Products > Test Equipment
Siglent SDS2000X Plus - Bugs / Missing Features / Feature Requests
Slartibartfast:
--- Quote from: tautech on December 03, 2023, 10:17:05 pm ---
--- Quote from: ebastler on December 03, 2023, 10:03:00 pm ---But acquisition is stopped. The data signal is right there with all the bits, and a clean-looking clock too. Why can't it be decoded? I also fail to see how triggering could get in the way.
--- End quote ---
If it need be Stop'ed, Trigger or some other decode setting are not optimal.
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Sorry, but this is bullshit. There are always cases where picking a specific instant in time (and none later) in a complex, non-repetitive signal is just not within the trigger capabilities of any given scope. This is particularly frequent on digital buses. You want to see that instant, and avoid having the scope re-triggering on later events, you choose single acquisition. That's what it's for. And after it triggered, it stops.
Slartibartfast:
--- Quote from: ebastler on December 03, 2023, 10:29:29 pm ---We don't know if it had to be stopped to decode at all, or was just stopped to take the screenshot.
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In this case, I'm debugging firmware. I wanted to see the very first few transactions on the bus because those are the only ones where I know precisely what data is supposed to be transferred. So I set the scope to single trigger, and reset the MCU.
ebastler:
--- Quote from: tautech on December 04, 2023, 08:57:03 am ---Sure for single it shouldn't be needed however in Run mode the correct Holdoff gives rock solid triggering although with multiple packets coming through the payload is often changing.
I need make room on the bench to setup some examples......
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I don't think examples will be needed. Nobody is doubting that a holdoff time can be useful when triggering on complex recurring sequences. All we are saying is that holdoff is a solution which has nothing to do with slartibartfast's present problem. :-//
Slartibartfast:
I had a hunch, and it looks as if it was right.
In the wild, perfect signals are the exception, usually signals are messy in one or the other way. Here, the borderline pull-ups. I added additional pull-up resistors (i.e. in parallel) up to the point where the resistance becomes so low that the EEPROM is getting close to the limit of it's driving capability. The signals are cleaner in the sense of rising much more rapidly. And lo and behold! The decoder works a lot better!
The first screenshot shows the previously shown first read transaction on the bus. Now the decoder keeps sync perfectly and decodes properly. The same is true in the second picture where it has to work with less samples per bit. On a side note: Here is in fact a bug in the firmware of the device I'm working on: It writes 15 bytes in a row, which these standard EEPROMs cannot handle this way.
So it seems to me that it is not a bug in the I2C decoder per se what I have observed, but a really lousy capability of dealing with less-than-perfect signals. This really could do with an improvement, as my original signals were still clean enough for the chips involved, so test equipment should also be up to the task.
Apart from that, a few minor observations and wishes on the scope:
* After one of the last upgrades (don't know which) it seems the option of choosing the storage path seems to have disappeared, I cannot find it anymore. Where is it? It is not where the manual says it is.
* I like the option to not include the menu bar in the screenshot, but can we get rid of the mouse pointer as well? That would be really good for using shots in documentation, where they should be clean. A menu bar is easy to edit out, a mouse pointer, possibly covering a bit of a trace, not so.
* After hitting the PRINT button, a box appears saying "Saved to file ... / Next save as file ...". Is there a way to make that box disappear automatically?
* I believe it normally is not necessary to specifically unmount a USB drive before disconnecting it. At least, neither Linux nor Windows complains about an inconsistent file system, and I also found no hint of any such requirement in the manual. In addition, I cannot find in any menu any button that would trigger an unmount. However, I observed a few times, that after pulling out a USB stick, even after allowing several extra seconds to complete the write, the scope would not accept any USB sticks anymore.Beyond these, I'm still very happy with the scope.
Cheers Peter
Martin72:
--- Quote ---After hitting the PRINT button, a box appears saying "Saved to file ... / Next save as file ...". Is there a way to make that box disappear automatically?
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Should come with the next update - On my HD this has been already "fixed".
Edit:
https://www.eevblog.com/forum/testgear/siglent-sds2000x-hd-missing-features-and-bugs/msg5114079/#msg5114079
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