Experimental Physics and
Industrial Control System

"Mark Rivers" <[email protected]> · Fri, 19 Jan 2007 14:57:53 -0600

I believe asyn is doing the flush operation that Emmanuel suggested.

I suspect you are not getting out of order replies.  I think you are getting a timeout, but then stale data from some buffer is ending up in the apparent data you received with the timeout.

Mark

________________________________

From: Phillip Sorensen [mailto:[email protected]]
Sent: Fri 1/19/2007 2:51 PM
To: Emmanuel Mayssat
Cc: TechTalk EPICS
Subject: Re: Out of order replies from a serial device

Emmanuel Mayssat wrote:
> Before you send a command to your serial device, you should clear the
> serial buffers.
>
> So a read operation becomes:
>
> 1/ Read ( you will read nothing most of the time), this operation
> clears /flushs the serial buffers.
> 2/ send your serial commnad/inquiry
> 3/ read the serial port a second time to get your PV value
>
> Note that this is also assuming that you are using serial port locking,
> and that this feature is working correctly (i.e. only 1 write-read
> request at a time )
>

That sounds like it would work, but I am currently using the asyn
devGpib device support module framework with GPIBREAD commands.  The
framework handles the actual communications.

I can rewrite the device support to use GPIBCVTIO commands and write the
communication code myself, but I would prefer to use the devGpib code
for as much as possible.

Phil Sorensen
CHESS

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System