EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: Rinnake on February 01, 2021, 07:16:16 pm
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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=search
(https://www.banggood.com/USB-Logic-Analyzer-24M-8CH-Microcontroller-ARM-FPGA-Debug-Tool-p-1177821.html?cur_warehouse=CN&rmmds=search)
Other:
* 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%23540 (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%23540)
Similar (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_
(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%23540
(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%23540)
Which one would you choose and why? This analyzer should be used for home projects.
Thanks a lot for your answers :-+.
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Did you check sigrok wiki? A lot of useful info on LAs.
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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.
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My guess is that all of those options are based on an older Saleae LA using the Cypress FX2 chip.
Hardware is detailed here: https://www.youtube.com/watch?v=dobU-b0_L1I (https://www.youtube.com/watch?v=dobU-b0_L1I)
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Mine cheapo saleae clone works fine up to 4Msa/s after than that salea logic throughs a usb error
Maybe a low quality usb cabe, dunno.
For me is usable
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My guess is that all of those options are based on an older Saleae LA using the Cypress FX2 chip.
The 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 (http://www.eevblog.org/video/EEVblog436-SaleaeLogic8review-640x360.m4v)
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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. :--
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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.
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Thank you. I just found a clone of this device:
CY7C68013A-56 EZ-USB FX2LP USB:
https://www.ebay.com/c/12003531321
(https://www.ebay.com/c/12003531321)(or https://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 (https://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.
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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.
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+1 The presence of the buffer doesn't affect anything in practical terms.
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... someone around he wrote replacement S/W for the scope part which makes them more useable.
It'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.