> I am looking for the cheapest oscilloscope I can get away with for
> simple PIC work (typ 4Mhz).  I don't anticpate using it for anything
> else.
> Can anyone tell me the basic specs I should look for (bandwidth,
> sampling rate, etc.)?

I would aim for 10x clock.  40MHz is a fairly low spec for a 'scope, 20MHz
will limit you at some point in future, or miss some nasty transient which
is messing up your circuit!  Sample rate isn't an issue if you are looking
for a cheap 'scope, a good cheap 'scope won't be a DSO.

Multiple channels are _very_ useful, most microcontroller fault-finding is
related to the relative timing of at least two pins, IME.  Get at least 2
channels, preferably with one external trigger input (it's like a very cut
down input channel, all it can do is trigger the trace) or 4 channels.
Moving probes around all the time is frustrating!

And if you want cheap, have a look on ebay.  Ignore anything less than
10-15 years old, and aim for Tektronix, HP, LeCroy etc.  When you see one
come up that is in your price range (or about 75% of your top price with an
hour or so to run!), put the make and model number into Google (or the
manufacturer's website, some still have manuals and specs online for old
models) and read what people think of it, don't forget to do a 'Groups'
search to see the usenet wisdom on it too.  If you're lucky, you might even
find a downloadable service manual.

I was wary about buying unseen from ebay, but after a couple of failed
auctions, I got myself a 60MHz Tek 453A for about 1/2 the price of a cheap
no-name single channel 'scope.  It works a treat, much _much_ better than
the 'cheap' brand scope it replaced.  Others experience seems to have been
the same, obviously YMMV!

> Would one of the simple USB PC Oscilloscopes be ok for PIC work?

Probably, but then you always need the PC display and have to do multiple
clicks and drags instead of just spinning a dial or pressing a switch.  You
can get an old scope in great condition for less than a new gadget, and it
may well outlive you...

Even though you _think_ you are doing digital work, only up to 4MHz, many
faults come down to analogue effects, and 1/2 of those are probably well
above 4MHz (brief sags or glitches on lines which the processor detects but
a 4MHz 'scope wouldn't really show up)

Nigel
--
Nigel Orr, Design Engineer                 nigel@axoninstruments.co.uk
Axon Instruments Ltd., Wardes Road,Inverurie,Aberdeenshire,UK,AB51 3TT
               Tel:+44 1467 622332 Fax:+44 1467 625235
                   http://www.axoninstruments.co.uk