Recommendation for DSP/Evaluation Board
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Recommendation for DSP/Evaluation Board
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Clay S. Turner
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Posted: Thu Dec 16, 2004 4:45 am    Post subject: Re: Recommendation for DSP/Evaluation Board Reply with quote
"Richard Dobson" <richarddobson@blueyonder.co.uk> wrote in message
news:%J0wd.275$Ar5.208@text.news.blueyonder.co.uk...
Quote:

Possibly one of the current Motorola 56~ development kits could be used as
the basis for an implementation; running nine sinewave oscillators should
be a doddle even for an original 56K! The Chameleon (see URL above) is
itself a very interesting product, and if you have the budget for it it
will do a great deal more than 9-partial additive synthesis. Use it with a
MIDI controller box for the pot controls, etc.

Here is an article I wrote a while back with sample code for the Moto 56002
doing an amplitude stablized oscillator. I even show how to stack them to
have multiple oscillators.

http://personal.atl.bellsouth.net/p/h/physics/1st_OSC_paper.pdf

Clay
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Jon Harris
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Posted: Thu Dec 16, 2004 4:45 am    Post subject: Re: Recommendation for DSP/Evaluation Board Reply with quote
"Richard Dobson" <richarddobson@blueyonder.co.uk> wrote in message
news:wI3wd.530$Ar5.68@text.news.blueyonder.co.uk...
Quote:
strato wrote:

..
5) I do have a budget. We are looking to build 10 units for under 20K.
I don't think this could be done on the outside for this low of a
budget. Most companies would prbably want more than 20K in just
engineering, and rightly so.

Do you actually require to build them? If not, the current price for a
Chameleon
box is about 700 Euros (SDK is free).
You could buy 10 Chameleons plus 10 simple MIDI controllers (so all you have
to
do is write the code), and have plenty left over from $20K. You might even get
a
discount for quantity!

Good idea, Richard. Just wondering, do you know of any suitable MIDI controller
off-hand (ideally would have 18 sliders/pots)?
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strato
Guest
Posted: Thu Dec 16, 2004 4:45 am    Post subject: Re: Recommendation for DSP/Evaluation Board Reply with quote
Jon,

Thanks! That clears things up. I don't necessarily need an input
signal, I may be able to generate the sine wave from data in a lookup
table (as suggested by Richard). I don't require a high quality
sinewave.

To all other posters,
thanks for all your valuable insight. Richard's suggestion for a
circuit similar to the Graphic Equalizer, is exactly what I'm looking
for, I will probably just mondernize it somewhat. I think of equal
concern is using a DSP with a good compiler and integrated code
development environment (preferrably C/C++), one that I can affort on a
University budget.

Strato
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Al Clark
Guest
Posted: Thu Dec 16, 2004 4:45 am    Post subject: Re: Recommendation for DSP/Evaluation Board Reply with quote
"strato" <strato79@comcast.net> wrote in news:1103157438.259103.141210
@z14g2000cwz.googlegroups.com:

Quote:
Jon,

Thanks! That clears things up. I don't necessarily need an input
signal, I may be able to generate the sine wave from data in a lookup
table (as suggested by Richard). I don't require a high quality
sinewave.

To all other posters,
thanks for all your valuable insight. Richard's suggestion for a
circuit similar to the Graphic Equalizer, is exactly what I'm looking
for, I will probably just mondernize it somewhat. I think of equal
concern is using a DSP with a good compiler and integrated code
development environment (preferrably C/C++), one that I can affort on a
University budget.

Strato



Strato,

This is a very easy application that can be done fairly inexpensively. If
you need 10 systems, I sure we can help you for a much lower figure than
you mentioned earlier today.

--
Al Clark
Danville Signal Processing, Inc.
--------------------------------------------------------------------
Purveyors of Fine DSP Hardware and other Cool Stuff
Available at http://www.danvillesignal.com
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Richard Dobson
Guest
Posted: Thu Dec 16, 2004 4:45 am    Post subject: Re: Recommendation for DSP/Evaluation Board Reply with quote
Jon Harris wrote:

...
Quote:


Good idea, Richard. Just wondering, do you know of any suitable MIDI controller
off-hand (ideally would have 18 sliders/pots)?


