it up. Although a couple of the links are dead, it has the information needed to get a connection going. I believe the command I was looking for was "end-close", however I did not test this before having committed to the new setup.

I have a device I'm trying to do some testing on. I know it connects at a baud rate of 115200, with 8 data bits, no parity and 1 stop bit. I'm attempting to prove these settings, or at least get close to showing these are in fact the settings the device is using. The device sends known data at startup, so the testing strategy is connect at correct setting to receive it, then vary a single setting and expect corrupted data. However, when I vary the parity or stop bit settings with pyserial or termios directly, I do not see corrupted data. Only variation to a data size of 6 bits corrupts the data. Is there any location or log where issues such a parity or stop bit errors could be recorded? Is there some setting using termios which can be tweaked to note errors with parity or stop bits? More data: Actual serial traffic is over a FT4232H in a USB-COM422-PLUS4 board, so the black box I'm looking to test shows up as /dev/ttyUSB3

I purchased a generic 8-pin ESP8266 off Amazon. It came loaded with some "AT" command firmware that acted like a modem. I connected the module to an FTDI1232 which is a USB connected UART that acts like a serial port. Here is the USB ID: Bus 002 Device 010: ID 0403:6001 Future Technology Devices International, Ltd FT232 Serial (UART) IC It appears as /dev/ttyUSB0 in my system. I installed CuteCom on my Ubuntu 14.04 machine, selected a speed of 115200, no parity, 8 bit characters and 1 stop bit. I was able to communicate normally to send and receive data using CuteCom. However, I don't really have much usage for this default firmware. I downloaded the latest version of Arduino IDE and then added in ESP8266 support via an additional core package. To program this device, I connected the ESP8266 based off this diagram. This is basically the circuit I already had, but I **had to add the RTS & DTR lines** to complete this. I created a very simple sketch like this void setup(){ Serial.begin(115200); // 8 bit char, no parity, 1 stop bit while(!Serial){}; } void loop(){ int v = Serial.read(); if(-1 != v){ Serial.write((uint8_t)v); }else{ delay(10) } } This is a basic "echo" type sketch that should write back whatever is written to the device. After uploading the sketch I can use the Tools -> Serial Monitor to interact with the sketch. I created a couple more, including one that transformed the data sent and then echo'd it back. They all work. At this point CuteCom, didn't work at all. After much searching for the reason, I eventually looked at the implementation of the Serial Monitor in the java code. What I found is this line !BaseNoGui.getBoardPreferences().getBoolean("serial.disableRTS"), !BaseNoGui.getBoardPreferences().getBoolean("serial.disableDTR")); From: https://github.com/arduino/Arduino/blob/ee1967cd530ceb9a1d638875e385157e90d532e8/arduino-core/src/processing/app/Serial.java#L68 It appears that basically each "board" (the nomenclature for the code that lets the SDK talk to the ESP8266 here) defines whether or not RTS & DTR should be enabled. The code then calls the jccs library to enable or disable RTS & CTS. At this point I disconnected the lines from my ESP8266 that were connected to RTS & CTS. I was able to use CuteCom again to talk to my new sketch I had uploaded. However, I don't want to have to disconnect & reconnect my lines each time I program from the Arduino IDE. Obviously it's possible to talk to the device without disconnecting them as the "Serial Monitor" in the Arduino IDE works just fine. How can I get a serial terminal emulator in Ubuntu 14.04 that will let me ignore RTS & DTR? I'd also accept commands to put the port in this mode so it can be used with socat or similar. It's probably irrelevant, but here is a photo of the actual devices

How do you enable hardware flow control for the Linux serial console? Perhaps using GRUB arguments? This post asks about specifying arguments to QEMU and GRUB to use the serial console, but doesn't address hardware flow control.

