Real logic analyser board teardown - Page 1
Forum section: electronics / testgear

author: free_electron
author_rank: Super Contributor
timestamp: July 10, 2013, 06:39:07 am
content: As opposed to the USBee , Salae , Logicport and al the other wannabe's : this is a board from a real logic analyserpicture 1 : the board : 68 channels , 400 MHz state , 2GHz timing , 4 Megasamples per channel. 5 of these boards can be synced up using special cables and interconnect blocks. the flatcable top right is used as a timing aligner while the white connectors above and below the heatsink go form board to board to carry the trigger qualifier signals.picture 2 : the input stage. the signals come in over the ribbon coax cables 9 gthe flatcabels coming out of this board are actually a bundle of coax cables ) and go into a termination chip . these chips contain the fast comparators with programmable threshold and hysteresis. the bigger chips contain a fifo that brings out the captured data over a slower but wider bus.picture 3 : the trigger processors. these are big asic's that essentially contain a simplistic custom processor. this processor runs in lockstep with the incoming data and executes the trigger conditions. these monsters can do very complex triggering they handshake amongst each other and talk to their counterparts on expander boards to make essentially a VLIW processor. you can do things like-find pattern p or pattern q, wait 3 clockticks ,if pattern y is detected wait1 clocktick and see of pattern z comes by. then trigger. if no patterny comes by but pattern p restarts : trigger.these machines can also trigger on glitches, pulses that are too short , too long or on misaligned pulses ( like setup and hold time violations in respect to the clock )picture 4 : the custom memory controller that handles the sdram. built in (for that time) very expensive FPGA's. depending on the board version you can have 4 , 16 or 32 meg ram. it's a matter of loading different fpga code. i suspect part of the advanced timing processor also sits in the fpga's. depending on what module you run in the LA software they load different fpga config files...These boards were , new ( 10 years ago) about 32.000 $ ... i have 3 of these in my analyser. (16702B). over the weekend i will upgrade my analyser to a 16900A at which point is will show a more detailed teardown of the entire machine...

author: Carrington
author_rank: Super Contributor
timestamp: July 10, 2013, 10:36:35 am
content: Hi free_electron, good pictures.How much it cost one of these?Where did you buy it?

author: poodyp
author_rank: Regular Contributor
timestamp: July 10, 2013, 10:50:25 am
content: 68 channels * 5? What on earth would you use 340 logic channels with? I'm genuinely curious.Now that I think about it I remember seeing someone with a crazy setup in a massive rack, but I forget what it was used for.

author: free_electron
author_rank: Super Contributor
timestamp: July 10, 2013, 02:25:57 pm
content: The new boards are 102 channels. You can have 6 in the 16900a and another 6 in the expander chassis. For the older 16700 series its 5 and 5.My machines came from intel... I think that speaks for itself.... I have a breakout adapter for the pentium 3 processor... Plonk it in the socket, put cpu on top and the analyser traces all the pins of the cpu in realtime... Simce that chip has 370 pins you need a machine with 'balls'...This board came with my analyser. I paid a whopping 300$ for the analyser and it included 3 of these cards... The machine runs hp-ux and has a large touchscreen. I scored a 16900 a couple of months ago. The boards are compatible. I will transplant over the weekend and then sell off the 16702b. The 16900 runs windows and uses a standrd pc motherboard. The 16700 is a pa-risc based machine.I will install a larger harddisk in the machine and do a fresh install of the OS. I have the disk images.

author: Carrington
author_rank: Super Contributor
timestamp: July 10, 2013, 02:41:12 pm
content: Quote from: free_electron on July 10, 2013, 02:25:57 pmWow! On eBay cost much more. For $ 300 I also want one, but I can not find.

author: Fraser
author_rank: Super Contributor
timestamp: July 10, 2013, 06:06:38 pm
content: Very nice Logic AnalyzerI was very tempted to follow that path, but I am a repair tech rather than a developer so my needs were less demanding. For anyone involved in development work, such a well designed machine would be superb. They built things to perform and last in those days.With regard to the number of channels....I have only 32 on my Hantek 4032L and it is a toy in comparison. I am fault tracing on a high density MC68340 embedded computer that has all manner of A to D and video processing hanging off of the data and address busses. Some even have their own discrete 'closed loop' busses. All ,interact and a failure in any brings the whole party to a HALT ! I can see that it would be great to monitor the CPU data, address and control busses plus the activity on the peripheral glue logic and dedicated task hardware. I could easily use up at least two hundred channels if not more !I do have a question though....I am working on fine pitch smt chips and have tried using the good quality HP and Tektronix SMD grabbers...they are totally useless in my case as the SMD lead pitch is too small. You can't even attach one grabber without shorting to adjacent pins. How do professionals attach to such fine pitch chips please ? I looked for header clips like I used on DIL chips but no joy. (probably mega bucks anyway) I am considering soldering individual insulated wire wrap wires to each pin and bringing them out to a prototype PCB fitted with lots of PCB pins for grabber attachment. The capacitance and inductance effects will be awful, to say nothing of RFI risks ! It is only fault tracing though.

