AnsweredAssumed Answered

vrf usb PIC interface (solution)

Question asked by b.birmingham on Apr 24, 2005
Thanks to all those who responded to my original question.
The answer (for anyone else who might need it) is actually very easy.

The PIC devices with built in USB are recognised by Windows as HID devices if
you download and the use the Microchip software examples.

To access them from VEE all you need is to download a file called This was difficult to find but a search on the name (once you
know what it is!) locates it. This contains allsorts - but includes an ActiveX
control (VBHIDComm.ocx ) with Read/Write commands etc so VEE can
communicate directly with a buffer inside the PIC.

------- Previous messages follow -------
Subject:             RE: [vrf] usb PIC interface
Date sent:           Thu, 24 Mar 2005 15:38:11 -0700
From:                "BAYES,SCOTT (A-Loveland,ex1)" <>
To:                  VRF <>
Send reply to:       "BAYES,SCOTT (A-Loveland,ex1)" <>

Hi Detlef and vrf,

To expand on Detlef's explanation, VISA USB support is only available
for USB Instruments, not for random USB devices (i.e. not for
scanners, digital cameras, printers, random designs, etc).

What defines a "USB Instrument" for this purpose?

Check out the support matrices at
<>. You can find the spec that
the instrument is required to meet at the bottom of the following

Matrix of Agilent IO Libraries interfaces
Matrix of Agilent IO Libraries revisions 

You'll see that the device must meet the USBTMC or USBTMC-USB488 specs
for VISA to talk to it.

If it doesn't meet one of these specs, than as Detlef mentions you'll
need a dll or maybe an ActiveX or .NET object to talk to it from VEE.

The main exceptions to this that I know of are USB-Serial converters,
the drivers for which make them look like serial ports and hide their
USB-ness. Other VISA-compatible converters, such as the 82357A
USB-GPIB, implement one of these specs, as far as I know, as do
direct-connect USB instruments such as the 33220A.

Best Regards,

Scott Bayes
Software Technical Support

Agilent Technologies, Inc.
815 14th Street S.W.
Loveland, CO, U.S.A. 80537

970 679 3799 Tel
970 635 6867 Fax

> -----Original Message-----
> From: Baranski, Detlef []
> Sent: Thursday, March 24, 2005 5:06 AM
> To: VRF
> Subject: AW: [vrf] usb PIC interface
> Barrie,
> the io-Instrument manager and the Vee built in USB
> functionallity belongs to
> VISA lib and USB-GPIO Card only.
> If you have a different device with no VISA support, you have
> to use the
> library (.dll) or selfwritten program to access it....
> INstrument manager did not help in that case!
> best regards,
> detlef
> -----Ursprngliche Nachricht-----
> Von: barrie birmingham []
> Gesendet: Donnerstag, 24. Mrz 2005 12:09
> An: VRF
> Betreff: [vrf] usb PIC interface
> Some help please with a first attempt at using the USB interface. I
> have a prototype device based on a PIC with built in USB port
> connected to a PC running XP pro and Vee7. When connecting the USB
> cable, windows recognises the device and it appears in device
> manager as a HID device. (is this right?) What's the next step to
> get Vee to access it? The 'Edit USB0' in 'I/O config' shows no
> devices, and in 'instrument manager' 'add instrument' the USB
> address fields are blank/greyed out.
> Barrie Birmingham
Barrie Birmingham

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