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=DSP Information=
 +
<pre>
 +
Subject: AV DSP Mini-FAQ v 1.01
 +
From: [email protected] (Benjamin Denckla)
 +
Date: 7 Dec 1993 17:43:17 GMT
 +
 +
This document contains information relevant to the AV Macs,
 +
especially in relation to the use and programming of their DSP chip.  It
 +
is the product of my own experience and many helpful responses I
 +
have received to posts I have made.  I have taken slight liberties in
 +
editing responses, so what you see below are not always the exact words
 +
of the contributors to the FAQ.  It is structured in the typical FAQ
 +
format of question and answer with the questions listed at the
 +
beginning.  Please write me with any additions to or comments about this
 +
document.
 +
 +
Ben Denckla
 +
Manager
 +
Harvard University Electronic Music Studio
 +
 +
 +
1. Are modem/fax software and the GeoPort telecom adapter included?
 +
2. Does audio output from the CD have an extra stage of A/D & D/A?
 +
3. Is there an included utility which allows digital recording of part
 +
of an audio CD to an AIFF file?
 +
4. Is there an included utility which will allow me to play/record 16-
 +
bit, 44.1KHz stereo AIFF files?
 +
5. Is there any digital audio software available for the 660AV?
 +
6. Is there any digital audio interfacing hardware available? (AES/EBU
 +
<--> DAV  or  AES/EBU <--> GeoPort)
 +
7. What is needed to do DSP programming?
 +
8. Where can I get example code for programs that use the AV's DSP?
 +
9. Where can I get information about the DSP chip?
 +
10. BugLite only supports 32-bit floating point data.  Do I really want
 +
to use this data type?
 +
11. Can I use Think C to write the Macintosh part of DSP applications?
 +
12. What happens to DSP modules I have written when the hardware
 +
platform changes (to PowerPC, for instance)?
 +
 +
 +
 +
.c.1. Are modem/fax software and the GeoPort telecom adapter included?
 +
 +
The Geoport adapter must be bought separately for about $125. The
 +
adapter comes with the modem driver software and a complete, user-level
 +
fax software package.  So you still need to own a separate modem
 +
communications program.  Contrary to what some documentation says, you
 +
can do 14.4Kbaud, not just 9600 baud, with the modem.
 +
As an aside, I would like to point out that though the AV does
 +
speech generation and recognition right out of the box, it can't do
 +
modem/fax out of the box.  Frankly I cannot believe that the number of
 +
users needing speech functions even approaches the number who need
 +
modem/fax.  A clear case of "Gee-whiz! Bells & whistles! Screw the
 +
user!" marketing.  Not that the $125 for the GeoPort even compares the
 +
the $995 for the ARTA toolkit (see below).
 +
 +
 +
.c.2. Does audio output from the CD have an extra stage of A/D & D/A?
 +
 +
Yes.  Evidence of this appears on p. 39 of Apple Developer Note
 +
#5, where the L & R outputs of the CD enter a block labelled "analog
 +
front end" before entering the Singer block.
 +
John Turpin <[email protected]> confirms this and notes that the
 +
digital audio output from the CD is not compatible with the singer
 +
serial data bus.
 +
 +
 +
.c.3. Is there an included utility which allows digital recording of
 +
part of an audio CD to an AIFF file?
 +
 +
No.  In order to to this, you need to open a QuickTime-
 +
aware application and select the audio "file" from the mounted
 +
CD using the File Open menu item.  You'll then get a dialog
 +
asking for conversion confirmation.  Then you will have a
 +
QuickTime movie with 16-bit audio which still needs to be
 +
converted to an AIFF file.  I am not sure if such a utility
 +
exists, but it seems probable that it does.
 +
 +  +
contributed to the answer of this question.
 +
 +
 +
.c.4. Is there an included utility which will allow me to play/record
 +
16-bit, 44.1KHz stereo AIFF files?
 +
 +
No.  The bundled version of FusionRecorder does allow you to
 +
record this kind of audio into QuickTime movies, though.
 +
 +
 +
.c.5. Is there any digital audio software available for the 660AV?
 +
 +
s[email protected] (Doug Slansky) replies:
 +
Contact OSC (800-343-3325) regarding Deck II, a sound editing
 +
program being upgraded specifically to use the 3210 in the AVs.  See
 +
MacWeek (10/4/93), page 24 for details.
 +
 +
.c.6. Is there any digital audio interfacing hardware available?
 +
(AES/EBU <--> DAV  or  AES/EBU <--> GeoPort)
 +
 +
Open question.
 +
 +
 +
.c.7. What is needed to do DSP programming?
 +
 +
[email protected] (george.t.warner) replies:
 +
Tools for DSP development under the Apple Real Time Architecture 
 +
(ARTA) on AV Macs are available for $995 from:
 +
 +
Spectral Innovations
 +
1885 Lundy Avenue, Suite 208
 +
San Jose, CA  95131
 +
408/955-0366
 +  +
 +
You will need MPW to use these tools. The tools include the AT&T
 +
DSP3210 assembler, linker/loader, simulator, Macsbug D Commands, Apple
 +
Snoopy browser/debugger, and Apple BugLite graphical DSP module
 +
installer. It does not include the C Compiler but as you may have
 +
already read, the compiler is not very good.  Fortunately, DSP3210
 +
assembly programming (unlike other DSPs) is very C-like, so getting up
 +
to speed is not too difficult.  The main part is getting used to the
 +
latencies involved with the pipelined architecture.
 +
Additionally, the AT&T Application Library includes many (about
 +
100?) useful DSP algorithms (FFTs, FIR and IIR filters) with complete
 +
source code.  It should sell for about $100.
