I recently ran a test comparing the SPI triggering and decoding speed of Keysight EDUX1002G (modded to DSOX1102G) and Siglent SDS1104X-E
The details of the test was posted in a different thread:
https://www.eevblog.com/forum/testgear/everyday-bench-scope-a-3-way-race-edux1002a-gds-1054b-sds1202x-e/msg2412507/#msg2412507
Summary of test: STM32 nucleo board running @ 180MHz. 45MHz SPI clock. The test outputs 50,000 full cycles of 8 frames from 1 byte to 8 bytes. When a button is pressed, it sends a frame with 1 byte with value 0x3F. Normally one of the 8 frames has byte value 0x37 in the same position.
Conclusion: Keysight was able to trigger 50,000 times per second when triggering on byte value 0x37. Siglent SDS1104X-E triggered 3,000 times. The difference is due to the fact that the Keysight is doing Serial triggering and decoding in the ASIC and the Siglent implemented it in software after the memory was sampled.
In initial tests, I used a GWInstek GDS1054B and Micsig TO1104 with similar results to the Siglent SDS1104X-E, all of them have serial triggering and decoding implemented in software.
....and I find it very strange how, even doing things in software, the Siglent is only able to do 3.000 captures.
As I told in previous message.
Even with normal edge trigger 4000 captures/second (aka 4kwfm/s)
(4 channels on, 50ns/div, display vectors, interpolation Sinc aka Sin(x)/x)
Even when it can maximum average 118kwfm/s with same 50ns/div and one channel on, what is most fast for wfm/s speed and other settings so that maximum can reach but more channels on and not speed optimal settings speed is very different. This is not alone serial trigger/decode thing.
(sequence acquisition is then totally different and there it is nearly 10 times faster than KS but this is totally other case.)
@TK,
Could you test with different SPI speeds to see when you get the 50,000 cycles in Siglent and the others?
BTW, I think the test you've done is extremely relevant and I find it very strange how, even doing things in software, the Siglent is only able to do 3.000 captures.
One thing is HW vs SW, the other is realtime vs post processing...
Hello,
Is it possible to share your System Workbench project ?
I have severals Nucleo F446 and it will be nice to test on my own scope : )
Thank you
@TK,
Could you test with different SPI speeds to see when you get the 50,000 cycles in Siglent and the others?
BTW, I think the test you've done is extremely relevant and I find it very strange how, even doing things in software, the Siglent is only able to do 3.000 captures.
One thing is HW vs SW, the other is realtime vs post processing...During the test I tried 1MHz and some other SPI speed and the result was similar, I will test later again but I doubt the SDS1104X-E will get any higher than 3,000 trigger updates per second.
@TK,
Could you test with different SPI speeds to see when you get the 50,000 cycles in Siglent and the others?
BTW, I think the test you've done is extremely relevant and I find it very strange how, even doing things in software, the Siglent is only able to do 3.000 captures.
One thing is HW vs SW, the other is realtime vs post processing...During the test I tried 1MHz and some other SPI speed and the result was similar, I will test later again but I doubt the SDS1104X-E will get any higher than 3,000 trigger updates per second.
Yes, very possible.
But still I ask, did you use dots or vectors display because it is just there around in borderline affecting or not affecting with this t/div (50ns/div in your image) and all or 3 channels on. (and then if also decode is on, it drops more due to longer blind time cap, once in every TFT refresh 40ms period. I do not mean between acquisitions blind time what is other but independent thing in scope processing)
Even without serial trig and/or decode maximum wfm/s speed is as told previously.
But as you can see maximum is different depending also display etc settings.
With serial trigger of course it can not be faster than with normal edge trigger or without signal auto free run.
So, with this 3000/s result. With dots or vectors mode? If vectors mode was it Sinc or x?
BTW, why all others stick at the 3.000 mark? Their characteristics are not so similar...
This is indeed very interesting/intriguing...
I'm trying to decide on what equipment to buy and now you've thrown this cold water bucket....
Another interesting capture. Keysight triggers correctly on 0x37 and decodes the SPI frame (0x37 0x45 0x45 0x56 0x42 0x4C 0x4F 0x4F = "7EEVBLOG"), even when the waveform is very distorted, almost beyond recognition due to having only 1Mpts sample memory. It was captured with timebase @ 1ms, acquisition: 50MSa/s
Trying to avoid a rep war here, sorry everyone! Regarding online/offline decoding, the Keysight InfiniiVision scopes decode whatever's on screen nearly instantaneously with the ASIC as discussed above. Even changing the time/div setting on a capture will cause the scope to re-decode the screen. This is part of the speed, it only processes what you can see & analyze and ignores what's off screen.