author: c4757p
author_rank: Super Contributor
timestamp: July 10, 2013, 06:10:41 pm
content: Quote from: free_electron on July 10, 2013, 02:25:57 pmWow.An analyzer that can trace the entire set of signals passing through the pins of a Pentium 3 is truly impressive. Balls indeed.

author: marshallh
author_rank: Unknown
timestamp: July 10, 2013, 06:38:28 pm
content: If you look carefully you can snag some of those cpu interposers on Ebay. They were made specifically for a particular LA usually.More pins = better. IMO it's completely ludicrous you could buy a $10k scope and not get any more than 16 channels. Completely useless. What if you need to debug a 64bit interface with control signals? These things do exist.

author: free_electron
author_rank: Super Contributor
timestamp: July 10, 2013, 07:19:49 pm
content: Quote from: c4757p on July 10, 2013, 06:10:41 pmthe newer 16902 and AXIe machines have boards that can go even much faster ... those are used to design the Core-2 and more modern processors. A fully built out machine can trace a quad core with 1500 + pins in real time, it won't even blink....i am not even going to try to guess what such a setup costs....-edit- i just looked.... roughly 1000$ per channel ....Image what a setup would cost to trace a quad core machine ? Agilents flagship can track in state mode at up to 4Gbyte/s and in timing it works below 100pS ... that stuff is beyond black magic ....Throw in a memory buffer that can store 400 Megasamples per channel... You may as well be listening to the famous 'brown note', the end result will be the same.http://www.home.agilent.com/en/pd-1970950-pn-U4154A/4-gb-s-axie-based-logic-analyzer-module?nid=-536902443.974119&cc=US&lc=engThis is my new toy :http://www.home.agilent.com/en/pd-352508-pn-16900A/logic-analysis-system?cc=US&lc=engto give you an idea of what a real logic analyser can do and is used for :http://www.home.agilent.com/agilent/editorial.jspx?cc=US&lc=eng&ckey=465374&nid=-536902551.536883657.00&id=465374So the next time someone calls the USBee or Salae a 'Logic Analyzer' you are permitted to laugh out loud... Not only are they not close , they may as well be in a different solar system .

author: c4757p
author_rank: Super Contributor
timestamp: July 10, 2013, 07:32:32 pm
content: Quote from: free_electron on July 10, 2013, 07:19:49 pmErm.... do those numbers mean what I think they mean?

author: Bored@Work
author_rank: Super Contributor
timestamp: July 10, 2013, 08:19:34 pm
content: This is like arguing a 72" wrench is the only wrench good enough for all jobs:While in reality the tool has to fit the job.

author: free_electron
author_rank: Super Contributor
timestamp: July 10, 2013, 09:15:15 pm
content: ooh. now there's a wrench ... do they make hammers too ? i'd love to have a 6 foot hammer. great to widlarize stubborn components

author: SeanB
author_rank: Super Contributor
timestamp: July 11, 2013, 03:54:30 pm
content: 4lB and a old railway slipper works for me. they go very flat and tend to become a conformal coating on the shoe.I don't have the big adjustable wrench, but a smaller 50mm one, which is perfect for some nuts, either you undo them or sheer the bolt off.

author: nctnico
author_rank: Super Contributor
timestamp: July 11, 2013, 10:47:04 pm
content: More porn: a Tektronix TLA7AA4 acquisition module. These boards have 134 channels with 32Mbit per channel and each sample has a 52 bit timestamp. The sampling rate is 8GHz and each channel has a 'short' 16k memory sampled at 8Gs/s. The main memory can be used in several ways: full width at 500MHz, half width at 1GHz and quarter width at 2GHz. The memory length goes up as well so at 2GHz it can hold 128Msamples. As an additional bonus every channel can be routed to one of the 4 BNC connectors so you can watch the signal on an oscilloscope as well. This is a pretty cool feature which I like to use a lot.There are two boards: the CPU board which communicates with the logic analyser over a VXI (VME-ish) bus and the acquisition board. The acquisition board is a 3mm thick PCB with BGA components on both sides. The casing has special ducts to direct the airflow. There is about 200MB of DDR memory on the board. These modules have a list price around US $79000 with the 32Mbit/channel option.

author: free_electron
author_rank: Super Contributor
timestamp: July 12, 2013, 01:23:38 am
content: drool ....