The cheapest, and possibly even the best in this case, is the new Behringer

"B-Control BCR2000":

http://www.behringer.com/BCR2000/index.cfm?lang=ENG

This has 32 rotary controls, 24 of which are high-resolution (14bit precision).
RRP about $200. It is reviewed in the current issue of Sound On Sound (Jan 2005
issue).

Being built down to a budget, there may be a question of robustness if subjected
to heavy use. It is unfortunate the requirement is for 18 controls, as there are
several similar products offering 16 sliders. The critical thing is to check the
specs to be sure they do offer high-resolution, as the Behringer expressly does.
MIDI supports two resolutions based on 7bit and 14bit encoding.

There is the Doepfer "Drehbank", which has a whopping 64 rotary encoders, which
seem all to be low-resolution; but with that many controls, one could program
one as "coarse" and another as "fine", etc.


Richard Dobson
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strato
Guest
Posted: Thu Dec 16, 2004 4:45 am    Post subject: Re: Recommendation for DSP/Evaluation Board Reply with quote
Thanks Clay,

Excellent paper. I now uderstand the idea of implementing multiple
oscillators to achieve the harmonic signals. I guess the final step
will be some sort of mixing alogrithm and level adjustment. After
reading everyone's replys it sounds like I should just design my own
PCB and not try to use demo/development boards. At a qty of 10 this
might be feasible.

Strato
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Jon Harris
Guest
Posted: Thu Dec 16, 2004 4:45 am    Post subject: Re: Recommendation for DSP/Evaluation Board Reply with quote
"Richard Dobson" <richarddobson@blueyonder.co.uk> wrote in message
news:h75wd.603$Ar5.514@text.news.blueyonder.co.uk...
Quote:
Jon Harris wrote:

Good idea, Richard. Just wondering, do you know of any suitable MIDI
controller
off-hand (ideally would have 18 sliders/pots)?


The cheapest, and possibly even the best in this case, is the new Behringer
"B-Control BCR2000":

http://www.behringer.com/BCR2000/index.cfm?lang=ENG

This has 32 rotary controls, 24 of which are high-resolution (14bit
precision).
RRP about $200. It is reviewed in the current issue of Sound On Sound (Jan
2005
issue).

Thanks. I'd seen that one once but forgotten about it.

Quote:
Being built down to a budget, there may be a question of robustness if
subjected
to heavy use. It is unfortunate the requirement is for 18 controls, as there
are
several similar products offering 16 sliders.

Yes, I thought the same thing.

Quote:
The critical thing is to check the
specs to be sure they do offer high-resolution, as the Behringer expressly
does.
MIDI supports two resolutions based on 7bit and 14bit encoding.

There is the Doepfer "Drehbank", which has a whopping 64 rotary encoders,
which
seem all to be low-resolution; but with that many controls, one could program
one as "coarse" and another as "fine", etc.

For the OP's application, even the low-resolution 7-bit controllers could
probably be enough for simple level and phase control, assuming appropriate
scaling was used.
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Richard Dobson
Guest
Posted: Thu Dec 16, 2004 4:45 am    Post subject: Re: Recommendation for DSP/Evaluation Board Reply with quote
strato wrote:

Quote:
Thanks Clay,

Excellent paper. I now uderstand the idea of implementing multiple
oscillators to achieve the harmonic signals. I guess the final step
will be some sort of mixing alogrithm and level adjustment. After
reading everyone's replys it sounds like I should just design my own
PCB and not try to use demo/development boards. At a qty of 10 this
might be feasible.

Strato


Note that most DSP chips these days are designed for machine placement, surface
mount, with ~lots~ of tiny pads ~very~ close together. If you don't have machine
placement and soldering facilities, that's somewhat finer soldering that I would
ever dare trying to do!

