Oscilloscope

jbumatai

Hello,

What is a good spec bandwith for working with the SX Chips?

Thanks,
JBuma

Phil Pilgrim (PhiPi)

If it's within your budget, a 100MHz 'scope is likely to be adequate and is a fine complement to any test bench. Several years ago, when I began a project that used a 75MHz SX, I bought a fancy 300MHz storage 'scope. Tho' the storage features are certainly nice, I didn't really need the 300MHz bandwidth.

-Phil

jbumatai

Thanks for that quick reply. Now, I can narrow down my search.

Thanks again,
JBuma

RickB

If your need is for viewing logic levels instead of analog signals, this logic analyzer is a better choice. The hi speed interaction of a 75 MHx sx and external logic can result in glitches that even a 100 MHz scope won't see. Several of these have been purchased by members of the AVR Freaks Forum, and all are very pleased with them.

www.pctestinstruments.com/

I am not connected with Intronix nor do I own one of these...yet.

Rick

Phil Pilgrim (PhiPi)

I'd have to concur with Rick. If it's just logic monitoring you're after, something designed for that purpose might be better than an analog scope. One thing you need to check in the specs, though, is the sample depth. My Tek scope has a depth of only 10K samples per channel, and it's just not enough for most digital work. (I had buyer's remorse as soon as I realized that the equivalently-price Agilent analog+digital scopes could store 1M or more samples per channel.) I still need the scope's analog functions, though, so a digital-only logic analyzer wouldn't have been right for me.

-Phil

CarlC

I've been using one of those logic probes for SX troubleshooting work. I've been pretty happy with it. You can do some useful real time troubleshooting by programming your SX to output numbers on a group of four or more pins. Outputting states to indicate where you are in a program or even register values can be a pretty handy trick if you're trying to catch response to high speed input thats too fast for the usual debugging interface.

jbumatai

BTW: Thanks for the input. I am still researching options. Right now I am on a budget. So, how is the USB Osciloscope from Parallax for the SX28 Chip?

RickB

jbumatai
If you run the sx28 at 10 KHz it should be ok.

Rick

Capt. Quirk

BTW: Thanks for the input. I am still researching options. Right now I am on a budget. So, how is the USB Osciloscope from Parallax for the SX28 Chip?

10 Khz can't be right. Will the parallax USB Osciloscope work fine with the SX with a 4 to 20 Mhz resonator?
Also, are there any tasks·the SX performs, that the parallax USB Osciloscope can't do?

CCraig

He was kind of joking and kind of serious. The Parallax scope is slow. I think around 250 Khz. (correct me if I'm wrong.) So if your looking for clock pulses, your out. However, I'm usually poking around outputs which run much slower. I had a 20 Mhz scope that died so now I use the Parallax scope as my only scope. It's fine and gets the job done. I miss not being able to look at fast analog stuff, but I get by. For fast digital stuff and data streams, I use the LogiPort anayzer.

IMHO, the Parallax scope is just as good as some of the others which cost three for four times as much.

HTH, Chris

Capt. Quirk

Do you have an opinion on used Analog or Digital scopes I can buy on ebay vrs a computer based scope thats has features baised towards work with micro controlers?.

Also, is there any specific features to look for on a used analog or digital scope? I am looking for something that will allow me to use the SX·up to·50 Mhz (but·I use 4 mhz most of the time) and future Propeller chips.

Thanks

jb1311

I've had good luck with used test equipment on ebay. I recently bought an 1631D logic analyzer/oscilloscope and found it to be invaluable. It was less than $100 with shipping.

T'Saavik

ebay electronics gear is great!! Many companies unload great equipment because it costs to much to be calibrated or they switch "standards" and the older method of calibration isn't "legal" with the new standard.

That said i went the cheep/cheesy route of buying a usb scope a few years ago. The software for it is called "EasyScope" but the device has changed names several times. I think its called a "swordfish" or something fishy sounding like that.

Its worked great for me, but i've just started scratching the surface when it comes to looking at signals.

Update: Nope, its called the Stingray

Post Edited (T'Saavik) : 4/2/2007 4:40:25 PM GMT

Capt. Quirk

Does anybody have experince with one of these 34 CHANNEL LA1034 LOGICPORT LOGIC ANALYZER

RickB

@ Quirk

See my previous Intronics comment on this thread. Download the software to get a feel for it.

Rick

Capt. Quirk

Oops, Now I remember where I saw that link originally. This time though it was from a posting by KeithM (also an old post)

CCraig

Capt.,

I have one and it's great. However, it's not a scope. You really need both. (scope and analyzer). I'm very happy with the LogicPort only minor issues.

HTH, Chris