EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: ebclr on June 06, 2017, 11:21:19 pm
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I'm playing with ESP32 SPI mode with this program
#define CSPIN 5
#include <SPI.h>
unsigned char Icount = 0 ;
void setup() {
pinMode( CSPIN, OUTPUT);
SPI.begin(18, 19, 23, 5); // sck, miso, mosi, ss (ss can be any GPIO)
SPI.setFrequency( 10000000 );
}
void loop() {
delay(10);
digitalWrite( CSPIN, HIGH);
SPI.transfer(Icount);
digitalWrite( CSPIN, LOW);
Icount++;
}
This program was set to SPI Clock for 30Mhzm 10Mhz, 5Mhz and 1 Mhz
Then I put my Rigol DS1054Z to check the signal expecting to see a crap unuseful picture, But for my surprise, the pictures are very nice and readable, I would love to see other scopes on the same price range showing the same waveform
(https://electronicmaker.files.wordpress.com/2017/03/ds1z_quickprint4.png) </Br>(https://electronicmaker.files.wordpress.com/2017/03/ds1z_quickprint3.png)</Br>
(https://electronicmaker.files.wordpress.com/2017/03/ds1z_quickprint2.png)</Br>
(https://electronicmaker.files.wordpress.com/2017/03/ds1z_quickprint1.png)</Br>
This Rigols instrument is a beast,
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I agree with you, though I don't know why you expected a "crap unuseful picture". The 3db bandwidth of the scope is well known to be in the 130MHz+ range, so a 30 MHz signal should be no problemo!
Cheers!
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I have a spare Raspberry PI and was looking for a Python script that simulates a demo board for test signals on a scope. I looked and did not find any. I was actually surprised that there were none.
I could write a nice little Python program to simulate a Rigol test board,. I was just being lazy and thought I would grab one off the internet. Was not so easy.
I also enjoy my Rigol scope.
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http://www.tek.com/lab-course/learning-oscilloscope-operation-using-raspberry-pi (http://www.tek.com/lab-course/learning-oscilloscope-operation-using-raspberry-pi)
Not what you mean?
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i don't get it, what did you expect? If anything you showed that you can probe correctly
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Pulses are well known for the huge amount of harmonics they generate, and a 10 Mhz pulse train on a 50 Mhz scope, show with that nice shape ( ok is a little slow rise time ) but is totally valid for a test or even decode by eyes.
If I put this same signal on my 100Mhz Owon SDS2702 will be much worse than that I can't even trigger the signal.
Basically, I'm happy with my 399 USD scope, I don't need to expand 1500 USD or more, do work with microprocessor interfaces even pushing SPI to 10 Mhz.
But I still desire a Tek MSO/DPO4000B but have no extra cash to expand, for my purpose is a luxury but maybe sometime I will do an emotional order
Will be a nice thing to see the same signal on other scopes, even the big boy's ones,
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If I put this same signal on my 100Mhz Owon SDS2702 will be much worse than that I can't even trigger the signal.
pics? i find that hard to believe
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Yep, the (hacked) DS1054Z is an awful lot of 'scope for $400.
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If I put this same signal on my 100Mhz Owon SDS2702 will be much worse than that I can't even trigger the signal.
pics? i find that hard to believe
A bit of Holdoff and a falling edge trigger and it will trigger better than in the screenshots in the OP.
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If I put this same signal on my 100Mhz Owon SDS2702 will be much worse than that I can't even trigger the signal.
pics? i find that hard to believe
A bit of Holdoff and a falling edge trigger and it will trigger better than in the screenshots in the OP.
Even just Single Shot would have helped. A little decoding would have been nice.
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Thanks. Reading it now.
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Pulses are well known for the huge amount of harmonics they generate, and a 10 Mhz pulse train on a 50 Mhz scope, show with that nice shape ( ok is a little slow rise time ) but is totally valid for a test or even decode by eyes.
If I put this same signal on my 100Mhz Owon SDS2702 will be much worse than that I can't even trigger the signal.
Sounds more like operator error than a problem in the oscilloscope >:D
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"Even just Single Shot would have helped"
The SPI contour is running, and you can watch dynamically the bit's changing on screen, this will never happen on single shot
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This program was set to SPI Clock for 30Mhzm 10Mhz, 5Mhz and 1 Mhz
The last screenshot looks like it's still at 10MHz, I'm curious about the actual behaviour at 30MHz.
