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???
03/08/06 17:21
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#111625 - better mousetrap
Responding to: ???'s previous message
" Well ... logic analyzers are popular topics. The guys who don't have one want to build one, and the guys who have one want to build a better one. Go figure!"

Richard, I'm in the latter category. I started with the old-skool HP1630/1631 (never turn it off or it loses your setup since management never bought the GPIB tape or disk drive!), then got into 16500s (I have a 16500A boat-anchor in the closet, fully loaded, software disks, too--who wants it?), 1650s, and now I have a 1661E which is very nice. My biggest complaint with all of them is that they take up too much desk space. Who needs a display and a user interface and storage when I have a PC (errr, more than one PC) on the desk as well? All I want is a small interface pod with cables that hooks up to the PC (or my Mac, dammit!). Oh, yeah, Agilent has one, but it's expensive. So do others, but they're not fast enough, or not flexible.

The other "problem" with the instruments I mention above is that there's no was to program them for specific protocols. I2S, I2C, SPI, PCI, even USB would be nice, but there's no programmer API for them. Perhaps such exists on the newer 1680 and 1690 models but I haven't looked. So having a generic high-speed capture device with a flexible trigger mechanism can be useful.

'course, I'm a hardware guy and I'm stuck at the point of writing host software. Ugh! Maybe LabView will work: NI-VISA 3.0 supports USBTMC devices out of the box with no driver required (saves a lot of work) and runs on Macs and PCs. Maybe I'll have the device send over data and the host app will format it as VCD (Verilog Change Dump) files which can be read by GTKWave (which doesn't update in real time, so is less useful). Maybe I'll dive into more programming and come up with a neat digital display control (make it look like ModelSim).

Anyways, I totally agree: a 'scope is required. However, sometimes you need to see five or six or eight digital signals at the same time and a 'scope won't do that.

-a

List of 77 messages in thread
TopicAuthorDate
Parallel port Logic Analyser            01/01/70 00:00      
   Maybe I can help ...            01/01/70 00:00      
      Details            01/01/70 00:00      
         Well ... YES!            01/01/70 00:00      
            Oops!            01/01/70 00:00      
               another option            01/01/70 00:00      
               ideas            01/01/70 00:00      
               Try a DOS box            01/01/70 00:00      
                  When things are not going on my way..            01/01/70 00:00      
                     well            01/01/70 00:00      
                        Cost?            01/01/70 00:00      
                        cost            01/01/70 00:00      
                           Options            01/01/70 00:00      
                              ok well            01/01/70 00:00      
                              miniLA            01/01/70 00:00      
                                 Sorry!            01/01/70 00:00      
                                    I don't sell            01/01/70 00:00      
                                    If you want something you can build ...            01/01/70 00:00      
                                 MiniLA?            01/01/70 00:00      
                                    Buying, building and Writing..            01/01/70 00:00      
                                       You've got to decide ...            01/01/70 00:00      
                                       great start!            01/01/70 00:00      
                                          AVR!            01/01/70 00:00      
                                             realterm            01/01/70 00:00      
                                          But they're not reall fast enough            01/01/70 00:00      
                                             Cheat!            01/01/70 00:00      
                                                only if it gains you something            01/01/70 00:00      
                                                   to LA or not to LA            01/01/70 00:00      
                                                      I once made one            01/01/70 00:00      
                                                         cost of time... and price of learning...            01/01/70 00:00      
                                                            there is no such thing            01/01/70 00:00      
                                                               1MHz sampling            01/01/70 00:00      
                                                                  it's not that simple            01/01/70 00:00      
                                                                     architecture            01/01/70 00:00      
   Not sure how it compares            01/01/70 00:00      
      not very useful            01/01/70 00:00      
   there is no way in hades that a "paralle            01/01/70 00:00      
      how fast?            01/01/70 00:00      
      not so fast there, Erik            01/01/70 00:00      
         PCI LPT vs. onboard            01/01/70 00:00      
            Seems a mite slow!            01/01/70 00:00      
         yes, but part of the "software" is Windo            01/01/70 00:00      
            You're right, of course,            01/01/70 00:00      
               all good and well            01/01/70 00:00      
                  wotizit            01/01/70 00:00      
                  That's it, exactly!            01/01/70 00:00      
                     Won't work either            01/01/70 00:00      
                        will work            01/01/70 00:00      
                           yes, but not the way you think            01/01/70 00:00      
                              re FIFO use            01/01/70 00:00      
                              USB+FIFO: the simplest way            01/01/70 00:00      
                                 Have you considered this?            01/01/70 00:00      
                                    simplicity            01/01/70 00:00      
                                       yes, but it's not deterministic            01/01/70 00:00      
                                          YES YES YES            01/01/70 00:00      
                                             What do you mean "forget about..."            01/01/70 00:00      
                                                quick'n'dirty            01/01/70 00:00      
                                                   there are countries with low labor cost            01/01/70 00:00      
                                                      labour cost?            01/01/70 00:00      
                                                   Even if it's 768 TB, it's too small            01/01/70 00:00      
                        think about it some more            01/01/70 00:00      
                     10MHz?            01/01/70 00:00      
                        Not the USB, the FIFO!            01/01/70 00:00      
                           USB logic analyzer            01/01/70 00:00      
                              It's just a transfer mechanism            01/01/70 00:00      
            Zigbee timing            01/01/70 00:00      
               if a byte is 32 then a bit is 4 and you            01/01/70 00:00      
               arrrrrrrrrrrrgh and stuff,just use pci            01/01/70 00:00      
                  Yes, well, what did you expect?            01/01/70 00:00      
                     better mousetrap            01/01/70 00:00      
               I must have been more precise            01/01/70 00:00      
                  but WHEN?            01/01/70 00:00      
                     2420 interface details            01/01/70 00:00      
                        Focus on your current needs            01/01/70 00:00      
                           Thank you            01/01/70 00:00      
   reconstructed website            01/01/70 00:00      
   Update            01/01/70 00:00      

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