I'm using node-serialport to work with USB devices, however on Windows I can't find out how can I connect to specific device. When I use list function there is only one item with COM3 address, however that is present always, even when no other devices are connected. How can I find out what is the USB device address that can be used for setting up communication?
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Two Linux machines (embedded board and PC) are connected to each other via USB cable, and communication is established via USB gadget/Ethernet. Both sides have IP address, ping works, etc.
I need to find a way to detect USB cable disconnect on the board side, ideally with a single Bash command.
ifconfig usb0 still shows IP address and that device is "UP" and "RUNNING" even after unplugging the cable.
In my particular case it turned out to be HW+SW issue: driver (atmel_usba_udc) is using USB power (VBUS) to detect connection, since it's acting as a slave and power is provided by host. However in PCB power is provided unconditionally by the board itself for all USB ports at once.
Normally any standard method should work: ifconfig or sysfs.
One way to do this is to check the file:
/sys/class/net/usb0/operstate
If the file content is "up" then the link exists. If the content is "down", then there is no link.
What I want to do:
An AI program on a host machine, reading inputs from a camera sensing the screen of the target machine and outputting controls to the target machine via USB connection--programming the host machine's USB host as a USB peripheral connected to the target machine.
What I want to do step by step: (is it possible to implement the steps below?)
Have a host machine A and a target machine B.
Connect A and B with a USB 3.0 Type-A male-male cable.
The USB connection shows up as an HID keyboard device on B.
Write code to simulate key presses on A that sends to B.
(Eg. calling press('F') on a program running on A would type F to B's input)
It shouldn't require any program installed on B.
What I already searched:
USB 3.0 Host to host connection is possible:
https://superuser.com/questions/795053/how-do-i-connect-two-computers-using-usb-3-0
USB 2.0 Host to host connection is impossible:
https://superuser.com/questions/99274/how-to-connect-two-computers-with-usb
Similar questions asked without the assumption that USB 3.0 Host to Host connection is possible:
https://superuser.com/questions/1128365/simulate-usb-keyboard-from-machine
Setting up a computer to act as an HID device connected to another computer via ps/2,usb or another wired connection
https://superuser.com/questions/507921/computer-to-act-as-keyboard?rq=1
Suggestions in ascending order of feasibility:
USB Gadgets
You are using linux, so the default way would be to create/configure/load a gadget driver. Have a look at this tutorial, though for a raspberry, should work on your PC too. However, I could not find any information regarding the use of USB3 - the tutorial assumes your host is using one of it's OTG ports, which your PC most likely does not have. So whether this works with your USB3.1 Type-A-to-Type-A connection you'll need to test.
USBIP
The idea of sharing USB devices (not just keyboards) is not really new. With USBIP you can "export" any local USB device to the network, and your client will need the client-side USBIP driver to access the keyboard.
Dont bother with USB at all, just use Ethernet
I'd simply write two userland scripts/programs that send/receive+execute the keystrokes. Very easy to implement, you're probably familiar with python anyway.
If you absolutely cant have software installed on the client-PC and your Type-C-to-Type-C connection doesnt support USB Gadgets, there's another way. It basically involves the use of two USB-to-serial adapters (~15$) and a serial cable. While this wont be enumerated as a keyboard, but rather as serial port, it's the lowest-effort solution to transfer data without additional software on the client. Both computers will just do file I/O. If your computers still have COM-ports, you can even omit the serial converters!
A method to Connect / Disconnect a USB device "softly".
Hey, Assume I have a USB device connected to my PC, I want to enable/disable the port it is connected via computer so that I don't have to unplug/plug my device each time.
P.S : Device is a Microcontroller Board ( powered by USB port ) , so I don't want it to be active all the time. I want to deactivate it when appyling changes to code etc. and then activate that port so I can load my code into it again.
Is there a method to do so ?
Thanks in advance.
Device is a Microcontroller Board ( powered by USB port )
Most USB enabled µC types can "unplug" themself.
The idea is to put the USB data pins (usually called D+ and D-) into "output low" state for about one second at startup. This forces USB to be recognized as "disconnected".
After that is done, re-configure the pins to for their USB function and initialze the USB as usual.
Note that this method is not possible on old style boards that still use USB2UART chips instead of hardware USB inside the µC itself.
I am new to working on virtual USB device simulation in Linux. So far I have installed the virtual host control (vhci) libraries as per this tutorial (http://sourceforge.net/p/usb-vhci/wiki/Home/) and can see a virtual USB device being created which has some typical specifications that the library implements (Bus 05 in the image with the vendor and product IDs being "dead" and "beef" respectively).
However I want the created virtual device to have the specifications of a real device I have at hand (a mouse, for example).
So how to enumerate and initialize a virtual USB device with the same credentials as another device?
The kernel module (vhci-hcd) is only a (virtual) host controller that you can attach virtual devices to.
If you want to emulate eg a mouse you should get the libusb_vhci from the same source, and look into the examples. These are bare minimum starting points that does nothing except for the basic usb device handling. You'll have to extend this with all descriptors and protocol handling for a USB HID mouse or whatever you want to emulate.
http://www.usbmadesimple.co.uk/ums_5.htm should be a good starting point.
you can use lsusb and in particular lsusb -D to dump the descriptors of devices you have connected.
I have multiple ACR122T smart card devices with no unique serial numbers (from ACS). I need to know which physical smart card I am connected to from within pcsc-lite. I know from using lsusb which USB Port a physical device is on, but how to map that USB port information with SCardGetAttribute(SCARD_ATTR_DEVICE_UNIT) ?
It seems the map should be at the OS level as I cant find a way to read USB Port info (lsusb results) from within the pscs-lite API.
This post mentions a method, Smartcard reader ACR122U has no unique serial number
but I dont understand the details behind "used that dev number to ensure I always used the right reader".
Any help appreciated.
Thanks, -Phil
Disclaimer: I'm working on Windows, not Linux.
The ACR122T (and ACR122U) devices not only have no serial number (other than the one printed on the back) but also have no USB serial number so that they can only be differentiated by the USB port they are plugged in. Additionally all the ACR122Ts and Us I have here (we bought a bunch) identify themselves as "ACS ACR122" to Windows. Using the proprietary API to get the firmware version both the ACR122T and the ACR122U identify themselves as a ACR122U (e.g. "ACR122U207" or "ACR122U214").
That means that the OS itself is not able to differentiate multiple devices in any other way then the USB port it's plugged in.
I also tried to make a connection between the pcsc device and the OS device, but apart from this function (which is only available starting Windows 8) I have not found anything, so it looks to me like there is no way to do that through pcsc calls.
The device unit is given out by the pcsc layer sequentially so you can differentiate between devices you are connected to but not identify a specific device.