 +
 +
[email protected] (Walter Horat) replies:
 +
Apple got the 3210 tools from AT&T, which were written to use VCOS
 +
(AT&Ts 3210 realtime O/S).  Apple modified the tools somewhat for use on
 +
the Mac, and began shipping them to developers.  When Apple realized
 +
that it might cost money to actually *support* the tools, they foisted
 +
the tools off on a company called Spectral Innovations (actually not a
 +
bad choice since Spectral has been doing programming for AT&T DSPs for
 +
over five years).
 +
BTW, the 'C' compiler is a complete piece of shit.  It produces
 +
some of the worst code I have ever seen (trying to do a matrix multiply
 +
in 3210 'C' ran 5 times slower than the host 68k on a Quadra 700 -
 +
rewriting the same in assembler ran 7-8 times *faster*).  If you do any
 +
serious 3210 programming, you will need to learn 3210 assembler.
 +
 +
Ben Denckla replies:
 +
I now own the ARTA toolkit and have a few comments about it. 
 +
First of all, a few picky remarks about the documentation.  It comes in
 +
two parts:
 +
A. A big stack of 3-hole punched looseleaf paper, containing about
 +
10 different sections, only two of which are separated from each other
 +
in any manner (you have to hunt through and separate out the documents). 
 +
No overall table of contents, not even an overall list of contents.
 +
B. A spiral bound, bad photocopy of the AT&T DSP3210 manual.  The
 +
photocopy is blurry and has at least one page out of order (the first
 +
page of the table of contents, actually).  It's unclear why they don't
 +
just get some from AT&T since AT&T is willing to send out the real thing
 +
for free (see below).
 +
There are only 3 tiny examples of realtime DSP modules included,
 +
and I believe only 1 timeshare task example exists.  The examples are
 +
not well-documented.
 +
The cost is amazingly prohibitive.  If you look at the price of
 +
APDA developer's toolkits for things like Telephone Manager, Sound
 +
Manager, or MIDI Manager, they are less than one tenth the price ($75,
 +
$50, and $35 respectively).  I thought my 660AV was going to be a real
 +
steal for $1820 + whatever development tools were needed.  Well I had no
 +
clue that that "whatever" would be $995, more than half of the price of
 +
the computer itself.  So the 660AV makes a lot of sense: it does speech
 +
generation and recognition (two capabilites that are really only needed
 +
for people with disabilities) right out of the box, but you have to pay
 +
$995 to actually be able to program the thing.  Does the price of such
 +
DSP development software reflect the fact that DSP programming is an
 +
esoteric activity, or does it _cause_ DSP programming to remain
 +
esoteric?  I thought the 660AV was a revolution in bringing DSP
 +
programming onto the personal desktop.  I was wrong, because the cost of
 +
the development software shattered the illusion of the bargain.
 +
 +
 +
.c.8. Where can I get example code for programs that use the AV's DSP?
 +
 +
See question #7 for description of DSP module examples that come
 +
with the ARTA toolkit.
 +
 +
Author:      George Warner <[email protected]>
 +
Name:        ARTAbrot 1.1
 +
Description:  Mandelbrot program
 +
Source Code:  Mac & DSP
 +
Location:    sumex-aim.stanford.edu
 +
              archive.umich.edu
 +
              AmericaOnLine
 +
              AppleLink (Developer Code Submissions area)
 +
 +
Author:      Malcolm Slaney <[email protected]>:
 +
Name:        VUMeters
 +
Description:  simulates analog VU meters
 +
Source Code:  Mac (Think C) & DSP
 +
Location:    ears.atg.apple.com
 +
 +
 +
.c.9. Where can I get information about the DSP chip?
 +
 +
Call AT&T Microelectronics (1-800-372-2447) and ask for the "AT&T
 +
DSP3210 Digital Signal Processor Information Manual".  They sent it out
 +
to me quickly & for free.
 +
 +
 +
.c.10. BugLite only supports 32-bit floating point data.  Do I really
 +
want to use this data type?
 +
 +
[email protected] (Walter Horat) replies:
 +
I used to think the same way before programming on the 3210 (I
 +
don't need floats, so I'll just program in integer arithmetic).  Once
 +
you get into the architecture of the chip and the instruction set, you
 +
realize that it really was designed *only* to manipulate floating point
 +
data types.  The integer operations which the chip supports are not very
 +
robust, for instance there is no integer multiply.  But, you can
 +
effectively convert a 8 or 16 bit integer (in signed, unsigned, u-law or
 +
a-law format) to a dsp-floating point number in a single instruction
 +
cycle.  The reverse conversion is just as fast.  And you can convert
 +
from dsp/ieee and ieee/dsp format in a single instruction (an
 +
instruction takes four cycles to process, but the 3210 has a four-stage
 +
pipeline, so instructions effectively complete in 1 cycle)
 +
 +
 +
.c.11. Can I use Think C to write the Macintosh part of DSP
 +
applications?
 +
 +
Malcolm Slaney <[email protected]> replies:
 +
YES!  The VUMeters application [see question #8] was done this
 +
way. Only the DSP code needs to be compiled under MPW.  The ARTA Toolkit
 +
does include a good  DSP simulator which definitely makes code
 +
development easier.
 +
 +
 +
.c.12. What happens to DSP modules I have written when the hardware
 +
platform changes (to PowerPC, for instance)?
 +
 +
[email protected] (george.t.warner) replies:
 +
The DSP3210 will not go away when the PowerPCs come out.  While
 +
Apple has not yet announced what their plans are, I can say that it is
 +
very likely that third parties will make plug-in DSP3210 boards for
 +
PowerPCs not equipped with a DSP.
 +
</pre>
    
=See Also=
 
=See Also=