How to access USB port using pySerial (Windows)? - windows

I am trying to open USB port in Python (using pySerial). I ran port listing tool, but it only shows COM ports. I'd like to open USB port instead (trying to communicate with tablet, but that's not relevant, I suppose). I know it is possible (and quite easy) on Linux, but I am on Windows 8, so there's nothing like "/dev/tty...".
I'd like to show you some of my code, but I can't, because I have none yet (I need to know how to open USB port to be able to start coding, I am just testing yet).
Maybe I will have to install some other module, but I'd rather just stay with pySerial, if it's possible.
Can anyone help me with opening USB port?

Related

Listing USB Ports on a PC

I'm coding C/C++ on an Arduino to communicate with a Node.js server over the serial port using the serialport Node.js package. I have written this code on a Mac. In my Node.js code I need to reference the USB port, for reference mine is:
/dev/tty.wchusbserialfa14
On a Mac, to get a list of ports in a format that will work in my Node.js code I use the terminal and this command:
ls /dev/{tty,cu}.*
I can not find the equivalent for a Windows computer. Could someone please tell me what the command is to list the ports on a Windows machine, in a format that I can use in my Node.js.
Thanks!
Edit: Added more context about use of ports
You are searching not USB ports, but serial ports. Because you are using USB to serial converter that build in Arduino, and looking about serial ports. How to get list of serial ports in windows you can find here or in google.
Excuse me, can't comment yet.
Thanks for your help! The following command gave me a list of ports in a format that will work in my Node.js code:
chgport

How to communicate with the USB Host from a Linux USB Client

The host part will be a PC program made from c# in which I will use LibUSBdotnet to do the communication.
My problem is how do I make the Linux side pickup and respond. I don't really know where to start.
Whenever I try to search for it, all result show are "how linux communicates with a device attached to it".
Or it does not matter if a device is host or client, because they utilize the same pipes/bus?
Can I use something in "/dev/usb***"?
I have seen "libusb" which I believe is the linux cousin of libusbdotnet.
Can I somehow use this library? If anyone can show me the right direction, I would really appreciate it.
AFAIK libusb is the library for usb-host side, not for usb-device side. So you cannot use it in your case. I suggest the same as myninjaname said - to analyse one of the Linux usb gadget drivers as a start point.

How can I make a custom USB device show up in Windows as a COM Port?

I have developed a USB device that communicates with linux over a simple but proprietary interface and some custom Linux drivers. My goal is to port this to Windows without writing windows drivers. What I would like to do is find an open source or inbuilt class driver for windows that would look like a COM port in Windows. Then I would tailor the embedded software to match what ever protocol and descriptors the virtual COM port expects to see.
The idea would be that I could plug my device in to a Windows machine and a relatively high speed COM port would appear with out me having to develop Windows drivers for it.
I have been looking at the USB CDC (Communications Device Class) documentation and it looks promising, but I don't know which sub interface would be best to use so that it would show up as a COM port.
Has anyone here done any work like this before or could provide some insight?
Specifically:
Are there virtual COM drivers "built in" to windows or would I need a 3rd party driver.
Which CDC sub class should I use for simple RS232 emulation (No need for modem AT commands, etc)
Is there a better option to do what I am trying to do.
Thanks
There is a USB-to-serial driver built in to Windows that will do what you want. It is called usbser.sys:
http://support.microsoft.com/kb/837637
You will have to write an INF file and distribute that to your users, but that will not be too hard because it is only a few kilobytes of text and you can find examples online.
I'm not aware of any great documentation for this driver by Microsoft, so my advice would be to find some other device that uses it, such as Pololu Wixel, and copy what they did.
Here are the device descriptors we used and the special control tranfers we had to implement:
https://github.com/pololu/wixel-sdk/blob/master/libraries/src/usb_cdc_acm/usb_cdc_acm.c
You can see our INF file, wixel_serial.inf, by downloading the software and looking in the drivers folder:
http://www.pololu.com/docs/0J46/3.a
(There are other files in there that are not necessary for you.)
You can also look at the Arduino Uno because they use the same driver.
Whatever you do, please don't use our USB Vendor ID in your product! You need to get your own.
Update: In Windows 10, you don't need an INF file anymore because of the new usbser.inf driver that comes with Windows.
If you are using a UART you can easily interface it to a FTDI USB chip like http://www.ftdichip.com/Products/ICs/FT232R.htm or a Prolific like http://www.prolific.com.tw/eng/products.asp?id=59
For development, prototype and testing I have half dozen of these laying around http://www.pololu.com/catalog/product/391
I connect it directly to the UART pins on AVR and 8051 micros.

