zajmavý PC oscík

Snail Instruments snail@iol.cz
Pátek Červenec 9 10:22:58 CEST 2004


Jestli muzu malou inzerci - je novy BS50 komunikujici a napajeny pres USB. Chystam se ho zaradit do sortimentu vedle BS220. Pridavam par poznamek z konference Bitscope.

J. Hanzal

Brian Schmalz wrote:
 > OK Bruce. You really have pulled a nice one out of your 
hat. The
 > Pocket Analyzer looks SO COOL! I can't wait to get mine. 
(anybody need
 > $295 of freelance embedded systems engineering done?)

Thanks :-)

 > Does is use the exact same schematic as the earlier units 
(like
 > 200/300) but with surface mount parts to make it small?

The schematic is very similar but not exactly the same; for
one, the use of one SRAM for both analog ang logic data.
Another is the addition of an optional x10 analog gain stage
in the BNC input path (which is how we get down to 200
uV/Div in BS50, aka pocket analyzer). BS50 also has only one
BNC input path but retains the 2 POD analog inputs (a total
of 3 analog inputs).

 > Does it use the same processor/FPGA or have you upgraded 
them?

The PIC is the same. The PLD is a newer but similarly
featured Lattice chip.

 > Is the processor programmable across USB (for software 
upgrades)?

PIC firmware is not upgradeable without chip replacement.
That said, we don't anticipate the need for an upgrade as it
uses the now very stable BS30x design and being implemented
as a programmable virtual machine feature upgrades are now
implemented entirely as software upgrades on the PC.

 > Do you use the FTDI serial or parallel chip for the USB 
access, or do
 > you use something different?

We use the FT245BM communicating directly with the PIC via
the bus. It's capable of faster communications speed than
the BS300 design.

 > What are the abilities of the DAC? (voltage ranges, 
selectable
 > playback rates, etc.)

The AWG is very similar to the BS300 design. It can replay
PC uploaded waveform data at sample rates up to 10 MS/s and
down to a few kHz. With 32k of sample buffer available you
can synthesize waveforms from sub-Hz frequencies to a few
MHz. The output control offers amplitude and offset controls
given you a maximum Vp-p of about 7V with (5V positive to
-2V negative).

BS50 also offers the ability to output the waveform as a
logic pattern on the logic pins concurrently.

 > Is the housing solid metal like the previous units? (i.e. 
is it heavy?
 > )

It is an sleeve design like all other BitScopes ie, it is
solid, *but* it's made from a lighter grade aluminium so it
weighs just 6.5 oz. (=180g)

 > How much current does the unit draw from the USB line?

About 300 mA with nothing drawing power from the POD. Most
USB ports can supply sufficient power but for unpowered HUBs
or older notebooks that might have trouble, external power
can be used. If you draw power from the POD for your own
circuits you will need to budget for this additional current
from your PC's USB port, or use a 9V external DC adaptor.

 > Are there going to be any additional capibilities in this 
unit? (i.e.
 > more trigger modes, different ADCs, different software 
modes or
 > registers, etc.)

There are a few differences (eg, pattern generator, logic
only capture, S/W selectable AC/DC and 50 ohm termination),
but none significantly change the way the software works
compared to a BS300.

 > Is it going to be in a reduced-cost kit form too?

No. We're looking at a simpler thru-hole design for a new
kit design down the road. SMT designs are not amenable to
kitting and home construction and our BS300 kits, while very
popular have proven to be too costly (compared to the built
units) to produce now. Some thru-hole components are also
becoming as scarce as hen's teeth !

 > Thanks for continuing development - the Pocket Analyzer 
is just what
 > we need.

Thanks for the positive feedback. The website will be
updated during July with more information about BS50 as well
as a new (as yet unreleased) model called BS310.

Stay tuned :-)




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