REVIEW - Owon SDS7102 - A look at the SDS series from Owon

[wingel]

I've been a bit busy with work but finally found time to write a bit more about the SDS7102.

http://blog.weinigel.se/2016/05/27/another-look-at-sds7102-hardware.html   

[wingel]

And a bit more.

http://blog.weinigel.se/2016/05/28/sds7102-gio-pins.html
http://blog.weinigel.se/2016/05/29/sds7102-fpga-pins.html

Just a few more posts and I will have caught up to where I actually am.

[calin]

Holly $ht man !! you are really killing it. 


I do firmware stuff for a living too and I really enjoyed the read. Keep up the good work .. I have one of the scopes and if time (read that 2 kids) lets me I may join in the play

[qwertz]

Hi,

Really nice "work" !! Can't wait for the next episode

[wingel]

I've been a bit busy with work again, but finally found time to write a bit more about the scope.

http://blog.weinigel.se/2016/06/19/sds7102-more-fpga-pins.html

This is about as good as it gets I think.  I've figured out how most of the parts of the scope fit together and unfortunately I'm not sure if I'll ever be able to get the two DDR interfaces to work (one DDR interface to the Soc/CPU where the FPGA emulates a DDR memory, another DDR interface to a DDR memory chip).  Without these two parts the scope will never be able to update the screen quickly or store deep traces, but I'm probably still going to try to get the ADC to work and see if I can at least prove that everything works the way I think it does.

[wingel]

I lied.  I had a bit more material left in my notes.  Here's a short look at the front panel.

http://blog.weinigel.se/2016/06/21/sds7102-front-panel.html

[tpwire]

Hello,
I have an oscilloscope OWON SN: SD71021407245.  When I was updating the firmware, there was a problem with the power and now the screen flashes yellow.
Now when I connect the oscilloscope via USB to PC, nothing happens.

How I can fix it? Someone has a complete binary of memory?

Best regards.

[wingel]

I've managed to capture samples from the ADC:

http://blog.weinigel.se/2016/07/08/sds7102-capture.html

[nctnico]

Just to let you know I read your reports! 

[siggi]

This is way cool!


Sent from my iPad using Tapatalk

[CustomEngineerer]

Hello,
I have an oscilloscope OWON SN: SD71021407245.  When I was updating the firmware, there was a problem with the power and now the screen flashes yellow.
Now when I connect the oscilloscope via USB to PC, nothing happens.

How I can fix it? Someone has a complete binary of memory?

Best regards.

Read the last few pages of this thread. Pretty sure at least one other person reported having the same issue as well as what they did to fix it.

[tpwire]

Hello,
I have an oscilloscope OWON SN: SD71021407245.  When I was updating the firmware, there was a problem with the power and now the screen flashes yellow.
Now when I connect the oscilloscope via USB to PC, nothing happens.

How I can fix it? Someone has a complete binary of memory?

Best regards.

Read the last few pages of this thread. Pretty sure at least one other person reported having the same issue as well as what they did to fix it.

Hi, I've done a dump of another SD7102 and I use that binary to program my oscilloscope.

The result is that the screen is yellow. I have written to vas455 but I have not yet received a reply.

[wingel]

And a bit more:

http://blog.weinigel.se/2016/07/10/sds7102-soc-bus.html

Next up, controlling the analog frontend and the ADC.  I've mostly finished this but haven't written anything about it yet.

[Carrington]

This can be very helpful. A volunteer, to translate?
"tpwire" problem was solved using this info:
http://radiokot.ru/forum/viewtopic.php?p=2807326&sid=1f74f269e41f1a86c91f95d3faa7881e#p2807326


@ wingel (Christer)
What you're doing is amazing, thanks for sharing. 

[pascal_sweden]

Really nice project that you are doing there!

I actually consider to buy this scope, just to follow your project and play along at home It makes learning FPGA stuff just more cool!

After your project is finished, you should consider publishing a book, with all the findings, and you could sell it together with the scope in an educational bundle package =)

I've managed to capture samples from the ADC:

http://blog.weinigel.se/2016/07/08/sds7102-capture.html

[wingel]

One final post.  Or not.  Anyway, with this I have basically documented how everything in the scope fits together.

http://blog.weinigel.se/2016/07/15/sds7102-afe.html

[pascal_sweden]

In case I would buy this scope, to follow your project and play along at home, would it be possible for me, to open up the scope just once, mount the JTAG cable and other debugging cables into the scope, and after close it again?