Configuring 2 XBee Modules on OSX for wireless connection

I am trying find out how and with which program for OSX (10.5.8) I can configure serial ports? I am trying to establish a wireless connection between two Xbee´s (RF modules) and cannot figure out how to use ZTerm nor screen under Terminal. The setup I am using is: an Arduino+Xbeeshield+Xbee with external power supply, and an xbee on the xbee explorer connected to the Computer via USB.
I am trying to gather information on this through various forums, but most of them cover the configuration issue for PC using X-CTU (which I tried with CrossOver but it doesn´t recognize ny of my ports). According to one source, using screen under Terminal should show me all my serial ports, particularly /dev/tty.KeySerial1 - but it doesn´t show, even though I´ve plugged in both my arduino+xbee shield and the xbee on the explorer.
/dev/tty.KeySerial1 is incorrect.
First step is to get the FTDI USB driver installed if it has not yet been installed. The fastest way to determine if it is installed or not is to connect the XBee Explorer board. Then go look in /dev for a device named tty.usbserial-XXXXXXXX (Xs will be a unique hex ID). If you see multiple devices like this, then you probably have the Arduino plugged in too and you will need to disconnect it to determine what the device name is for the XBee Explorer board.
Once you know the device name, all you need to do is the command "screen /dev/tty.usbserial-XXXXXXXXX 9600". That should do it for you.
You can configure the tty device itself using stty. Be sure to redirect input from the terminal you want to configure, as stty operates on it's input. For instance, to set a serial port to 9600, no parity, 8 data bits, and 1 stop bit, aka "9600N81" in Windows parlance, try:
stty 9600 cs8 -cstopb -parenb < /dev/tty.usbserial-xxxxxxxx
Programmatically, you do this by opening the serial port and using the termios(4) ioctls on the device. See the termios(4) man page for more assistance.

Faking an RS232 Serial Port

I'm developing a project that has a number of hardware sensors connecting to the deployment machine through RS232 serial ports.
But ... I'm developing on a machine without an physical RS232 serial ports, but I would like to make fake serial ports that I can connect to and output data from with the aim of faking input from hardware sensors.
Does anyone know of a way to create a fake serial port and control it on Windows XP?
If you are developing for Windows, the com0com project might be, what you are looking for.
It provides pairs of virtual COM ports that are linked via a nullmodem connetion. You can then use your favorite terminal application or whatever you like to send data to one COM port and recieve from the other one.
EDIT:
As Thomas pointed out the project lacks of a signed driver, which is especially problematic on certain Windows version (e.g. Windows 7 x64).
There are a couple of unofficial com0com versions around that do contain a signed driver. One recent verion (3.0.0.0) can be downloaded e.g. from here.
I know this is an old post, but in case someone else happens upon this question, one good option is Virtual Serial Port Emulator (VSPE) from Eterlogic
It provides an API for creating kernel mode virtual comport devices, i.e. connectors, mappers, splitters etc.
However, some of the advertised capabilities were really not capabilities at all.
EDIT
A much better choice, Eltima. This product is fully baked. Good developer tech support. The product did all it claimed to do. Product options include both desktop applications, as well as software development kits with APIs.
Neither of these products are open source, or free. However, as other posts here have pointed out, there are other options. Here is a list of various serial utilities:
com0com (current)
com0com - With Signed Driver (old version)
Yet another place for com0com with Signed Driver (Pete's Blog)
Tactical Software
Termite
COM Port Serial Emulator
Kermit (obsolete, but still downloadable)
HWVSP3
HHD Software (free edition)
I use com0com - With Signed Driver, on windows 7 x64 to emulate COM3 AND COM4 as a pair.
Then i use COM Dataport Emulator to recieve from COM4.
Then i open COM3 with the app im developping (c#) and send data to COM3.
The data sent thru COM3 is received by COM4 and shown by 'COM Dataport Emulator' who can also send back a response (not automated).
So with this 2 great programs i managed to emulate Serial RS-232 comunication.
Hope it helps.
Both programs are free!!!!!
There's always the hardware route. Purchase two USB to serial converters, and connect them via a NULL modem.
Pro tips:
1) Windows may assign new COM ports to the adapters after every device sleep or reboot.
2) The market leaders in chips for USB to serial are Prolific and FTDI. Both companies are battling knockoffs, and may be blocked in future official Windows drivers. The Linux drivers however work fine with the clones.
Another alternative, even though the OP did not ask for it:
There exist usb-to-serial adapters.
Depending on the type of adapter, you may also need a nullmodem cable, too.
They are extremely easy to use under linux, work under windows, too, if you have got working drivers installed.
That way you can work directly with the sensors, and you do not have to try and emulate data.
That way you are maybe even save from building an anemic system.
(Due to your emulated data inputs not covering all cases, leading you to a brittle system.)
Its often better to work with the real stuff.
i used eltima make virtual serial port for my modbus application debug work. it is really very good application at development stage to check serial port program without connecting hardware.

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