I might try when I'm back home.
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Here the image you asked for
Software runs on this hardware with USB power
(https://cdn.sparkfun.com//assets/parts/1/1/5/6/4/13907-01.jpg)
(https://electronicmaker.files.wordpress.com/2017/03/ds1z_quickprint10.png?w=680)
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As your voltage is going below ground, your suffering from lead inductance, try the spring ground tip for that last one, i expect some resonably sharp edges
Personally i am a little biased in wanting to see how well it can go as a current project of mine will likely need to probe 48MHz spi, possibly up to 84MHz and things in that frequency ballpark. (Dont yet have a dso)
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Still on regular probe but with a more decent ground path. I lost my spring ground somewhere
(https://electronicmaker.files.wordpress.com/2017/03/ds1z_quickprint12.png)
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Waiting for my ESP32 Thing card to test on my EDUX1002G (modded to DSOX), micsig TO1104 and Agilent 54622D
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MICSIG TO1104 100MHz 1GSa/s 4-channel Tablet scope. I added one extra test with SPI @ 40MHz
(https://www.eevblog.com/forum/testgear/rigol-ds1054-is-a-champion/?action=dlattach;attach=324516;image)
(https://www.eevblog.com/forum/testgear/rigol-ds1054-is-a-champion/?action=dlattach;attach=324518;image)
(https://www.eevblog.com/forum/testgear/rigol-ds1054-is-a-champion/?action=dlattach;attach=324520;image)
(https://www.eevblog.com/forum/testgear/rigol-ds1054-is-a-champion/?action=dlattach;attach=324522;image)
(https://www.eevblog.com/forum/testgear/rigol-ds1054-is-a-champion/?action=dlattach;attach=324524;image)
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Keysight EDUX1002G modded to DSOX1102G. 2GSa/s 100MHz 2+1 channel. Using extra digital channel to trigger on SCK (SPI clock).
(https://www.eevblog.com/forum/testgear/rigol-ds1054-is-a-champion/?action=dlattach;attach=324532;image)
(https://www.eevblog.com/forum/testgear/rigol-ds1054-is-a-champion/?action=dlattach;attach=324534;image)
(https://www.eevblog.com/forum/testgear/rigol-ds1054-is-a-champion/?action=dlattach;attach=324536;image)
(https://www.eevblog.com/forum/testgear/rigol-ds1054-is-a-champion/?action=dlattach;attach=324538;image)
(https://www.eevblog.com/forum/testgear/rigol-ds1054-is-a-champion/?action=dlattach;attach=324540;image)
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Keysight EDUX1002G modded to DSOX1102G. 2GSa/s 100MHz 2+1 channel. Using extra digital channel to trigger on SCK (SPI clock).
It would it nice to see the clock on an analog channel as well? :popcorn:
What's on channel 1? Is that just crosstalk?
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I'm guessing all the ringing is just from the probing method used? I'd be a little concerned seeing 0.5V of noise on a 3.3V signal.
Still glad to see that even with a high sampling rate, analog bandwidth will still bite me in the backside.
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I'm guessing all the ringing is just from the probing method used?
Yep. Don't try to infer anything from the ringing when you're using ordinary probes.
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Keysight EDUX1002G modded to DSOX1102G. 2GSa/s 100MHz 2+1 channel. Using extra digital channel to trigger on SCK (SPI clock).
It would it nice to see the clock on an analog channel as well? :popcorn:
What's on channel 1? Is that just crosstalk?
Channel 1 is MISO (there is no Slave device connected to the ESP32 board who is acting as SPI Master)
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What's on channel 1? Is that just crosstalk?
Channel 1 is MISO (there is no Slave device connected to the ESP32 board who is acting as SPI Master)
Ok, so it's probably just crosstalk/coupling inside the ESP32.
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I'm guessing all the ringing is just from the probing method used? I'd be a little concerned seeing 0.5V of noise on a 3.3V signal.
Still glad to see that even with a high sampling rate, analog bandwidth will still bite me in the backside.
You are correct, I am using breadboard and standard ground loop
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Keysight EDUX1002G modded to DSOX1102G. 2GSa/s 100MHz 2+1 channel.
