i can send multiline interface commands but not data commands

[tezamm]

hi
i am using a gpib controller.I cannot seem to find a way to switch between multiline commads and data commands.the key is the ATN bit as to send a DAB command the atn bit must be low. I cannot make the controller distinguish when a command is a adta command and not a multiline command,

[GPIB_Guru]

Please provide more information. Typically, provide the following information:
* What GPIB controller are you using?
* What programming language are you using?
* What operating system are you using?

Those are good starter questions. Typically the ATN line is asserted/unasserted automatically. If you make a call such as ibcmd to send command bytes, ATN will be asserted. If you make a chall such as ibrd, ATN will be unasserted. However, this is dependent on your driver and GPIB board. Those API calls are for NI-488.2 using an NI GPIB board. Other vendors may offer a different API to send commands and data bytes.

[tezamm]

sorry bit i did not know i could answer you directly.

i am using the measurement computing gpib controller cb7210.2 which is nearly ni compatabile.i am interfacing it with a microcontroller connected to the pc.Then i am trying to use a monitor program that is embedded in the microcontroller to perform remote access of instruments.i am using assembly. i have managed to communicate with the instrument.now the problem is that i cannot make the distinction between data commands and interface commands.for eg if i send 3Fh and atn happens to be 1 this is interpreted as UNL if atn is 0 then it is interpreted as data command.i need to be able to have control of the atn bit so that i can send either at will. so to problem is how to control the atn bit.

thanks
again

[GPIB_Guru]

I am not very familiar with the cb7210, but if it is programmed like a regular 7210, there should be an auxmr register. Within that register should be three patterns, 0x10 which is gts, and 0x10/0x11 which are tca and tcs.

gts = Go To Standby, drops attention
tca/tcs = Take Control (A)synchronously, asserts attention

I recommend reviewing the cb7210.2 manual to determine how it is supposed to be programmed.

[tezamm]

i found the nat7210.2 manual and it said exactly what you suggested and it makes sense.

the cb7210.2 manual is not available as far as i know and that is my difficulty.all that i am doing i have to define from the data sheet.

thanks a lot for your answer appreciate it a lot.

i will get back to you if i find out if it works or not.

[Methis Elddir]

On Wed, 10 Mar 2004 07:39:24 -0600, tezamm wrote:

> i found the nat7210.2 manual and it said exactly what you suggested and it
> makes sense.
>
> the cb7210.2 manual is not available as far as i know and that is my
> difficulty.all that i am doing i have to define from the data sheet.

The cb7210 manual is on the MC site. For some reason, they just don't
provide any links. This should have what you need.

http://www.measurementcomputing.com/cb7210/