RIchard Dobson
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strato
Guest
Posted: Thu Dec 16, 2004 4:45 am    Post subject: Re: Recommendation for DSP/Evaluation Board Reply with quote
Yes, this is meant for student learning in general physics lab. The
MIDI idea is intrigiuing, do many DSPs support this interface directly?
Strato
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Jon Harris
Guest
Posted: Thu Dec 16, 2004 4:45 am    Post subject: Re: Recommendation for DSP/Evaluation Board Reply with quote
"strato" <strato79@comcast.net> wrote in message
news:1103160717.259646.98780@f14g2000cwb.googlegroups.com...
Quote:
Yes, this is meant for student learning in general physics lab. The
MIDI idea is intrigiuing, do many DSPs support this interface directly?
Strato

I don't know of any DSPs that support MIDI "directly". MIDI is just a
standardized protocol running on top of a simple 31.25 kbaud serial port (8-bit
characters). So anything with the appropriate connector and circuit (usually
involves an opto-isolator) and a UART can receive MIDI data. Processing it is
usually left up to software.
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strato
Guest
Posted: Thu Dec 16, 2004 4:45 am    Post subject: Re: Recommendation for DSP/Evaluation Board Reply with quote
Encoders are a great idea. I assume that I would need absolute encoders
or dedicated quadrature counters?

(Kidding aside) we considered the laptop option, we would use LabView
and talk to the sound card. The professor running the lab heavily
favors the standalone box option.

I was intending to do the design myself for professional development.
But if it can be done by an outside entity for less than the amout I
stated, I'd be happy to entertain any offers. I don't think I've
supplied enough specifications at this point, but I'd be happy to take
this discussion off line.

Strato
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strato
Guest
Posted: Thu Dec 16, 2004 4:45 am    Post subject: Re: Recommendation for DSP/Evaluation Board Reply with quote
Richard,

Good Point! At qty 10, I would probably want to assemble them myself. I
can solder 0.050 pitch but nothing closer. In the past I've designed
boards that use LCC that plugs into a socket with a PGA configuration.
Unfortunately, most design work for scientific instrumentation results
in very small final quantities.

Strato
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Al Clark
Guest
Posted: Thu Dec 16, 2004 4:45 am    Post subject: Re: Recommendation for DSP/Evaluation Board Reply with quote
"strato" <strato79@comcast.net> wrote in news:1103161846.642955.171890
@f14g2000cwb.googlegroups.com:

Quote:
Encoders are a great idea. I assume that I would need absolute encoders
or dedicated quadrature counters?

(Kidding aside) we considered the laptop option, we would use LabView
and talk to the sound card. The professor running the lab heavily
favors the standalone box option.

I was intending to do the design myself for professional development.
But if it can be done by an outside entity for less than the amout I
stated, I'd be happy to entertain any offers. I don't think I've
supplied enough specifications at this point, but I'd be happy to take
this discussion off line.

Strato


You can probably interface a midi interface directly to the RS-232 port on
the dspstak 21262sx and you can absolutely emulate an RS-232 using the DAI.



--
Al Clark
Danville Signal Processing, Inc.
--------------------------------------------------------------------
Purveyors of Fine DSP Hardware and other Cool Stuff
Available at http://www.danvillesignal.com
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strato
Guest
Posted: Thu Dec 16, 2004 4:45 am    Post subject: Re: Recommendation for DSP/Evaluation Board Reply with quote
I guess I should do more research before asking, I didn't know it was a
realatively simple interface. I've implemented similar protocols on
micro-controllers such as SPI, I2C etc. In the past by just toggling
some I/O pins on the micro via a software algorithm.

Buying these MIDI boxes of the shelf is a very appealing solution.
Strato
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Jon Harris
Guest
Posted: Thu Dec 16, 2004 4:45 am    Post subject: Re: Recommendation for DSP/Evaluation Board Reply with quote
"strato" <strato79@comcast.net> wrote in message
news:1103161846.642955.171890@f14g2000cwb.googlegroups.com...
Quote:
Encoders are a great idea. I assume that I would need absolute encoders
or dedicated quadrature counters?

I was thinking of the quadrature kind.

Quote:
(Kidding aside) we considered the laptop option, we would use LabView
and talk to the sound card. The professor running the lab heavily
favors the standalone box option.

I was intending to do the design myself for professional development.
But if it can be done by an outside entity for less than the amout I
stated, I'd be happy to entertain any offers. I don't think I've
supplied enough specifications at this point, but I'd be happy to take
this discussion off line.

I'm not the one for the job, but someone else in this group might be. But if
you have the time and inclination to do it yourself, I would go for it! Of
course, ask questions when you are stumped. You will learn a lot and have the
satisfaction of knowing you did it yourself. Plus, you will be better equipped
to fix the units when the students break them! :-)
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