I want to write code that will allow me to send a command (not just video) from a computer to a TV, specifically, a command that will change the input. The code needs to be in C++, and the communication must be done through a usb cable.
I am currently using Qt to communicate with the ports, but the only port that I can communicate with is "com1". I was wondering, how do I get the names of the usb ports that devices like my mouse, usb sound adapter, etc are currently using?
And if there is any Qt code that lets me send commands to usb devices, that would be sick.
Just because USB means Universal Serial Bus, doesn't make every USB device a serial port.
USB devices have different classes, handled by different drivers. Human interface input devices like mice and keyboards are of a HID class. These devices are not serial ports, and will not appear on a list of serial ports. Same goes for a majority of other popular devices such as scanners, video cameras, etc.
The only devices that will appear on a list of serial ports are communications class devices (CDC), and USB-to-serial converters that have drivers that expose them as serial ports, like e.g. FTDI chips.
As for your TV, you need to figure out what kind of a device class your TV appears as. You would use a tool like usbview to enumerate USB devices and see their properties. Your TV could even be a composite device that has a HID class device, and some other device class.
Related
I'm trying to capture video from usb webcam, what is connected to a certain usb port (I have many same cameras connected). I have a code that makes USB Device Path for all webcams. I have something like:
\\?\usb#vid_0c45&pid_614a#5&18f54cb7&0&2#{65e8773d-8f56-11d0-a3b9-00a0c9223196}\global
Where: 5&18f54cb7&0&2 - USB serial string. I cant use pid and vid because I have other same webcams.
How can I get usb port and hub knowing USB serial?
The hub is the parent of the webcam, so you find it via SetupDiGetDeviceProperty property DEVPKEY_Device_Parent. USB port is DEVPKEY_Device_LocationInfo.
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'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.
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.