I'm using Ubuntu 25.04. My Arduino board creates a serial port on /dev/ttyACM0. When I try to upload a sketch using command line I get the following error: $ arduino-cli upload -p /dev/ttyACM0 --fqbn arduino:avr:leonardo sketch.ino Non è possibile effettuare il reset della porta: listing serial ports: lstat /dev/mqueue: permission denied avrdude: ser_open(): can't open device "/dev/ttyACM0": Permission denied Caricamento non riuscito: errore durante il caricamento: exit status 1 The device has the correct permissions: $ ls -l /dev/ttyA* crw-rw-rw-+ 1 root dialout 166, 0 giu 10 08:00 /dev/ttyACM0 and the current user has the dialout group: $ groups mark adm dialout cdrom sudo dip plugdev users lpadmin scanner vboxusers docker I removed the ModemManager application (it is known that could lead to this issue): $ sudo apt-get purge modemmanager I also checked that no other applications are using the same port: $ lsof /dev/ttyACM0 Any other applications (running as normal user) can open the port: CuteCom, cat, VSC, etc... **What can cause such an error given all the steps above?** UPDATE -- Running: $ journactl --follow give the following output after issuing the upload command: giu 10 08:38:36 mypc systemd: Started snap.arduino-cli.arduino-cli-538e4659-789a-4972-94e3-8d3dbe5dbf0a.scope. giu 10 08:38:36 mypc kernel: kauditd_printk_skb: 26 callbacks suppressed giu 10 08:38:36 mypc kernel: audit: type=1400 audit(1749537516.473:1519): apparmor="DENIED" operation="open" class="file" profile="snap.arduino-cli.arduino-cli" name="/snap/core/17210/usr/share/locale/it/LC_MESSAGES/snappy.mo" pid=42542 comm="snap-exec" requested_mask="r" denied_mask="r" fsuid=1000 ouid=0 giu 10 08:38:36 mypc kernel: audit: type=1326 audit(1749537516.672:1520): auid=1000 uid=1000 gid=1000 ses=2 subj=snap.arduino-cli.arduino-cli pid=42542 comm="arduino-cli" exe="/snap/arduino-cli/60/usr/bin/arduino-cli" sig=0 arch=40000003 syscall=434 compat=1 ip=0x8056dee code=0x50000 giu 10 08:38:36 mypc kernel: audit: type=1400 audit(1749537516.674:1521): apparmor="DENIED" operation="getattr" class="posix_mqueue" profile="snap.arduino-cli.arduino-cli" name="/" pid=42608 comm="serial-discover" requested="getattr" denied="getattr"class="posix_mqueue" fsuid=1000 ouid=0 giu 10 08:38:37 mypc kernel: audit: type=1400 audit(1749537517.677:1522): apparmor="DENIED" operation="getattr" class="posix_mqueue" profile="snap.arduino-cli.arduino-cli" name="/" pid=42542 comm="arduino-cli" requested="getattr" denied="getattr"class="posix_mqueue" fsuid=1000 ouid=0 giu 10 08:38:37 mypc kernel: audit: type=1400 audit(1749537517.683:1523): apparmor="DENIED" operation="open" class="file" profile="snap.arduino-cli.arduino-cli" name="/dev/ttyACM0" pid=42629 comm="avrdude" requested_mask="wr" denied_mask="wr" fsuid=1000 ouid=0 giu 10 08:38:37 mypc systemd: snap.arduino-cli.arduino-cli-538e4659-789a-4972-94e3-8d3dbe5dbf0a.scope: Consumed 295ms CPU time, 133.2M memory peak.

