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<== Date ==> <== Thread ==>

Subject: Re: USB interface with EPICS
From: Eric Norum <[email protected]>
To: Till Straumann <[email protected]>
Cc: "Chestnut, Ronald P." <[email protected]>, "Kevin M. Peterson" <[email protected]>, tech-talk <[email protected]>
Date: Mon, 18 Dec 2006 16:20:52 -0600
True, devices on the USB can not make unsolicited requests for service. But that's not a show-stopper. Consider all the GPIB devices in use which do not use the SRQ line -- the situation in that case is quite similar.

USB controller chips do have interrupts so it's not necessary for a device driver to continuously poll some register in the controller to see when a message has arrived.

On Dec 18, 2006, at 4:06 PM, Till Straumann wrote:

Just a side note before becoming excited about USB:
AFAIK (but I could be wrong), USB has no real interrupts
but always works in some sort of 'polled' mode. There could
be latency issues with USB devices if you need really fast response.

-- Till

Chestnut, Ronald P. wrote:
Kevin,

At SLAC, one of the RF physicists started using USB. To keep matters simple, he developed subroutines with which he could write to and read from USB. We then hook these in with subroutine records when time comes to put EPICS on it.

I'd also like to see some real USB driver-supported stuff.

Ron Chestnut
-----Original Message-----
From: Kevin M. Peterson [mailto:[email protected]] Sent: Monday, December 18, 2006 7:44 AM
To: tech-talk
Subject: USB interface with EPICS



Is anyone using the USB interface with EPICS? Of particular interest is the ThorLabs APT series.


Thanks,

Kevin Peterson
[email protected]




-- Eric Norum <[email protected]> Advanced Photon Source Argonne National Laboratory (630) 252-4793



Replies:
Re: USB interface with EPICS Till Straumann
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RE: USB interface with EPICS Chestnut, Ronald P.
Re: USB interface with EPICS Till Straumann

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