CompactPCI Hot Swap Question

[clnorris]

I'm using NI-VISA for register-based communication with a CompactPCI card on Windows 2000 using LabVIEW. I understand that Win2k is not natively aware of the cPCI architecture. Can NI-VISA handle cPCI board insertions and extractions?

I found an old NI knowledgebase article that says hot swapping is not part of the cPCI or PXI standards which I feel is mistaken as my cPCI board has a hot swap controller.

I'd appreciate any info on anyone's experiences with hotswap.

Chris Norris
Carrier Access Corp
(303) 218-5826

[Adam_U]

Win2k does not support the cPCI bus natively. The cPCI bus is basically the PCI bus in a different form factor. There is native support in Win2k and any other OS that supports a PCI bus. Please point me to this misinformation so it can be corected.

Since cPCI is a PCI bus, devices on it cannot be removed while the power is on (i.e. hot-swapped). This is equivalent to removing a PCI board while your computer is on. Since the power rails at the back of the chassis remain powered, you could fry your card if you attempt to remove it from a powered chassis. If you were lucky and did not fry the board, it is unlikely that any computer monitoring that cPCI bus would take kindly to this behavior on the bus. What kind of controller do you have. Does it say in the specs that it is "hot swappable"?

Intrigued,
-Adam

[Adam_U]

CORRECTION

Win2k does support the cPCI bus natively

[Adam_U]

Chris,

Upon looking into this further, CPCI can optionally support hot-swap but you will need to ensure that your devices support it. What devices are you going to use in your system (PXI/cPCI)? You will need to ensure that they are hot-swappable. For more information visit: PICMG.org.

[clnorris]

These particular cPCI devices have the hardware support for hot-swap. I've seen some 3rd party products such as Go-HotSwap that add the software support in Windows, but I was curious whether NI-VISA could do anything at a low-level to accommodate hot swap events. When I hot plug USB devices, NI-VISA behaves just fine. I'm guessing VISA is depending on Windows for the low level stuff.

-CN

[JoshuaP]

Although it hasn't been tested on cPCI, NI-VISA does support surprise removal notifications, if the OS supports it. Basically, if the OS will notify the NI-VISA driver that there was a surprise removal notification for the hardware we will take the appropriate steps to uninstall the device as well as if the OS informs us of a device insertion. It should act the same as when you power on or shut down a PXI chassis that has a MXI 3 connection without powering down your computer.

I hope this helps out.

Joshua Prewitt
National Instruments

[clnorris]

Looks like Win2k needs an os extension to support cPCI boards that have the hot-swap function. I installed a Jungo hot-swap eval on my cPCI controller, and now Windows responds to the insertions and extractions. When I go into NI-MAX, it shows the correct card configuration.

I noticed that WinXP "embedded" has a cPCI component. Otherwise, hot-swap support in Windows for cPCI seems fairly sparse.