TNT4882 How to Clear MAV Bit

[Artur Funk]

Hello everybody.

I use TNT4882 in generic mode without interrupts. In a main loop the µC checks the ADSR register of the TNT. If TNT gets addressed as listener then the µC setup the TNT for input data and starts to read the data from the fifo. How is it possible to manipulate the MAV bit to avoid the second read?

[ralfn]

Hello Artur,

the TNT4882 has a pretty good manual: https://www.ni.com/docs/en-US/bundle/tnt4882-programmer-reference/resource/370872a.pdf

I understand the first part of your question: The microcontroller is checking the ASDR (Address Status Register) of the TNT in a loop to see if it is addressed as listener (bit 2r is high). However, I don't understand the MAV bit part of it. According to Appendix C, this has to do with the Message Available bit, which indicates whether a message is available in the queue. I don't know what you mean by "manipulate the MAV bit to avoid the second read". What is the second read you are referring to? Page C-24 of the manual shows the MAV in the status byte register, but I afraid the bit can not be manipulated...

I hope chapter 4 - 6 of the Software Reference Manual for TNT4882 will provide you with an answer.

https://www.ni.com/docs/en-US/bundle/370874a/resource/370874a.pdf

With best regards,

Ralf N.

[ralfn]

Artur,

I saw that you asked an equal question in another thread.

To keep things simple please use only one thread for one topic.

This thread will continue here... 

https://forums.ni.com/t5/Instrument-Control-GPIB-Serial/TNT4882-ENOL-problem/m-p/930691?requireLogin...

Cheers,

Ralf N.