Experimental Physics and
Industrial Control System

marco_hair <[email protected]> · Wed, 1 Oct 2008 00:14:27 +0800 (CST)

å2008-09-30ï"Eric Norum" <[email protected]> åéï
>On Sep 30, 2008, at 7:58 AM, Silver wrote:
>
>> hi, all:
>>
>>  I want to write a driver for one of our serial devices, so I read  
>> "How to create EPICS device support for a simple serial or GPIB  
>> device". (http://www.aps.anl.gov/epics/modules/soft/asyn/R4-9/HowToDoSerial/tutorial.html 
>> )
>>
>> While I have several questions:
>>  1. in the tutorial, it said:
>>
>> Command array index 0 â Device Reset
>> {&DSET_LO, GPIBWRITE, IB_Q_LOW, NULL, "\377\377\033", 10, 10,
>>       NULL, 0, 0, NULL, NULL, "\033"},
>> I don't understand what's the meaning of "\377\377\033", does it  
>> mean "377" is oct number?
>
>Yes.  That's standard C syntax.
>If you prefer hexadecimal the equivalent would be "\xFF\xFF\x1B".
>
>>
>>
>>  2. in function "convertPositionReply" and "convertStatusReply",
>> first time, pli->val = pdpvt->msg[0];
>> second time, pli->val = pdpvt->msg[1];
>> Does it mean the AB300's response data begin from different  
>> position? can anyone give me some explanation?
>
>The AB300 response always contains both position information (in the  
>first character) and status information (in the second character).
>
>>
>> I have never used GPIB device before, so forgive my innocence.
>> Thanks a lot in advance.
>
>If your device is IEEE-488.2 compliant the makeSupport .pl command in  
>the ASYN distribution will set up a number of command table entries  
>that you could study.  The command usage is:
>/bin//makeSupport.pl -t  
>devGpib 
>
>-- 
>Eric Norum

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System