Re: Logic Analyzer Vs. Oscilloscope

"Michael" <nospam@xxxxxxx> wrote in message
news:447CA206.B89D1FCD@xxxxxxxxxx
Himanshu Chauhan wrote:
(snip)
Other folks pretty well outlined some of the differences between the
two, so I
will not add to that.

If you putter with digital stuff very much you will probably want a
logic
analyzer at some point. If you have the money to purchase a commercial
unit,
fine. If not, consider building one after you've learned more about
micros. I

Well Michael, Ain't it a problem of Chicken or Egg. To build a logic
analyzer using
a uC at home, don't we need LA? Can you please throw a light on this?

It could be. Might not be. Depends on several things, e.g. how
extensive/expansive your design is, how *good* your design and proto are
when
you power up the proto for the first time. Also how many wiring mistakes
you
make and what kind of mistakes they are. Stuff like that.

The "analyzer" I described last time is very simple: just 1 channel. The
uC
simply timestamps each high/low transition of that channel and saves to
SRAM. I
made three wiring errors, and finding them using an ohmmeter cost me about
4
hours. Having a proper LA would not have cut any time off that. What
*would*
have made things a whole lot easier is using several colors of wire when
building, instead of just the YELLOW I had!

I'll second all of that. A logic analyser is useful in very specific
circumstances - where one needs to watch a lot of logic states at the same
time. This is usually a hardware debugging phase... and if you're careful
with the design, you might never need it. (I think I've used one once in 30
years.)

A decent 'scope, however, is a very handy thingy indeed. I like to probe
around new boards just to ensure that there's nothing lurking that could
bite me. The 'scope needs to have decent bandwidth; there's no point looking
for e.g. good rise and fall times if the 'scope is the limiting factor. For
the kind of thing I do, I'd say that a 60-100Mhz 'scope is the absolute
minimum that's worth having - anything slower is fine for audio, but not too
much help with modern digital. Needn't cost an arm and a leg - I bought mine
second-hand for $small_sum.

Oh - and a *storage* 'scope is a very, very, very useful thingy.

HTH,

Steve
http://www.fivetrees.com


.

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