I am unable to write to or read from /dev/ttyS0 # cat /dev/ttyS0 cat: /dev/ttyS0: Input/output error the device exists, and root has permissions. # ls -lAhF /dev/ttyS0 crw------- 1 root root 4, 64 Nov 18 12:09 /dev/ttyS0 # setserial -g /dev/ttyS0 /dev/ttyS0, UART: 16550A, Port: 0x03f8, IRQ: 4 # dmesg | egrep -i 'serial|ttys' [ 1.243271] Serial: 8250/16550 driver, 1 ports, IRQ sharing disabled [ 2703.151301] ttyS0: LSR safety check engaged! # cat /proc/devices | grep tty 4 tty 4 ttyS 5 /dev/tty I have serial enabled in my kernel: # grep SERIAL config CONFIG_SERIAL_8250=y CONFIG_SERIAL_8250_NR_UARTS=1 CONFIG_SERIAL_8250_RUNTIME_UARTS=1 CONFIG_SERIAL_CORE=y **What do I have to do to make serial work ?**

I have a binary file(obtained from assembly code). I need to transfer this file to an fpga serially via ttyUSB0. I read in some posts that using cat and echo data can be transferred to ttyS0.

echo -ne '\033[2J' > /dev/ttyS1  
cat  < /dev/ttyS1

Does this apply for ttyUSB0 as well? If not, please suggest me other ways to transfer binary file via ttyUSB0.

I work with an RS-232 device via GNU screen. $ screen /dev/ttyUSB0 115200 At some point I need to send a local file to the device using either the xmodem or kermit protocol. On Windows I use TeraTerm which has a corresponding menu item. How can I achieve this in GNU screen?

I use Lightburn app to control CNC. The CNC controller has WIFI but the Lighburn can work only trough serial ports. So I found that I need to use socat to link cnc server from wifi to serial port. What Im doing (192.168.1.28:80 is a cnc server): socat PTY,link=~/dev/ttyS0 TCP:192.168.1.28:80 But get error: socat E symlink("/dev/ttys001", "~/dev/ttyS0"): No such file or directory And really, there is no /dev/ttys001 in /dev folder. What I'm doing wrong?

I have been trying to place two virtual machine with heartbeat. osboxes and osboxes2. When I run nmap localhost this is the output: Nmap scan report for localhost (127.0.0.1) Host is up (0.00017s latency). Not shown: 991 closed ports PORT STATE SERVICE 22/tcp open ssh 25/tcp open smtp 53/tcp open domain 80/tcp open http 443/tcp open https 631/tcp open ipp 3306/tcp open mysql 9050/tcp open tor-socks 10000/tcp open snet-sensor-mgmt Here is the tcpdump of such interface eth0: 18:38:22.267817 IP 192.168.141.135.48748 > 192.168.141.255.694: UDP, length 315 18:38:22.268640 IP 192.168.141.135.38234 > osboxes2.694: UDP, length 315 18:38:22.269421 IP osboxes2 > 192.168.141.135: ICMP osboxes2 udp port 694 unreachable, length 351 As you can see udp port 694 unreachable. When i try to ping osboxes from osboxes2: PING 192.168.141.137 (192.168.141.137) 56(84) bytes of data. 64 bytes from 192.168.141.137: icmp_seq=1 ttl=64 time=0.284 ms 64 bytes from 192.168.141.137: icmp_seq=2 ttl=64 time=0.291 ms 64 bytes from 192.168.141.137: icmp_seq=3 ttl=64 time=0.681 ms ha.cf file from osboxes: #Arquivo de log de debug: logfile /var/log/ha-log #Arquivo de log debugfile /var/log/ha-debug #Para onde vai os logs logfacility local0 #Frequencia em segundo de batimentos cardicados keepalive 2 #Tempo indica a morte do node deadtime 25 #Tempo que o heartbeat deve esperar por beats (nao o beat dos beatboxes) warntime 10 #Tempo maximo para declarar o outro servidor morto initdead 50 #Porto de sincronia udpport 694 #Endereco de broadcast da rede bcast eth0 #Nao entendi. Se for preciso vai la procurar depois. ucast eth0 192.168.141.137 #Determinar se o servidor volta para o master caso ele responda auto_failback on #Nome dos nodes do cluster node osboxes2 node osboxes haresourcers from osboxes: osboxes 192.168.141.135 apache It's worth noting that osboxes(principal node) is 192.168.141.135 and osboxes2 is 192.168.141.137. I guessing the problem resides in the port 694 not opened since it is unreachable.

