??? 03/08/06 17:21 Read: times |
#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 |