I'll try to keep this simple.
I have a hub connected to my PC. This hub has several USB interfaces. I'm listening to WM_DEVICECHANGE event and I get the USB interface path. How can I know what port it was connected to? Looking for a non-WMI solution in c++ or c# for a windows environment.
I tried using IOCTL_USB_GET_NODE_CONNECTION_NAME with USB_NODE_CONNECTION_NAME (where USB_NODE_CONNECTION_NAME.NodeName will hold the path to the device) but this only works if the device connected to the port is a hub as well.
Any help will be much appreciated.
The primary issue in C++ is that there is no standard functions for detecting USB ports.
USB Port identification and implementation is a platform specific issue. For example, Linux handles USB ports quite differently than Windows and many embedded systems don't have USB ports.
So you'll have to look for a 3rd party library or find some OS API to use for your platform.
Related
I am trying to start using libusb for communication via COM port ( EDIT: for my Rs232 device), on windows 10 x64 only. My IDE is Code:blocks. I have a couple of questions:
I downloaded libusb from their website (latest windows binaries)
But I noticed there is a libusb-win32 ''version'' of it in sourceforge. It says
"libusb-win32 is a port of libusb-0.1 under Windows"
What does this mean, and should I use the "latest windows binaries" version or the "libusb-win32" version?
Also, the Readme file from their website (the 'libusb windows binaries' one) has instructions for compiling in Visual Studio and Mingw and there are files for Visual studio and Mingw only.
Does this means I cannot compile the libusb it in GNU GCC compiler?
EDIT: the question 2) is already answered here: https://stackoverflow.com/a/38252750/13294095
"I am trying to start using libusb for communication via COM port ( EDIT: for my Rs232 device), on windows 10 x64 only"
If you have a device that when you plug it into your PC via a USB port, it instantiates a COM port, then that device does have a UART. The device must also have driver that upon connecting to the PC is installed, and results in establishing the serial port you can see in device manager (under ports) Read about USB serial driver for some background.
"I have a physical uart device after the Rs232, I my MCU. I use the Rs-232 to translate from UART to USB protocol. -Even though I do not
know what "Virtual com port" is."
Your device may have a UART, but when you plug it into a PC via a USB port, a virtual serial port is created via a driver on the PC... "When the USB to serial adapter is connected to the computer via the USB port the driver on the computer creates a virtual COM port which shows up in Device Manager on Windows"... Read more here. (under Architecture)
In short, if when you plug your device into the PC, you can see a port that has been created in Device Manager, then all the work is done. Your application code can incorporate a C serial port library to open a port and send/receive serial messages, etc. However, if you are developing the device with the UART to work on a Windows PC via a USB port, then yes, you need to create a driver. Maybe then libUSB is for you.
I am writing a c++ program on my linux device where I can connect the device's micro usb to my computers (host) USB port. I want my program to detect if /dev/ttyGS0 has a device connected to it or not and if it does, I want my device to connect to it right away without having to send any data from my computer. And if it disconnects, I want it to also detect that and close the port. I do not want to use libusb for this. I want to use a different library.
As of now, I am using the fcntl.h library. I'm open to any other libraries and suggestions.
I plan to write serial driver to send data from target to host. The target is a renasas RX62N. And the host is windows 8.1. The target has RS232 port and the host has a USB port. I plan to use a converter cable with DB9(not sure) and USB connectors. 1) would like to know if I can send and receive from target and host? 2) would like to know if there is a way of getting around writing USB driver to send and receive from host is there software(Program) that could monitor usb port and send and receive dats over USB port? Ive seen software that let you send data and see the data receive by a port.
(1) RS-232 is bidirectional. You can send and receive at the same time.
(2) You do not have to write a USB driver for the host. Windows has this built in. Use the standard Windows serial I/O calls. They work the same way for serial ports and for USB to serial converters.
The USB<->RS-232 converter cable will appear to the PC host as a legacy serial port, support for the CDC/ACM USB profile that implements this port emulation is built into Windows, Linux and OSX. In windows however you will normally have to install "driver" which in most cases will simply be a INF file that maps the cable's USB vendor/product ID to the usbser.sys devive driver. Some USB/Serial devices may have custom drivers.
Common USB CDC/ACM devices from FTDI and Prolific will install drivers automatically via Windows Update (though historically Prolific drivers have been problematic - though recently they have improved).
At the target end, you communicate via the UART that is wired to the RS-232 line driver as you would normally.
For basic testing and keyboard/screen console access to your target, you van use any terminal emulator software such as TeraTerm, HyperTerminal, or Putty.
Previously I have work with Windows Form application to establish some RS232 connection. I used the already provided serial port component (SerialPort), and I was able to establish RS232 communication relatively easy.
Now, I was wondering if there will be something similar in Winodows Form application to establish a USB communication ?
It seems there is this WinUSB API that provides a very low level interfacing with the device.
However, I am not sure how easy will that be? Also, not sure how easy will it be to integrate into Windows Form application ?!
Will there be a simpler version of such USB interface API?
I don't have to stick to Visual Studio. Is there other c++ USB API, besides WinUSB, that is more standard that people use? I would like to develop a GUI API that does some communication over USB. If need be, I can use Python or some other tools if it facilitates the process?
Thanks in advance.
Although USB is a serial protocol, you can't treat USB like a serial port:
It's dependant on what the actual device is. For example a mobile phone, may provide several "endpoints" for USB, one being a serial port to use the phone as a modem, one as a storage device allowing you to transfer photos and music files to/from the phones storage, and as a camera device that you can take photos with. All of these have different behaviour and need a USB driver-plugin to make it behave correctly - these are typically shipped with Windows, and your phone will appear as COM5:, the E: or "Samsung Galaxy S3 Mini" drives and as a camera under the "cameras and scanners".
Of course, you can programmatically open all these devices, but it is done as the device-type that they present as on the inside of windows (so you use serial port functions or file functions or camera functions).
You CAN also write a device driver for a device, if you have sufficient details of how it works.
But there's no real way to "open the port". The USB API is a driver API, not a user-mode API. Here's a page to start from to understand USB drivers:
http://msdn.microsoft.com/en-gb/library/windows/hardware/ff540215%28v=vs.85%29.aspx
There is a WinUSB driver, which allows a single application to access a single device, assuming you know how to operate that device.
I have searched a lot and was unable to find the Answer for the Query.
I wanted to find out how many USB ports are available in PC, i.e like for serial port we have "COM1" and "COM2". My PC (windows7) contains 8 USB ports I need to find the list of ports along with whether they are used or not used.
I have tried using WMI query with no result as it gives details of only connected devices and USB hubs only.
With Win DDK it will display all the ports available with each HUB but interestingly that is not the same as I see from outside. Win DDK will give how many ports are addressable from each hub not the exact no of ports visible from outside. Any C or C++ code would be of great help.
The ideal result would be something like this:
USB 1 USED
USB 2 Not USed
USB 3 USED
USB 4 Not Used
.....
You cannot determine this. The simple reason is that you want to make a distinction between hubs inside your computer and hubs outside. It's likely that at least some of those 8 USB ports on your PC are linked to a hub soldered on your motherboard.
Also, it's not uncommon for USB to be used as an internal-only connection. E.g. many SD card readers are connected to an internal USB hub. To software, this looks like a USB port, but it's of course not visible on the outside of your PC.