Another interesting capture. Keysight triggers correctly on 0x37 and decodes the SPI frame (0x37 0x45 0x45 0x56 0x42 0x4C 0x4F 0x4F = "7EEVBLOG"), even when the waveform is very distorted, almost beyond recognition due to having only 1Mpts sample memory. It was captured with timebase @ 1ms, acquisition: 50MSa/s
Can you open Siglent decode list when it is running (or both stop and running) (image where is 1ms/div) and tell how many messages it have totally decoded, as you can see in image left bottom there is decoded (MOSI) and light blue mostly tell, without errors. First over 1.5ms from beginning of acquisition.
It have many times told that Siglent have limits in decode result. I have not measured it using SPI but with UART and IIC (Wire), it is 1000 messages (tested with IIC 32bytes messages and 1 - 32bytes, max decode result length is messages is 1000)
Then open also KS decode list when it is running (or both, run and stop) (image where is 1ms/div) and tell how many messages it have really decoded in decode list. And what mean this bottom decode display (S1) color change and gap around 1ms from left. And why it show 350kHz.
Also, these other two images, you set KS for 500ns/div
then you set Sig 200ns/div
Can you open Siglent decode list when it is running (or both stop and running) (image where is 1ms/div) and tell how many messages it have totally decoded, as you can see in image left bottom there is decoded (MOSI) and light blue mostly tell, without errors. First over 1.5ms from beginning of acquisition.
It have many times told that Siglent have limits in decode result. I have not measured it using SPI but with UART and IIC (Wire), it is 1000 messages (tested with IIC 32bytes messages and 1 - 32bytes, max decode result length is messages is 1000)3000Then open also KS decode list when it is running (or both, run and stop) (image where is 1ms/div) and tell how many messages it have really decoded in decode list. And what mean this bottom decode display (S1) color change and gap around 1ms from left. And why it show 350kHz.KS 1000X does not have decode list. I think it shows 350KHz because it is trying to measure on CH1 that has a distorted waveform and it is not counting the actual 45MHz SPI clock signalAlso, these other two images, you set KS for 500ns/div
then you set Sig 200ns/divJust trying to show that after some packets (which happens to be 3000), SDS1104X-E stops decoding.
Can you open Siglent decode list when it is running (or both stop and running) (image where is 1ms/div) and tell how many messages it have totally decoded, as you can see in image left bottom there is decoded (MOSI) and light blue mostly tell, without errors. First over 1.5ms from beginning of acquisition.
It have many times told that Siglent have limits in decode result. I have not measured it using SPI but with UART and IIC (Wire), it is 1000 messages (tested with IIC 32bytes messages and 1 - 32bytes, max decode result length is messages is 1000)3000Then open also KS decode list when it is running (or both, run and stop) (image where is 1ms/div) and tell how many messages it have really decoded in decode list. And what mean this bottom decode display (S1) color change and gap around 1ms from left. And why it show 350kHz.KS 1000X does not have decode list. I think it shows 350KHz because it is trying to measure on CH1 that has a distorted waveform and it is not counting the actual 45MHz SPI clock signalAlso, these other two images, you set KS for 500ns/div
then you set Sig 200ns/divJust trying to show that after some packets (which happens to be 3000), SDS1104X-E stops decoding.
You can show it better if you zoom to this position where is last decoded message and start undecoded part
Now it looks weird (specially alone this 200ns image because there was not any decoded packet and it looks like .. oh Siglent can not decode at all but then you show KS what have decoded. Nearly like some biased intrument owner except that I do not believe this is case at all.
But how you get decode result out from this image where KS t/div is 1ms.
Also you did not answer this question about KS bottom image decode display question. How many messages it decode in this image?
If there is not decode list with time position and data how you look decoding result at all with this setting. I mean, what is purpose of Decode if result is unavailable.
If it is unavailable (difficult to believe that it can decode but can not show result - it do not feel weird if it is some unknown junk but front panel label read Keysight (aka raped Hewlett-Packard) or if it need more exercise how to use these very different machines for get out decode result. As we also know different vehicles driving need different handling.
Ok. So with SPI it have limit 3000, more than with IIC what have limit 1000. (32000 bytes)