Re: [Linux-gpib-general] [EXTERNAL] Re: GPIB as a pure slave

[Stefan O. <ste...@jh...>]

Hi Dave,

I have the same results with slave_test2 :

root@imx8mm-var-dart:/home/stefan/bin# ./slave_test2
[  135.918117] tnt4882: minor 0 read timed out
[  135.922325] tnt4882: read timed out
Got *IDN?

[  138.990013] tnt4882: write timed out
error: ibwrt fail
  - EABO 6: Operation aborted
root@imx8mm-var-dart:/home/stefan/bin#


I am using computer with Win10 and National Instruments GPIB packages -> 
NI-VISA interactive control program for GPIB. As a commands I am using 
"query", send the request and waiting for the answer. This Win10 
computer is connected to HW (Variscite board with NI PCIe-GPIB (rev 02)) 
with Yocto linux 5.10 image via NI GPIB-USB-HS+ connector.

I am handling scenarios as follows:

No TACS or LACS is set => use poll timer to check if It is any change - 
1second.

LACS is set => use poll timer 200ms to check if read ( ibrd ) returns 
any data. If yes, read till end-of-the data and save them. Set flag to 
answer. When CIC do not address slave as a TACS ( use e.g. only write 
command ) I am getting, of course, read time out. But this is  OK, no 
data on the GPIB bus.

TACS is set => try send the data back to the master - CIC. Clear flag to 
send data.

I am not getting any notifier from the kernel to activate communication. 
Therefore I am using polling mechanism. It is OK for me now.

As I have mentioned already. Reading seems to me OK. When data are on 
the GPIB bus, I am reading them. When no data, I am getting read time 
out. But I have somehow to check, if any data are ready to be read => 
poll mechanism.

Write seems to me bigger problem, as I have already described.

Stefan


On 1/16/23 14:01, dave penkler wrote:
>
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>
> Hi Stefan,
> It looks like in your case the slave board was already addressed as a 
> listener before you started slave_test which is why you got the timeout.
> Here is a new version that deals with this case. It loops until it 
> reads a string when addressed as a listener and then writes back that 
> string when addressed as talker. If the read times out it prints "read 
> timeout" and goes back to the loop.
> On the master side once a string has been written the response must be 
> read before writing another. Are you using ibterm on the master or 
> something else ?
>
> $ ./slave_test2
> read timeout
> read timeout
> Got hello
> Got bye
> Got quit
> slave done
> $
>
> cheers,
> -Dave
>
> On Sun, 15 Jan 2023 at 09:46, Stefan Olejnik 
> <ste...@jh...> wrote:
>
>      Hi, Dave
>
>     Thanks a lot for Your effort.
>
>     I have tested Your program, but it is almost the same as I have
>     used. The result are as follows:
>
>     root@imx8mm-var-dart:/home/stefan/bin#
>     root@imx8mm-var-dart:/home/stefan/bin# ./slave_test
>     [  124.896503] tnt4882: minor 0 read timed out
>     [  124.900712] tnt4882: read timed out
>     Got hello
>     [  127.968496] tnt4882: write timed out
>     error: ibwrt fail
>      - EABO 6: Operation aborted
>     root@imx8mm-var-dart:/home/stefan/bin# ./slave_test
>     [  187.105354] tnt4882: minor 0 read timed out
>     [  187.109563] tnt4882: read timed out
>     Got *IDN?
>
>     [  190.177371] tnt4882: write timed out
>     error: ibwrt fail
>      - EABO 6: Operation aborted
>     root@imx8mm-var-dart:/home/stefan/bin#
>
>     READING:
>
>     Interesting is that during "ibrd" even read timeout is coming from
>     TNT4882, the data are read OK. I am using reading per char,  till
>     END or END-OF-STRING => "\n"  and I am getting no time-out during
>     reading.
>
>     WRITTING:
>
>     First "ibwrt" is always time-outed, the second also, but data are
>     delivered, as I am already described. Therefore I am using short
>     TIMO ( e.g. 10ms ) for ibwrt, and on the receiver device is TIMO
>     set to 3s, and I am getting the data. Of course from second "ibwrt".
>
>     Stefan.
>
>
>
>
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