I have a Wandboard IMX 6 with Android OS. I can't read RS232 data. I was wrote an app for this on QtCreator with C++. I have an issue. When i pressed the connect button i take serial port is being used for no permission to open error. I listed my available serial ports a dropdown menu. I can see ttymxc0 and ttymxc2 on dropdown but can't connect.

I'm following Altera's guide for running Linux on the DE1-SoC board, specifically section 5.3 - Installing the Driver. The instructions provided in the guide are for a Windows host, and I'm on a linux host (I don't currently have any Windows hosts available for permanent use). I'm following the instructions, but I can't get to ssh into the device, and I've exhausted all my efforts trying to troubleshoot it.

$ uname -r
5.15.0-124-generic

**To form a baseline, upon host startup, before ever connecting the board through usb:**

$ ls -al /lib/modules/"$(uname -r)"/kernel/drivers/usb/serial/usbserial.ko
-rw-r--r-- 1 root root 116161 Sep 27  2024 /lib/modules/5.15.0-124-generic/kernel/drivers/usb/serial/usbserial.ko
$ ls -al /lib/modules/"$(uname -r)"/kernel/drivers/usb/serial/cp210x.ko
-rw-r--r-- 1 root root 79865 Sep 27  2024 /lib/modules/5.15.0-124-generic/kernel/drivers/usb/serial/cp210x.ko

$ lsmod | grep cp210x
$ sudo modprobe usbserial
$ sudo modprobe cp210x
$ lsmod | grep cp210x
cp210x                 40960  0
usbserial              57344  1 cp210x

Meaning I've successfully loaded the driver.

$ dmesg | grep -i usb
...
[   30.186227] usb 2-3: current rate 16000 is different from the runtime rate 48000
[  124.301044] usbcore: registered new interface driver usbserial_generic
[  124.301067] usbserial: USB Serial support registered for generic
[  128.825043] usbcore: registered new interface driver cp210x
[  128.825069] usbserial: USB Serial support registered for cp210x

Corresponding to the loadings from above.

$ dmesg | grep -i tty
[    0.006788] ACPI: SSDT 0x0000000074487000 002357 (v02 ALASKA TbtTypeC 00000000 INTL 20200717)
[    0.117362] printk: console [tty0] enabled
[    0.401844] 00:01: ttyS0 at I/O 0x3f8 (irq = 4, base_baud = 115200) is a 16550A
$ lsusb
...
$ ls /dev/tty*
...

$ lsusb brings up a bunch of devices and $ ls /dev/tty* lists a bunch of terminals. The board is not showing of course, it's disconnected as I'm currently forming the baseline. **I now connect the board and turn it on.**

$ dmesg | grep -i usb
...
[  128.825069] usbserial: USB Serial support registered for cp210x
[  244.712211] usb 1-1: new high-speed USB device number 5 using xhci_hcd
[  244.860515] usb 1-1: New USB device found, idVendor=09fb, idProduct=6810, bcdDevice= 0.01
[  244.860527] usb 1-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0

idVendor and idProduct are identified correctly.

$ dmesg | grep -i tty[    0.006788] ACPI: SSDT 0x0000000074487000 002357 (v02 ALASKA TbtTypeC 00000000 INTL 20200717)
[    0.117362] printk: console [tty0] enabled
[    0.401844] 00:01: ttyS0 at I/O 0x3f8 (irq = 4, base_baud = 115200) is a 16550A

Nothing's changed.

$ lsusb
...
Bus 001 Device 005: ID 09fb:6810 Altera

This line is added. $ ls /dev/tty* Brings up exactly the same list - nothing's changed. As mentioned above, I'm out of ideas. I will appreciate any kind of help, so I can ssh to the board and start communicating between the ARM core and the FPGA.

