End or Identify (EOI) character ?

[Adriaan Renting]

You might be able to find more about GPIB under the names IEEE488 and HP-IB.
It's a 8-bit parallel communications bus used in lab-automation. But it's been like 10 years since I used it so I don't remember the specifics. I once wrote a driver for it under windows 3.0.
Most of the communication is indeed human readable ASCII, but there are some extra lines used. On googling I found: 
 "The five interface management lines (ATN, EOI, IFC, REN, SRQ) manage the flow of control and data bytes across the interface" 
in this document:
http://www.techsoft.de/htbasic/tutgpibm.htm?tutgpib.htm

This means that EOI isn't an ASCII character, because it's not transmitted on any of the data lines. You'll probably need to access some specific adress in the GPIB controller, or use it's driver, to get/set the state of the management and the handshake lines.
 
>>>Donn Cave <donn at u.washington.edu> 09/19/05 6:33 pm >>> 
In article <mailman.552.1127021597.509.python-list at python.org>, 
"Terry Reedy" <tjreedy at udel.edu> wrote: 
 
>"Madhusudan Singh" <spammers-go-here at spam.invalid> wrote in message 
>news:432cb8fd$0$18650$14726298 at news.sunsite.dk... 
>>Hi 
>> 
>>I was wondering how does one detect the above character. It is returned 
>>by 
>>an instrument I am controlling via GPIB. 
> 
>EOI = chr(n) # where n is ASCII number of the character. 
># then whenever later 
>if gpid_in == EOI: #do whatever 
 
Which begs the question, what is the ASCII number of the 
character?  I was curious enough to feed GPIB and EOI into 
a search engine, and from what I got back, I believe it is 
not a character, but rather a hardware line that may be 
asserted or not.  GPIB, whatever that is, may support some 
configuration options where EOI causes a character output, 
but the actual value depends on configuration.  The documentation 
is probably the place to find out more about this stuff. 
 
  Donn Cave, donn at u.washington.edu 
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