Hello Michael,
first of all, SIGMA uses USB 1.1 with transfer rate 12Mbit, actual
transfer rate is about 400kB/s. The internal memory is 256Mbit or 32MB.
Therefore it takes about up to one minute to download the data from the
analyzer, depending on actual memory usage.
SIGMA can acquire incredible amount of samples. Typically it can store
2M samples with up to 64k RLE timestamp. In most cases, like SPI
communications it can simply store 2M clock edges, or 1M clocks. When
you combine this with expected clock rate and sample rate 50Msps, you
have hundreds mega samples, which is incredible amount of memory.
Actually, maximum number of samples is 2^37, more than int32 limit.
The original SIGMA software uses both in-memory compression and also
downloads as a matter of priority data, where is user zoomed in. This is
reason why it takes only one or two seconds.
Best regards,
Ondřej
On 2.8.2017 8:05, Gerhard Sittig wrote:
On Mon, Jul 31, 2017 at 09:43 +0200, KAPLAN Michael / EVVA Wien wrote:
Hi!
I just tested your changes, and it works like a charm now :-)
Thank you for testing!
I tried at several sampling rates (up to 50MHz) - everything ok
- except that there is no UI feedback when fetching large data
from the device (setting 500MSamples at 50MHz and pressing stop
around 5 seconds ... UI freezes for some seconds) but I guess
this is a pulseview related thing.
It appears to be the result of the specific combination of a
non-streaming device with slow(?) sample data downloads and/or
huge amounts of sample data to retrieve, which results in an
extended period of time between pressing the button and starting
to draw traces, where the user cannot perceive progress or
feedback from the UI. IOW it may be non-trivial to reproduce.
Have filed https://sigrok.org/bugzilla/show_bug.cgi?id=1003 for
this issue. Can you please check and maybe add information in
case I missed something?
virtually yours
Gerhard Sittig
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