>Ok, that is an entirely different use case indeed. This is entirely up to
>the frontend to drive. Effectively it needs to start a new acquisition
>whenever the old one ends, optionally keeping the old one on screen or
>scrollable or something.
This will need to be carefully designed since we want to minimize data loose
between triggers. Right now I believe I could only implement this by using the
stop/start capture api functions (correct me if I am wrong). However, this will
setup up a bunch of stuff on the scope, which will increase the time between
arming the triggers. I am capable of just reading from the MSO19 constantly,
and get data whenever it triggers. So I think we might need to add a
hw_dev_acquisition_continue api function.
If you guys dont mind, I am going to handle this in the
hw_dev_acquisition_start function for now, since all the protocol decodes will
work with this. So if you specify more then 1024 samples, it will warn you that
the samples are generated with multiple triggers and will have gaps in them. I
need this functionality right now, and this is one of the reasons I want to use
sigrok with this scope.
>To make matters worse, SR_HWCAP_CAPTURE_RATIO is specified as a number from
>0-100, and SR_HWCAP_HORIZ_TRIGGERPOS as a number from 0.0-1.0.
>Oh, the humanity.
I did not know what the SR_HWCAP_CAPTURE_RATIO did. It looks like it might be
more suitable for this at this point, since 0 would mean capture everything
after the trigger, 50 would mean half and half, and 100 would mean capture
everything before the trigger. Ultimately it would be nice to just have one
method (SR_HWCAP_HORIZ_TRIGGERPOS has the most verbose name) and have the
ability to pass in radio/time/units.
Lior.
________________________________
From: Bert Vermeulen <[email protected]>
To: Lior Elazary <[email protected]>
Cc: Sigrok-devel <[email protected]>
Sent: Tuesday, January 8, 2013 2:45 AM
Subject: Re: [sigrok-devel] link-mso19 drivers
On 01/08/2013 07:23 AM, Lior Elazary wrote:
> Here is an example of what I mean. Let say you have a device that outputs
> different SPI data every 500ms to communicate with another device. So
> device A will output 0x01 <wait 500ms> 0x02 <wait 500ms> 0x03 etc... Now
> the mso19 does not have a sufficient buffer to get the whole set of data,
> but I could set up a trigger to get the first data, rearm the trigger and
> get the second data, etc... Therefore there will be a gap in the data
> were the trigger had to rearm, but I dont care about that time, as long
> as that time is sufficiently short between dead zones. So it would be
> nice if I can just collect all the data from this device and use a
> protocol decoder to see what is this data is without having to have a
> huge sample buffer. Is there another way to achieve this?
Ok, that is an entirely different use case indeed. This is entirely up to
the frontend to drive. Effectively it needs to start a new acquisition
whenever the old one ends, optionally keeping the old one on screen or
scrollable or something.
sigrok-cli doesn't have such a mode currently, but it should be pretty easy
to implement.
> Thanks, this helps. However, my question was more on how to pass the
> value to the horiz_triggerpos from the GUI. Since this scope has only
> 1024 samples buffer, I may want to get 50 samples before the trigger and
> then 974 samples after the trigger. For now you can specify
> horiz_triggerpos=50 in sigrok client, but how would I do that in the GUI?
> It would be nice if there was a vertical line you can drag.
I don't think pulseview supports this yet. Joel, care to comment?
Incidentally, horiz_triggerpos (SR_HWCAP_HORIZ_TRIGGERPOS) is intended for
use with analog (scope) data, for logic data SR_HWCAP_CAPTURE_RATIO is used.
I remember thinking at the time that the two are really the same thing --
how much data to capture before the trigger -- but was unsure if there was
perhaps some reason to keep them separate. If anyone has further insights in
this, please comment.
To make matters worse, SR_HWCAP_CAPTURE_RATIO is specified as a number from
0-100, and SR_HWCAP_HORIZ_TRIGGERPOS as a number from 0.0-1.0.
Oh, the humanity.
--
Bert Vermeulen [email protected] email/xmpp
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