So I have this issue with an USB to serial converter. On a fresh booted device it shows up as /dev/ttyUSB0 and I can connect to the serial device with minicom -D /dev/ttyUSB0. However, after some time (this could be minutes or hours, haven't figured out any trigger), the flow of data just stops. If I close minicom and try to start it again, I get the error minicom: cannot open /dev/ttyUSB0: No such file or directory. The device doesn't even show up in lsusb anymore. Unplugging / re-plugging doesn't help. I also re-soldered all the solder pads on the adapter to avoid connectivity issues but it didn't fix the issue. The only thing that fixes the issue is to reboot my computer. Which is maximum inconvenience in most cases because I have to close and re-open all the programs I'm working in. Any ideas what's happening here and how to fix it without closing all my open programs? Computer hardware is a ThinkPad T14 (first gen) with AMD processor. OS is Ubuntu 21.04.

I have a serial port device that I would like to test using linux command line. I am able to use stty and echo for sending commands to serial port, but when device responds I have no way of reading what is coming from serial port. I am using `stty -F /dev/ttyS0 speed 9600 cs8 -cstopb -parenb && echo -n ^R^B > /dev/ttyS0` to send a command to the device. Device operates and sends a response back in 300 ms's. How do I print that response to the console using command line?

In Linux, is it possible to use a *local* serial port? Something similar to this: ssh user@localhost I tried this on Raspbian but it doesn't work (it should place in my shell but it doesn't): microcom -d /dev/ttyAMA0 I also tried /dev/ttyS0 but to no avail. I can of course access Raspberry Pi through serial console from *another* machine. There is no specific use-case for this question - I just cannot understand how really serial works. If it's possible to connect to the localhost with ssh shouldn't it be also possible with serial port?

I have a question regarding the ports in Linux. If I connect my device via USB and want to check its port I can't do it using the command lsusb, which only specifies bus number and device number on this bus: [ziga@Ziga-PC ~]$ lsusb Bus 003 Device 007: ID 0403:6001 Future Technology Devices International, Ltd FT232 USB-Serial (UART) IC **Is there a command that tells me the port the device is connected to directly?** Only way to do this until now was to disconect and reconnect and using the command: [ziga@Ziga-PC ~]$ dmesg | grep tty [ 0.000000] console [tty0] enabled [ 0.929510] 00:09: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A [ 4.378109] systemd: Starting system-getty.slice. [ 4.378543] systemd: Created slice system-getty.slice. [ 8.786474] usb 3-4.4: FTDI USB Serial Device converter now attached to ttyUSB0 In the last line it can be seen that my device is connected to **/dev/ttyUSB0**.

I am working on an embedded Linux system (kernel-5.10.188), and use /dev/ttyS2 as serial console and ash in busybox is the login shell. After logging in to system, I ran top -d 1 in the serial console (I am using mobaxterm in Windows 11 to acess the serial console), it worked well. Then I closed PC's lid (Windows suspended itself). A few minutes later, I resumed the PC and found the serial connection in mobaxterm is down, I typed 'R' to re-connect the serial console, but there is NO output from the serial console. I login to the system through adb shell, and I got followings. * top -d 1 is process of PID, its status showed

Name:   top
Umask:  0022
State:  S (sleeping)
Tgid:   345
Ngid:   0
Pid:    345
PPid:   210
.....
voluntary_ctxt_switches:        51
nonvoluntary_ctxt_switches:     22

The last two lines showed the same value when cat /proc/345/status for several times. So the process is not running. By running cat /proc/345/stack, it showed following.

# cat /proc/345/stack
[] wait_woken+0x74/0x94
[] n_tty_write+0x480/0x4f0
[] file_tty_write.isra.36+0x1c8/0x358
[] vfs_write+0x3e8/0x4d8
[] ksys_write+0xe0/0x124
[] syscall_common+0x34/0x58

The process is waiting in vfs_write and n_tty_write (I think it is from something printf or puts from top utility). I can killed the top process with kill -9 345. But there is still NO response in the console, so I checked the login shell process. * Check the process of 210 (the login shell and the parent of top).

