USB devices listed under Device Manager

[jom]

Hello all

I'm very much a novice when it comes to ports on a PC.  I've struggled with this in the past so I thought I'd use an example to try to alleviate some issues I've had with this subject.

What I have are two devices that are connected up to my Windows 7 PC through USB ports.  Device #1 is actually an RF Synthesizer that has some sort of ATMEL microcontroller device on the other end.  I do not know what type of embedded software is being used.  What I do know is that it shows up under "Ports" in the Device Manager of my PC and is listed as "COM2" or "COM6" or whatever.  I believe this to be a USB device set up as a "virtual COM port".  If I'm incorrect in this please let me know.

The other device is an Evaluation board for a CP2130 chip from Silicon Labs.  This device takes USB data and turns it into SPI for various uses.  This device however shows up under "Silicon Labs SUB Devices" in the Device Manager in Windows and NOT under "Ports" like the other device.

So my question:  Is this 2nd device (from SLABS) being set up as a virtual COM port as well?  If not, what is it exactly?

I suppose this question is rather simple for most here but I find much of the USB material rather abstract at times.  This question will help me understand and eventually help write some VB.net code for the SLAB SPI chip interface.

Thanks for your patience.

jom

[Jan Axelson]

You're correct on the first device.

The second device might be using a vendor-provided driver.

To find out what driver a device is using, in Device Manager, click Driver > Driver Details.

The driver defines how you access the device. If it's a vendor-provided driver, you likely will use a vendor-defined API.

[jom]

You're correct on the first device.

The second device might be using a vendor-provided driver.

To find out what driver a device is using, in Device Manager, click Driver > Driver Details.

The driver defines how you access the device. If it's a vendor-provided driver, you likely will use a vendor-defined API.

I appreciate the response!

However, I'm pretty sure I don't know what an API is exactly.  I know it means App Programming Interface but I'm not sure what it is exactly.  I'm guessing it's NOT just some Windows app you use to run, say, my RF Synthesizer.  If that were the case both of these devices do have such software but it doesn't explain why they show up differently in the Device Manager.

However, more to the heart of my issue.  In the past, I've been able to connect up to  "virtual COM" port devices (such as this RF Synth) using VB.net.  Your book in fact goes over this quite well (thanks for that!).  However, I'm not sure I know how to connect up to this other device that does NOT show up as a COM port.  Would you do it the same way somehow?  The reason I've asked is that I've tried to detect this device using a standard COM port Windows app and it will NOT show up.  So there is something different about it that I don't understand.  An answer to this would lead me to find out how I can build my own app that CAN detect this device.

Thanks for any info that can shed some light on this for me.

jom

EDIT: I forgot to ask about the drivers.  If the 2nd device is using some sort of Vendor-provided driver can I assume then the driver used by the 1st device is a standard Windows driver such as usbsys or something like that?  I'm only guessing here....

[Jan Axelson]

Device Manager will tell you what driver the device is using.

If it's a vendor-provided driver, you will need documentation from the vendor that tells you what API (functions, etc.) to use to access the device.

If it's the Windows-provided COM-port driver, you can use .NET's SerialPort class. If it's the mass-storage driver, you can use file system functions. And so on.

[jom]

Thanks

It turns out under "Driver Details" three files are listed for this 2nd device.

winusb.sys and two .dll files.  So can I assume this is NOT being set up as a COM port?

Thanks again.

jom

[Jan Axelson]

No, it uses the WinUSB driver:

http://janaxelson.com/winusb.htm

But you will likely need documentation from Silicon Labs to find out how they are using the driver. For example, they may use vendor-defined commands.

[jom]

OK, it makes a bit more sense now.

To summarize: The 1st device used something like usbser.sys or some such.  The 2nd device used winusb.sys.  So the first one seems to be a COM port type driver while the second one is not.

Also, thanks for the link to the software.  The software is a bit over my head at the moment but I'll have to sift through it if I'm to get anywhere.  I'm also going through the SLABS files as well.

Thanks again!

jom