Author Topic: MSO2072A vs DS2072A + USB Logic Analyzer  (Read 2016 times)

0 Members and 1 Guest are viewing this topic.

Offline nbritton

  • Frequent Contributor
  • **
  • Posts: 436
  • Country: us
MSO2072A vs DS2072A + USB Logic Analyzer
« on: September 14, 2015, 03:59:10 AM »
In eevBLAB #5 Dave expressed his thoughts on MSOs, stating that they're the "ducks guts" when properly designed. However, he was also very clear that the MSO on the 1054Z is worthless and that you should get a separate USB logic analyzer if you go that route. He did not express any opinions on the MSO option on the 2072A. Is the MSO option on the 2072A worth it? Over at tequipment.net with the eevblog discount the DS2072A is $789 and the MSO2072A is $1,165. The price difference, i.e. the cost of the MSO option, is $376.

The Saleae Logic Pro 16 is $599. According to the datasheet the Saleae Logic Pro 8/16 are only capable of 500 MS/s on 4 channels, when using more than 4 channels it drops down to 100 MS/s.

Here is Dave's original video:
« Last Edit: September 14, 2015, 06:45:24 AM by nbritton »
 

Offline bson

  • Supporter
  • ****
  • Posts: 739
  • Country: us
Re: MSO2072A vs DS2072A + USB Logic Analyzer
« Reply #1 on: September 14, 2015, 04:46:39 AM »
Does the Selae Pro have a trigger out?  If not, it's still pretty useless since you won't be able to trigger the scope on decoder output.  For example, if the decoder sees an irregular invalid bus event you won't be able to correlate it with anything on the scope to determine why.  Is it really a firmware problem or is it due to noise, signal levels, a glitch, overshoot, waveform distortion, or anything else?  If it's capacitively coupled, where does it originate?  When this happens you'll want to inspect the waveforms on the scope in more detail first before going off and try to figure out what's wrong with the firmware.  Otherwise you may find that just randomly changing something "fixes" it and you have no idea why, and in fact all you may have done is shift the problem somewhere else.
« Last Edit: September 14, 2015, 04:48:38 AM by bson »
<This space intentionally left blank>
 

Offline IDEngineer

  • Contributor
  • Posts: 49
  • Country: us
Re: MSO2072A vs DS2072A + USB Logic Analyzer
« Reply #2 on: September 14, 2015, 12:03:06 PM »
Off-Topic: Anyone else notice that eight inch floppy disk in the upper left corner of Dave's video? Good old Shugart 801R disk drives....
 

Offline Ivan7enych

  • Regular Contributor
  • *
  • Posts: 131
  • Country: ru
    • My astronomy projects
Re: MSO2072A vs DS2072A + USB Logic Analyzer
« Reply #3 on: September 14, 2015, 05:56:13 PM »
It's different things.

Saleae is a good offline analyzer. It has more protocols, but it's not realtime, it can't show what's happening on the bus now.

MSO has a bit slow and limited decoding, but it has hardware realtime (with no slowdown) triggering on some events in the protocol (for example trigger on specified address in i2c command). And you always see sincronized in time both digital and analog chanels (which is impossible with external analyzer).

So the choice depends on what you need. If you need to capture single event and decode kilobites of data in it, the Saleae would be much better here.

I have both, MSO2072 and simple Saleae 8, and in the last year I had no intension to use Saleae, MSO does all what I need.
« Last Edit: September 14, 2015, 06:01:09 PM by Ivan7enych »
 

Offline kripton2035

  • Super Contributor
  • ***
  • Posts: 1386
  • Country: fr
    • kripton2035 schematics repository
Re: MSO2072A vs DS2072A + USB Logic Analyzer
« Reply #4 on: September 14, 2015, 06:43:33 PM »
would it be possible to have a software that records the datas of the MSO on the computer, in "real-time" via the lan interface ?
so use the mso directly for simple usage, and a software to analyze big amount of datas ?

Offline Karel

  • Frequent Contributor
  • **
  • Posts: 938
  • Country: 00
Re: MSO2072A vs DS2072A + USB Logic Analyzer
« Reply #5 on: September 14, 2015, 07:25:16 PM »
would it be possible to have a software that records the datas of the MSO on the computer, in "real-time" via the lan interface ?
so use the mso directly for simple usage, and a software to analyze big amount of datas ?

Not realtime. Protocol decoding in pc-software can be done but is extremely slow.
The workflow:
1. set the scope memory depth to anything but auto.
2. start an acquisition
3. stop the acquisition
4. download the deep memory data to the pc, either via USB or LAN, depending to the memory size this can take up to more than a minute
5. decode and visualize the data

It can be done almost "realtime" when you download only the display data. In that case you can only decode very short traces...


The difference between theory and practice is less in theory than
the difference between theory and practice in practice.
Expensive tools cannot compensate for lack of experience.
 

Online Fungus

  • Super Contributor
  • ***
  • Posts: 6334
Re: MSO2072A vs DS2072A + USB Logic Analyzer
« Reply #6 on: September 14, 2015, 07:35:22 PM »
Ignore the features for a moment: The choice is really down to whether you have a PC/laptop on your workbench or not.

If you do you should probably get a logic analyzer + DSO.

If you don't, there's not much point in arguing about features.

 

Offline alank2

  • Super Contributor
  • ***
  • Posts: 1631
Re: MSO2072A vs DS2072A + USB Logic Analyzer
« Reply #7 on: September 14, 2015, 10:45:14 PM »
I really wanted to love the MSO.  I had an original Rigol with MSO and I captured some HD44780 stuff I was working on with it.  While it did work, it was tedious and slow.  When I upgraded to a DS2072, I was anxious to check out the decoding, but it was extremely disappointing.  It would only decode what is on the screen and if you scroll part of a frame off the screen it would screw up the alignment of other frames.  It was slow and cumbersome.  Trying to capture an entire stream of any length is also a challenge, you have to shorten up the time base to try to get it all on one screen which can be a pain because you won't see it trigger until the center of the screen unless you push the trigger almost all the way to the left, do an acquisition, and then zoom into it all.  I don't see how recording multiple triggers is going to improve this, but I want to capture what happened and then look at it.

This is where a USB style LA is ideal for me.  Set the capture rate and in the case of the Saleae, how much time you want to capture for, perhaps even a simple trigger if you will be repeating the capture and want it to find the same location again and again between events.  Once you have the capture, you can do all you want to it.  It has 23 or so different decoders.  Add them, tweak them, remove them, etc.  You can save the capture and share the entire thing with others easily.  They can add decoders or tweak them.  They can scroll around the entire capture easily, add measurements, etc.

If it came down to it, I'd much rather have even the original 24MHz 8 channel Saleae than a MSO2072.  I would be done troubleshooting what I wanted on it before I would even get the MSO setup properly.

Now, if the price of the MSO and DSO were so close that it wasn't much difference, I'd take the MSO for its extra ability, but I'd only use the MSO if it were as efficient as my other tools.
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf

 

http://opalkelly.com/