# cat /proc/210/status
Name:   sh
Umask:  0022
State:  S (sleeping)
Tgid:   210
Ngid:   0
Pid:    210
PPid:   1
......
voluntary_ctxt_switches:        236
nonvoluntary_ctxt_switches:     45

# cat /proc/210/stack
[] wait_woken+0x74/0x94
[] n_tty_write+0x480/0x4f0
[] file_tty_write.isra.36+0x1c8/0x358
[] vfs_write+0x3e8/0x4d8
[] ksys_write+0xe0/0x124
[] syscall_common+0x34/0x58

The login shell is also in vfs_write and not being scheduled. I have to kill -9 210 to bring back the login shell. I can definely reproduce this issue with Windows suspend/resume. I went through the long list of kernel's commits on tty, but I did NOT find the same issue or the fix. So what is the cause of this hang in serial console and how to fix it? Or where should I post this issue or bug for help?

I have this usb-serial device: root@imx6_armboard:/etc/udev/rules.d# udevadm info -a -p $(udevadm info -q path -n /dev/ttyUSB0) Udevadm info starts with the device specified by the devpath and then walks up the chain of parent devices. It prints for every device found, all possible attributes in the udev rules key format. A rule to match, can be composed by the attributes of the device and the attributes from one single parent device. looking at device '/devices/platform/fsl-ehci.1/usb2/2-1/2-1.1/2-1.1:1.0/ttyUSB0/tty/ttyUSB0': KERNEL=="ttyUSB0" SUBSYSTEM=="tty" DRIVER=="" looking at parent device '/devices/platform/fsl-ehci.1/usb2/2-1/2-1.1/2-1.1:1.0/ttyUSB0': KERNELS=="ttyUSB0" SUBSYSTEMS=="usb-serial" DRIVERS=="ftdi_sio" ATTRS{latency_timer}=="1" ATTRS{port_number}=="0" looking at parent device '/devices/platform/fsl-ehci.1/usb2/2-1/2-1.1/2-1.1:1.0': KERNELS=="2-1.1:1.0" SUBSYSTEMS=="usb" DRIVERS=="ftdi_sio" ATTRS{bInterfaceNumber}=="00" ATTRS{bAlternateSetting}==" 0" ATTRS{bNumEndpoints}=="02" ATTRS{bInterfaceClass}=="ff" ATTRS{bInterfaceSubClass}=="ff" ATTRS{bInterfaceProtocol}=="ff" ATTRS{supports_autosuspend}=="1" ATTRS{interface}=="FT232R USB UART" looking at parent device '/devices/platform/fsl-ehci.1/usb2/2-1/2-1.1': KERNELS=="2-1.1" SUBSYSTEMS=="usb" DRIVERS=="usb" ATTRS{configuration}=="" ATTRS{bNumInterfaces}==" 1" ATTRS{bConfigurationValue}=="1" ATTRS{bmAttributes}=="a0" ATTRS{bMaxPower}==" 90mA" ATTRS{urbnum}=="30409" ATTRS{idVendor}=="0403" ATTRS{idProduct}=="6001" ATTRS{bcdDevice}=="0600" ATTRS{bDeviceClass}=="00" ATTRS{bDeviceSubClass}=="00" ATTRS{bDeviceProtocol}=="00" ATTRS{bNumConfigurations}=="1" ATTRS{bMaxPacketSize0}=="8" ATTRS{speed}=="12" ATTRS{busnum}=="2" ATTRS{devnum}=="9" ATTRS{devpath}=="1.1" ATTRS{version}==" 