9914 timeout

[sma]

I am developing a GPIB interface using the 9914 ASIC.  Following a timeout as a result of a talker or listener failure what needs to be done to reset/reconfigure the device so that it is ready for the next activity.

The 9914 seems to lock up in both Controller and Talker/Listener modes.

Reapplying the intialization sequence works however this seems extreme.

[Steven_T]

Hello swa,

When these timeouts happen, is the Err bit in ISR1 set?  According to the manual a software reset is necessary to clear the bit if the SISB bit is not set.  Otherwise reading the ISR1 should be enough to clear it. 

What is going wrong with the communications?  A little more information could be very helpful.

Steven T.

[sma]

As described in my previous message regarding the missing first character, my electronics receives the talk command and passes this on to a second controller.  If the second controller times out due to an instrument error or similar the input channel will also time out.  When this occurs the input channel needs to be released.  The error bit for the input controller will not be set.

It appears that I will need to reset this device.

Message Edited by sma on 06-05-2007 04:35 AM

[Steven_T]

Hello sma,

I guess I'm unclear about why the first controller would be timing out because of the second one.  When the second controller gets the error, is the first one waiting for data from the second controller?  Is it getting ready for an operation but never completing it?

Thanks for any more information you can provide.

Steven T.

[sma]

You understanding of the problem is correct.

The input channel recieves the talk cmd from the ATE's gpib controller.  This talk command is transferred to the output channel of my interface to the instruments attached.  Hence the input channel has a timing loop which matches the timeout of the ATE's gpib interface.  So the input channel is waiting to receive the data from the attached instruments via the ouput channel.

The output channel also has a timeout loop which if expires due to instrument failure or similar terminates the listening function of the output channel.  At this point the program returns from the output handler and at this point I consider that the input channel has timed out.  Because it does not complete the required transfer of data back to the ATE's controller it is stuck in that function waiting for data.

Hope this helps.