Cheap logic analyzer - similar types but with different components - which one? - Page 1
Forum section: electronics / testgear

author: Rinnake
author_rank: Contributor
timestamp: February 01, 2021, 07:16:16 pm
content: Hello.I'd like to buy a cheap logic analyzer but I do not know which one to choose.When I was searching the analyzer I found very similar, but different from each other (different components used). Some analyzers reportedly lack a buffer for 24M sampling. For some types, I can't find out. :First:https://www.banggood.com/USB-Logic-Analyzer-24M-8CH-Microcontroller-ARM-FPGA-Debug-Tool-p-1177821.html?cur_warehouse=CN&rmmds=searchOther:* In the review of this product, one buyer writes:"The version this seller ships is the one with the LVC245A buffer. Thank you, seller.":https://www.aliexpress.com/item/1005001281306291.html?spm=a2g0o.detail.1000014.39.7c885dc8qrqQ8P&gps-id=pcDetailBottomMoreOtherSeller&scm=1007.13338.183346.0&scm_id=1007.13338.183346.0&scm-url=1007.13338.183346.0&pvid=1ad20c8a-ee06-48f1-95cb-0911de6a14fa&_t=gps-id:pcDetailBottomMoreOtherSeller,scm-url:1007.13338.183346.0,pvid:1ad20c8a-ee06-48f1-95cb-0911de6a14fa,tpp_buckets:668%230%23209439%233_668%23888%233325%232_3338%230%23183346%230_3338%233142%239890%237_668%232846%238114%231999_668%232717%237558%23162_668%231000022185%231000066058%230_668%233422%2315392%23540Similar (but I'm not sure if they have a buffer):https://www.aliexpress.com/item/4000498763030.html?spm=a2g0o.productlist.0.0.4e09de5dvPvGlK&algo_pvid=e01c0a4c-dc8e-418a-87f9-8e34d042c574&algo_expid=e01c0a4c-dc8e-418a-87f9-8e34d042c574-4&btsid=2100bb4916122007339174401e033a&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_and:https://www.aliexpress.com/item/4001209621783.html?spm=a2g0o.detail.1000014.31.7c885dc8qrqQ8P&gps-id=pcDetailBottomMoreOtherSeller&scm=1007.13338.183346.0&scm_id=1007.13338.183346.0&scm-url=1007.13338.183346.0&pvid=1ad20c8a-ee06-48f1-95cb-0911de6a14fa&_t=gps-id:pcDetailBottomMoreOtherSeller,scm-url:1007.13338.183346.0,pvid:1ad20c8a-ee06-48f1-95cb-0911de6a14fa,tpp_buckets:668%230%23209439%233_668%23888%233325%232_3338%230%23183346%230_3338%233142%239890%237_668%232846%238114%231999_668%232717%237558%23162_668%231000022185%231000066058%230_668%233422%2315392%23540Which one would you choose and why? This analyzer should be used for home projects.Thanks a lot for your answers.

author: rvalente
author_rank: Frequent Contributor
timestamp: February 01, 2021, 07:20:26 pm
content: Did you check sigrok wiki? A lot of useful info on LAs.

author: ataradov
author_rank: Super Contributor
timestamp: February 01, 2021, 09:33:46 pm
content: The buffer is not needed for 24 MHz sampling. 24 MBytes are just sent over USB, there is no buffering, USB HS has enough bandwidth.LVC245A is the transceiver that allows 5V tolerant inputs. And there is absolutely no way to tell what you will get.From what I can tell, most of those cheap logic analyzers have the transceiver. I personally have not seen one that would be so cheap to eliminate it.

author: Venturi962
author_rank: Regular Contributor
timestamp: February 01, 2021, 09:49:28 pm
content: My guess is that all of those options are based on an older Saleae LA using the Cypress FX2 chip.Hardware is detailed here:

author: rvalente
author_rank: Frequent Contributor
timestamp: February 02, 2021, 12:11:23 am
content: Mine cheapo saleae clone works fine up to 4Msa/s after than that salea logic throughs a usb errorMaybe a low quality usb cabe, dunno.For me is usable

author: Gyro
author_rank: Super Contributor
timestamp: February 02, 2021, 10:13:55 am
content: Quote from: Venturi962 on February 01, 2021, 09:49:28 pmThe original Saleae didn't bother with a buffer, the inputs went into the FX2. It was just the Cypress reference design. It did have a nicely milled Aluminium case though.http://www.eevblog.org/video/EEVblog436-SaleaeLogic8review-640x360.m4v

author: gnuarm
author_rank: Super Contributor
timestamp: February 02, 2021, 11:00:09 am
content: I don't know anything about these devices, but I know the important part (just as important anyway) is the software. Without decent software on the computer these things are crap. I bought a Hantek oscilloscope and LA and the software won't even run.

author: Gyro
author_rank: Super Contributor
timestamp: February 02, 2021, 11:28:06 am
content: Those USB Hanteks (6022BL?) were crap in pretty much every respect - someone around he wrote replacement S/W for the scope part which makes them more useable. Irrc, the LA part is just another generic FX2 app circuit copy - it probably works with Sigrok, maybe even Saleae.

author: Rinnake
author_rank: Contributor
timestamp: February 02, 2021, 01:17:28 pm
content: Thank you. I just found a clone of this device:CY7C68013A-56 EZ-USB FX2LP USB:https://www.ebay.com/c/12003531321(orhttps://www.banggood.com/EZ-USB-FX2LP-CY7C68013A-USB-Core-Board-Development-Board-Logic-Analyzer-p-1183409.html?akmClientCountry=CZ&rmmds=search&act_poa=SKU665589&cur_warehouse=CN)It seems to have more outputs and more memory, but I don't know if it would be better than a Saleae clone.

author: ataradov
author_rank: Super Contributor
timestamp: February 02, 2021, 05:06:31 pm
content: This is just a generic breakout board for that MCU. The actual number of channels is defined by the firmware, and most of the logic analyzers will give you the same 8 channels."Memory" does not matter, it is the size of the EEPROM that contains the firmware. In most cases the firmware loaded over USB into SRAM directly anyway, so the sizer of the on-board EEPROM does not matter.You are overthinking this. Just get literally any of those things. They are all the same. And at least the actual logic analyzer ones have plastic case and a good location for the inputs. On a dev kit the inputs will be all over the place on those connectors.

author: Gyro
author_rank: Super Contributor
timestamp: February 02, 2021, 07:58:16 pm
content: +1 The presence of the buffer doesn't affect anything in practical terms.

author: horo
author_rank: Regular Contributor
timestamp: February 04, 2021, 09:12:02 am
content: Quote from: Gyro on February 02, 2021, 11:28:06 amIt's me ->https://github.com/OpenHantek/OpenHantek6022"OpenHantek6022 is a DSO software for Hantek USB digital signal oscilloscopes 6022BE / BL. Development OS is Debian Linux, but the program also works on FreeBSD, MacOS, RaspberryPi and Windows".The LA is out of my scope, but it works with sigrok.