This would keep my bench tidy, while at the same time I would have full access to the scope, to control and monitor it from the JTAG interface and the other debugging cables.

Owon SDS7102-D: D for debugging option =)

Maybe a small batch of these scopes can be produced, for an FPGA and DSP class room

Another option that I can see: Use everything from the scope, including the analog front-end, the controls and knobs, the display, the power supply, but bypass the main processor and insert a Xilinx Zynq-7000 instead. This could in fact be the Zybo board from Digilent. Would it be easy to redirect the output of the analog front-end? Or would it be possible to tri-state the main FPGA and take over control through a Xilinx Zynq-7000? Would there be space inside to add an extra Zybo board without replacing an existing board?

Using this modification, you could retro-fit the Owon scope and convert it into a powerful scope with super powers that beats the GW-Instek GDS-2000E

Owon SDS7102-Z: Z for Zynq-7000 option =)

Also here, maybe a small batch of these scopes can be produced, for an FPGA and DSP class room

[wingel]

If you aren't bored with me yet.

I've put the source code for my Linux port and FPGA image on github.

http://blog.weinigel.se/2016/07/16/sds7102-source.html

[wingel]

In case I would buy this scope, to follow your project and play along at home, would it be possible for me, to open up the scope just once, mount the JTAG cable and other debugging cables into the scope, and after close it again?

Yes, this is how my scope looked for the first few weeks, three wires for the 3.3V serial port (GND, Tx, RX) and a handful more of wires for JTAG (GND, VREF, TMS, TCK, TDI, TDO, RST).   I had to remove a bit of plastic to be able to bring the JTAG cables out of the unit.



Actually the boot loader protocol in the scope doesn't seem to be that complex so it should be possible to load Linux into flash on the scope using just a USB cable.  But that would be a one way street, it would overwrite the original OWON firmware in flash with no way of making a backup and I don't know if it's possible to restore the original firmware after doing that.

Another option that I can see: Use everything from the scope, including the analog front-end, the controls and knobs, the display, the power supply, but bypass the main processor and insert a Xilinx Zynq-7000 instead. This could in fact be the Zybo board from Digilent. Would it be easy to redirect the output of the analog front-end? Or would it be possible to tri-state the main FPGA and take over control through a Xilinx Zynq-7000? Would there be space inside to add an extra Zybo board without replacing an existing board?

I guess it would be doable in theory, the FPGA ought to three-state all pins if it's not configured, so it should be possible to  solder wires onto the SPI busses and chip selects and ADC wires.  In practice, no, the signal integrity of the ADC signals would be awful.  And there isn't space in there for an extra PCB anyway.

What would be doable would be to create a new main PCB with a Zynq, ADC, analog fronten and all the connectors on it and just reuse the front panel and LCD board.  But that would cost a lot and probably not be worth the time and money.  It would be a fun project though.

Actually my dream 1Gsps/100MHz scope would be something like that.  I like the form factor of the OWON scope, I like the screen and the physical layout, I like having a built in battery.  But it would be very nice with a Xilinx Zync or Altera Atlas with a lot more CPU power. a couple of hundred megabytes of sampling memory and  gigabit ethernet.

Anybody up for a kickstarter? :-)

[pascal_sweden]

I already suggested this in my separate thread about DSO manufacturers using the Xilinx Zynq-7000 series.

See my separate thread about this: Retrofit kit and open source bench oscilloscope
https://www.eevblog.com/forum/testgear/other-dso-manufacturers-besides-gw-instek-that-use-xilinx-zynq-7000-series/msg983966/#msg983966

You can compare it with some of the mountain bikes from the German company Bulls back in the days.
For 1000 EUR, you could get a mountain bike fully spec:ed with Deore XT parts, both in the front and the back. Some people just bought the mountain bike for parts. They would discard or sell the frame, and mount the parts on a new frame. This was much cheaper than buying the Deore XT parts yourself, even if you paid for a frame that you are not using, because Bulls had such a high turnover, they could buy these Deore XT parts in big quantities. Today, you can still buy such a mountain bike from Bulls with Deore XT parts at a similar price. But now people don't discard the frame anymore, because now the frame is premium as well

In the case of the oscilloscope, we would actually do the other way around. We only keep the build mechanics, the plastics, and the overall physical design. Chinese oscilloscope manufacturers, are extremely good at the build mechanics, the molding of the plastics, and the overall physical design. There is no way, to beat that as a small player. But on the electronics side however, it would be very feasible to spin your own PCB board, that adds super powers to your existing bench oscilloscope!

