Saleae Logic

[Alex]

How about a review of the SaleaeLogic analyser/serial bus decoder? It certainly is a very interesting product.

http://www.saleae.com/home/

[frank26080115]

I like it, I have two now, one of them is a clone that only costs $50 instead of $150 http://iteadstudio.com/store/index.php?main_page=product_info&cPath=29_31&products_id=221

The software makes it more preferable over Open Logic Sniffer, which I also have but never use (because of the software).

Some people have complained about the computer not being able to keep up with the Saleae's maximum sample rate, but my computer is decent and it's never bothered me.

[Alex]

Surely the maximum data transfer rate is equal or less to USB 2.0 specs. I dont see how a modern computer cannot keep up with that.

I am also puzzled by the architecture. Is the device sampling at the frequency and duration specified in the software and streaming to the PC? Is there any buffering taking place? Can you create triggers on specific data packets?

Would I be asking for too much if I asked for a couple of pictures of the internal circuit, please?

EDIT: Cancel that:

http://hackaday.com/2009/03/06/tools-saleae-logic-logic-analyzer/#more-8836

[alm]

Surely the maximum data transfer rate is equal or less to USB 2.0 specs. I dont see how a modern computer cannot keep up with that.

It needs a sustained transfer rate, USB was not designed for this, especially in bulk transfer mode (it's designed for things like mass storage devices, which can wait). Some computer chipsets are better at this than others.

I am also puzzled by the architecture. Is the device sampling at the frequency and duration specified in the software and streaming to the PC?

The hardware just transfers bytes (8-bit = 8-channel wide) at the specified rate to the PC. The PC does all work like triggering and decoding.

Is there any buffering taking place?

Very little, which is why USB transfer rate can be an issue. I personally didn't have any problems achieving the full 24MS/s on two computers.

Can you create triggers on specific data packets?

I believe advanced triggering is still work in progress. The current software supports basically a one-stage edge/pattern trigger. You can download the software and run it in demo mode without the hardware to try it.

Would I be asking for too much if I asked for a couple of pictures of the internal circuit, please?

The Sigrok website has some. Not much to see, just an MCU with USB interface in DMA mode. Most of the complexity is in the software, so clones (which supply their own hardware but use the original software) are a significant issue.

[epokh]

Hello guys,
this an interesting topic.
I'm actually working on essentially a similar device called Bug Logic 2.
It has the same specs of the Saleae logic but I'm working to develop an open source firmware for
the Cypress chip.
http://buglogic.robomotic.com/tiki-index.php
I'm selling it at 25.00 pounds and the profit is pushed for the software development.
The main issue with current usb based chip yes is the transfer rate,
I'd love to see a PCI or AGP based pod in the future.
P.S.
You can find plenty of clones in the chinese market.
:-)

[Fraser]

epokh,

Your post interested me so I took a look at your site. Very interesting.

I went to order one at £25 but after "extras" it's actually £36.

Is this your unit for sale with free shipping and a cost of only $39.90 delivered? :

http://www.aliexpress.com/product-gs/424564397-Saleae-Usbee-Clone-Logic-Analyzer-Aluminum-Case-Free-Shipping-WB078-wholesalers.html

I would buy direct from you if you offer it delivered to the UK at $40.00 as advertised above.

[epokh]

Yes I  believe is probably the same but certainly not the same supplier.
Yes I'm still fiddling with the shop options cannot get the shipping right.
For uk delivery is 25+4 pounds royal mail, I can send you a paypal request directly.
I test the boards individually you can try to buy from him if you believe is a better deal.
As I said i'm not doing it as a business :-)

[Fraser]

epokh

Understood  

£25 + £4 postage is very fair.

I will PM you.