How good is Analog Discovery 2's logic analyzer compared to dedicated one ? - Page 1
Forum section: electronics / testgear

author: xani
author_rank: Frequent Contributor
timestamp: September 14, 2017, 07:16:00 am
content: So I'm considering buying a logic analyzer (mostly for protocol decode, my scope can't do it) and stumbled upon Analog Discovery 2.Seems to be very similarly priced to equivalent salae gear (biggest difference being not accepting 5V input but I can live with that) but about half of its features I have already covered in other gear (I've got scope, generator, power supply, all better than what AD2 offers), altho I will probably find use for spectrum/network analyzer in near future.Is there any "catch" I'm unaware of ?

author: MrW0lf
author_rank: Frequent Contributor
timestamp: September 14, 2017, 07:36:47 am
content: Catch is called "Digital Discovery" (5V compatible if dig specs), it lacks every feature you do not need except SA

author: xani
author_rank: Frequent Contributor
timestamp: September 14, 2017, 07:51:02 am
content: Well if I wanted to save few bucks I'd just pick up some cheapo clone that aliexpress is filled with.Extra analog input is a feature for me (and salae has it too), it wont replace the scope but I will certainly find an use for it.Also, digital discovery is also max 3.3V, just 32 channel.I was wondering more about how good the software is compared to "proper" logic analyzer

author: Fungus
author_rank: Super Contributor
timestamp: September 14, 2017, 07:55:38 am
content: You can get simple LAs for $6 on eBay/aliexpress, so...Quote from: xani on September 14, 2017, 07:51:02 amYou can use sigrok with them so no worries.https://sigrok.org/wiki/ARMFLY_Mini-Logic

author: MrW0lf
author_rank: Frequent Contributor
timestamp: September 14, 2017, 08:01:34 am
content: Quote from: xani on September 14, 2017, 07:51:02 amDo you ever read specsin detail?https://reference.digilentinc.com/reference/instrumentation/digital-discovery/reference-manual"Setting the voltage to 3.3V, 5V logic inputs are tolerated but the input threshold is 1.42V. LVCMOS 3.3V output signals arecompatible to most external logical circuits supplied with 5V"Also whole unit is massively superior to AD2 in digital domain. 100MSa/s vs 800MSa/s max.Software is good, but different to Saleae one. Download and compare.Also is operating principle since DD has 2Gbit onboard memory while Saleae has none.As side note I have both AD2 and DD but never use either one for decoding because so far my scope has done the job

author: xani
author_rank: Frequent Contributor
timestamp: September 15, 2017, 10:26:31 am
content: Quote from: MrW0lf on September 14, 2017, 08:01:34 amNo, I do not read whole huge page (with relevant info at the very end of it) of specs for device I was not interested in the first placeQuotesadly my Rigol 1052E doesn't even have an option to do that.I guess I'll buy some aliexpress cheapie and see what I'll be missing

author: TK
author_rank: Super Contributor
timestamp: September 15, 2017, 10:35:11 am
content: What protocols do you work with? Zeroplus Logic Analyzers offer over 100 free protocols. Cannot do analog input but you already have scope for that.

author: MrW0lf
author_rank: Frequent Contributor
timestamp: September 15, 2017, 03:57:49 pm
content: Quote from: xani on September 15, 2017, 10:26:31 amSuggest to do so because before buying something should at least understand basic type of operation and general specs. To me saying you want logic analyzer, being interested in AD2 but not in DD is just plain absurd. Unless you actually are after NA part mostly.And why is it so?Saleae type analyzers stream, they do not have memory. Some originals stream fast but cost too much. Clones are cheap and slow.AD2 will stream but a laughable speed (~2MSa/s according to some forum, not checked), onboard memory is128KbitsDD should also stream at same speed (?) but onboard memory is 2Gbit=2097152KbitsAD2/DD have some serial trigger but AFAIK not reliable. Saleae have none when last checked.Only large memory can serve as bandaid.So unless doing some very basic stuff both Saleae clones and AD2 are fairly limited. However clones are cheap and AD2 is expensive + 128Kbits is in joke class nowdays.Maybe shall do shootout someday, I have those USB boxes more than can count - but Saleae (clone) missing from inventory - maybe should check out whats all the fuss about.

author: xani
author_rank: Frequent Contributor
timestamp: September 17, 2017, 09:19:08 am
content: I was interested in them in the first place because after thinking a bit of what I do the most.A lot of times I was writing some tiny arduino code just to flip some bits in order or to send few serial commands. And that one time when I was bored and tried to control neopixels using signal generatorI thought that ability to generate and receive signals in the same box.Quote from: MrW0lf on September 15, 2017, 03:57:49 pmIt would certainly be interesting ones. I think the fuss is just saleae having nice and shiny software that you can download and use with your cheapie.

author: MrW0lf
author_rank: Frequent Contributor
timestamp: September 17, 2017, 03:09:33 pm
content: Quote from: xani on September 17, 2017, 09:19:08 amDD has pattern gen also btw.Quote from: xani on September 17, 2017, 09:19:08 amWhich a bit evil of course... But solely for evaluation purposes "16 Channel USB Logic Analyzer USB 100MHz" clones seem to suit well. 24MHz ones may be too slow even for Arduino stuff when all channels in use.Otherwise have ADALM2000 on order since august but doubt that will see it anytime soon + software probably extra raw.