It would definitely be a nice Kickstarter project!

Where are you based in Sweden? I used to live in Linköping.

We could call the Kickstarter project as follows:
"The Scandinavian Retrofit Kit for a bench oscilloscope: Add Zynq-7000 super powers to your existing bench oscilloscope!" =)

But what base model should we select for the bench oscilloscope upgrade? We could go for a Rigol DS1054Z, as those are out there in the most quantities! Or do you suggest another base model?

BTW: One of my former colleagues works at a company in Linköping that is specialized in ADC technology.
One of the projects he worked on, was the design of a PCB board, for an entry level LeCroy oscilloscope,
that used the ADC technology from his company. Maybe we could use their technology for the PCB board

I can check with my former colleague, if he would be interested in helping out for, or being part of, such a Kickstarter project.

[nctnico]

Forget about connecting an ADC to a different board. The signals carry such high frequencies that it will not work over any kind of wiring. Besides that connecting the wires will be a nightmare as well. IMHO the best thing to do is create an entirely new board (analog frontend + digital parts) which fits in an existing scope case OR buy an existing scope which already has the hardware you like and reverse engineer that so it can run your own firmware. In that respect reverse engineering the Owon is a bit of a waste of time because creating a scope with decent performance in a reasonable timeframe will be very hard (if it is possible due to limited FPGA, bandwidth and processing resources).

[wingel]

The SDS7102 (or rather one of the cheaper models) would be a fairly nice scope for such a retrofit in that case since it is modular, you'd be able to keep the front panel and LCD boards and only have to replace the main PCB.   The Rigol 1054Z seems to be one big PCB so you'd have to replace everything.

I live in Stockholm, used to study in Linköping . Google my name, there's only one Weinigel in the whole of Sweden.  :-)

I might know your colleague too, there were a couple of guys from Admittansen that did rather groundbreaking work on time multiplexing/interleaving of ADCs in Linköping.

[EU1]

It seems that input attenuator of my scope went out of calibration.
An input attenuator in SDS7102 has 3 ranges: 1:1 (active when V/div is 100 mV/div or less), 10:1 (200 mV/div - 1 V/div), and 100:1 (2 V/div or above). Range is selected by relays, so when you change V/div you can hear if the range is changed.
Divider compensation is adjusted by C9 at 10:1 and by C10 at 100:1. - C9 and C10 would not cause such a sharp overshoot, so probably they are correctly adjusted.

On da_1.png the same signal is measured on 100 mV/div (1:1) and on 200 mV/div (10:1). You can see that at 1:1 (100 mV/div) square wave is really square, so the amplifier works correctly, but at 10:1 (200 mV/div) the attenuator is overcompensated. Switching between 10:1 and 100:1 shows that at 100:1 compensation is even worse comparing to 10:1.

The same problem is on both channels.

Has anybody a similar problem?

[pascal_sweden]

What if we keep the existing PCB board, and use the existing FPGA as a gateway towards the new PCB board? This way we would not affect the original ADC circuitry, while at the same time still have access to it!

Forget about connecting an ADC to a different board. The signals carry such high frequencies that it will not work over any kind of wiring. Besides that connecting the wires will be a nightmare as well. IMHO the best thing to do is create an entirely new board (analog frontend + digital parts) which fits in an existing scope case OR buy an existing scope which already has the hardware you like and reverse engineer that so it can run your own firmware. In that respect reverse engineering the Owon is a bit of a waste of time because creating a scope with decent performance in a reasonable timeframe will be very hard (if it is possible due to limited FPGA, bandwidth and processing resources).

[wingel]

What if we keep the existing PCB board, and use the existing FPGA as a gateway towards the new PCB board? This way we would not affect the original ADC circuitry, while at the same time still have access to it!

Then you'd have to go through the existing SoC.  You might as well just talk to the scope over ethernet and you won't have fast access to the data in the FPGA.  I think you either make do with what the existing hardware can do or you have to bulid a new main PCB.

I'm planning for the first, see what I can do with the existing hardware.   If that works out fine and I somehow get a lot of money it would be fun to try to replace the main board, but I don't think that'll happen.