(https://www.eevblog.com/forum/testgear/rigol-ds1054-is-a-champion/?action=dlattach;attach=324550;image)
(https://www.eevblog.com/forum/testgear/rigol-ds1054-is-a-champion/?action=dlattach;attach=324552;image)
(https://www.eevblog.com/forum/testgear/rigol-ds1054-is-a-champion/?action=dlattach;attach=324554;image)
(https://www.eevblog.com/forum/testgear/rigol-ds1054-is-a-champion/?action=dlattach;attach=324556;image)
(https://www.eevblog.com/forum/testgear/rigol-ds1054-is-a-champion/?action=dlattach;attach=324558;image)
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It's interesting that in the Rigol, you can see the counting transactions ( Channel 2 blue ) and in Keysight you see a freeze counting value Showing that only 1 waveform is acquired while on Rigol was many, I guess was 32 since you can see a transition on 5 bit
I guess you use a too long GND path, try remake with all probes GND connect to the GND pin near the 0 button or right near PIN 21, there is a better and short GND who probably will make a more nice waveform, with less inductive effect on probe
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Are you using the original edux model probes? Weren't they only 70Mhz?
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Tk do you have access to a Siglent 100Mhz arb generator?
Would be interesting to make a comparative in another scenario based on signals from that generator
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Are you using the original edux model probes? Weren't they only 70Mhz?
I am using the 200MHz probes from the micsig. I will retest on the Keysight with the stock 70MHz probes.
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Tk do you have access to a Siglent 100Mhz arb generator?
Would be interesting to make a comparative in another scenario based on signals from that generator
I don't have a Siglent arb generator. I have a Rohde & Schwarz CMU200 with RF signal generator (up to 2.7GHz) and the EDUX1002G with 20MHz wavegen. I can do AM/FM modulation on both of them.
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I will retest on the Keysight with the stock 70MHz probes.
Keysight ships 70MHz probes? Seriously? How do they even manage to make them that bad?
There's a thread on here somewhere testing the cheapest cheap-ass Chinese probes ever and they were fine up to 300MHz.
https://www.eevblog.com/forum/reviews/cheapest-100mhz-oscilloscope-probes-hands-on-review/msg99256/#msg99256 (https://www.eevblog.com/forum/reviews/cheapest-100mhz-oscilloscope-probes-hands-on-review/msg99256/#msg99256)
Edit: I think we have the answer: https://www.eevblog.com/forum/testgear/new-keysight-scope-1st-march-2017/msg1220323/#msg1220323 (https://www.eevblog.com/forum/testgear/new-keysight-scope-1st-march-2017/msg1220323/#msg1220323)
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I will retest on the Keysight with the stock 70MHz probes.
Keysight ships 70MHz probes? Seriously? How do they even manage to make them that bad?
There's a thread on here somewhere testing the cheapest cheap-ass Chinese probes ever and they were fine up to 300MHz.
https://www.eevblog.com/forum/reviews/cheapest-100mhz-oscilloscope-probes-hands-on-review/msg99256/#msg99256 (https://www.eevblog.com/forum/reviews/cheapest-100mhz-oscilloscope-probes-hands-on-review/msg99256/#msg99256)
Edit: I think we have the answer: https://www.eevblog.com/forum/testgear/new-keysight-scope-1st-march-2017/msg1220323/#msg1220323 (https://www.eevblog.com/forum/testgear/new-keysight-scope-1st-march-2017/msg1220323/#msg1220323)
The link shows the Keysight 200MHz probe that is shipped with the DSOX1000 models. The EDUX1000 models ship with 70MHz probes because it is a 50Mhz scope.
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The link shows the Keysight 200MHz probe that is shipped with the DSOX1000 models. The EDUX1000 models ship with 70MHz probes because it is a 50Mhz scope.
All true, but irrelevant.
I'm just wondering how anybody manages to make a probe that only goes to 70MHz these days.
ie. Is it really possible to save enough money to make up for the extra costs of manufacturing/stocking multiple probes?
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ie. Is it really possible to save enough money to make up for the extra costs of manufacturing/stocking multiple probes?
Cynical Fungus might suspect they actually lose money by making really bad 70Mhz probes but make up for it by doubling or tripling the price of their 'premium' 300MHz probes.