2.00" ATTRS{maxchild}=="0" ATTRS{quirks}=="0x0" ATTRS{avoid_reset_quirk}=="0" ATTRS{authorized}=="1" ATTRS{manufacturer}=="FTDI" ATTRS{product}=="FT232R USB UART" ATTRS{serial}=="A400CZBK" looking at parent device '/devices/platform/fsl-ehci.1/usb2/2-1': KERNELS=="2-1" SUBSYSTEMS=="usb" DRIVERS=="usb" ATTRS{configuration}=="" ATTRS{bNumInterfaces}==" 1" ATTRS{bConfigurationValue}=="1" ATTRS{bmAttributes}=="e0" ATTRS{bMaxPower}==" 2mA" ATTRS{urbnum}=="15513" ATTRS{idVendor}=="0424" ATTRS{idProduct}=="2513" ATTRS{bcdDevice}=="0bb3" ATTRS{bDeviceClass}=="09" ATTRS{bDeviceSubClass}=="00" ATTRS{bDeviceProtocol}=="02" ATTRS{bNumConfigurations}=="1" ATTRS{bMaxPacketSize0}=="64" ATTRS{speed}=="480" ATTRS{busnum}=="2" ATTRS{devnum}=="2" ATTRS{devpath}=="1" ATTRS{version}==" 2.00" ATTRS{maxchild}=="3" ATTRS{quirks}=="0x0" ATTRS{avoid_reset_quirk}=="0" ATTRS{authorized}=="1" looking at parent device '/devices/platform/fsl-ehci.1/usb2': KERNELS=="usb2" SUBSYSTEMS=="usb" DRIVERS=="usb" ATTRS{configuration}=="" ATTRS{bNumInterfaces}==" 1" ATTRS{bConfigurationValue}=="1" ATTRS{bmAttributes}=="e0" ATTRS{bMaxPower}==" 0mA" ATTRS{urbnum}=="48" ATTRS{idVendor}=="1d6b" ATTRS{idProduct}=="0002" ATTRS{bcdDevice}=="0300" ATTRS{bDeviceClass}=="09" ATTRS{bDeviceSubClass}=="00" ATTRS{bDeviceProtocol}=="01" ATTRS{bNumConfigurations}=="1" ATTRS{bMaxPacketSize0}=="64" ATTRS{speed}=="480" ATTRS{busnum}=="2" ATTRS{devnum}=="1" ATTRS{devpath}=="0" ATTRS{version}==" 2.00" ATTRS{maxchild}=="1" ATTRS{quirks}=="0x0" ATTRS{avoid_reset_quirk}=="0" ATTRS{authorized}=="1" ATTRS{manufacturer}=="Linux 3.0.35-02671-gb0836db ehci_hcd" ATTRS{product}=="Freescale On-Chip EHCI Host Controller" ATTRS{serial}=="fsl-ehci.1" ATTRS{authorized_default}=="1" looking at parent device '/devices/platform/fsl-ehci.1': KERNELS=="fsl-ehci.1" SUBSYSTEMS=="platform" DRIVERS=="fsl-ehci" looking at parent device '/devices/platform': KERNELS=="platform" SUBSYSTEMS=="" DRIVERS==" I tried to create a rule for this in /etc/udev/rules.d/99-usbserial-sensors.rules. this one SUBSYSTEM=="usb-serial", KERNEL=="ttyUSB?", ATTRS{serial}=="A400CZBK", SYMLINK+="sensO2" I spent a **WHOLE** day, looking into documentation and running udevd and udevadm in debug mode trying to figure out why did this rule not work as expected. In the end (of the day), this rule worked: SUBSYSTEMS=="usb", KERNEL=="ttyUSB?", ATTRS{serial}=="A400CZBK", SYMLINK+="sensO2" so basically, i used the clause SUBSYSTEM**_S_**=="**usb**" instead of SUBSYSTEM="usb-serial". and the question is WHY did it work? Why doesn't usb-serial trigger the udev daemon. Especially when it is there exactly so that one can grab it with udevadm info??? Thank you