NetNews Usenet Archive 1993 #1/NN_1993_1.iso/spool/comp/sys/next/hardware/3233

Text File | 1993-01-11 | 11.6 KB | 351 lines

Newsgroups: comp.sys.next.hardware
Path: sparky!uunet!wri!news
From: [e-mail] (Oleg Perelet)
Subject: Re: CD player -> NeXT DSP(Hook up a CD-Player to your NeXT)
Message-ID: <[e-mail]>
Sender: [e-mail]
Nntp-Posting-Host: merir.wri.com
Organization: Wolfram Research, Inc.
References: <[e-mail]>
Distribution: usa
Date: Mon, 11 Jan 1993 20:54:06 GMT
Lines: 337

In article <[e-mail]>
[e-mail] (Jonathan Hendry) writes:
> If anyone has the article which described how to hook a CD player
> to the DSP, could you please mail it to me? Or perhaps point me to
> where I might find it in the archives.
>
> Thanks!
>
>
Here it goes.

Thanx to Heubi Matthias.

BTW the same method works fine with NeXT-Sony CD drive.
Just look in:
SONY Semiconductor IC.
Data book, A/D, D/A Convertres.

Have fun.



From: [e-mail] (Michael Friedel)
Subject: Re: Hook up a CD-Player to your NeXT , A translation
Date: 12 Oct 91 08:12:08 GMT
References: <[e-mail]>
Sender: [e-mail]

In article <[e-mail]> [e-mail] (Heubi
Matthias)
writes:
>
> Hi there!
> I got an amazing bunch of mails regarding my article on how to
> hook up a Technics CD player to the NeXT.
>
> Following comes an ASCII version of the article I wrote for our
> magazine >>PowerKey<< of the NiCE - NeXT User Group.
> (This is the NeXT User Group here in Zuerich, Switzerland)
>
> The Graphics is not very PostScript, you should be able to figure
> out how it was meant, however.
>
> The article is in German. Knowing that translating from a foreign
> language to the mother tongue is far easier than the other way round,
> I'll leave the translation to one of you, nice net people)
> There's a short step by step summary in English at the end, however.
I'll try my best, although english isn't my mother tongue.
>
>
>
>
>
> So here it is (PowerKey, first issue):

Digital recording with the NeXT DSP
___________________________________

Who didn't have the dream of finally using the full sound capabilities of
his
or her NeXT computer? No more microphones, the music straight from there
CD-player into the NeXT, what wonderful sound that could be. No quality
loss !
Suddenly the NeXT would be a (very) expensive CD-player.

Those of you who are members that participated in the NiCE meeting on the
twelfth of August 1991 already know what I am talking about. One day I had
enough of this 'miserable' 8-bit sound. I finally wanted 16bit stereo. (It
is
pretty mundane to demo lousy, noisy , dull sounds and say "It could sound
a lot
better"

The Idea
---------
Digital sound data consists of bits and bytes. They should be second
nature to
the NeXT, just as graphics or text. Additionally the NeXT has a DSP-port;
a
serial interface to the DSP (Digital Signal Processor), a gateway to the
outside. Some clever guy had the idea to standardize digital sound data.
So id a CD-player internally processes the digital sound data serially,
and it
adheres to the standard, it should be possible that the two of them
(CD-player
and NeXT) could communicate.
Though of... implemented !

ATTENTION !!!
-------------
The following construction guide is ment for people who can tell which
side of
a soldering iron gets hot. Such operations usually void the warranty of
the
manufacturer. Make it clear to yourself that there is no way back, and
that you
really dont care..
[Left out a bunch of legalize, saying that the author isn't liable for
anything] It could be that the device explodes, is confiscated by the
FBI,......

As you couldn't resist to read on, you must be one of those hardware dare
devils that can't be stopped by anything.

The serial interface SSI
-------------------------
 The Synchronous Serial Interface of the DSP 5600, is an interface that is
designed to communicate with industry standard codecs (e.g. MC14550x).  It
could also be connected to a Analog to Digital Converter (DSP56ADC16).
(Such a
project is actually in the making, but as usual ... das Leben ist zu kurz,
und
Zeit ist zu teuer !!)

The SSI primarily consists of 3 pins.

        - SRD   SSI Receive Data
        - SCK   SSI Serial Clock
        - FSR   Receiver Frame Sync

Those make it possible to receive data (That is after all what we want).
To
transmit data, we need the following analog connections.

        - STD   SSI Transmit Data
        - SCK   SSI Serial Clock
        - FST   Transmitter Frame Sync


The pins of the DSP have the following names.

        - STD   SS Transmit Data        Pin 3
        - SRD   SSI Receive Data        Pin 2
        - SCK   SSI Serial Clock        Pin 1
        - SC0   Serial Control 0        Pin 14
        - SC1   Serial Control 1        Pin 13
        - SC2   Serial Control 2        Pin 12


The pinouts describe the connector on the back of the NeXT-cube or
station.
The signals FST, FSR as well as the separate clocks for transmitter and
receiver can be assigned by software to the different SCx pins. For our
purpose
we are going to use SC2 as combined transmitter/receiver frame sync.

The serial protocol
-------------------
              _   _   _   _   _   _   _   _   _   _   _   _   _   _
 Serial Clock | |_| |_| |_| |_| |_| |_| |_| |_| |_| |_| |_| |_| |_| |_|

                         ___________             ___________
 Frame Sync   ___________|           |___________|           |________

                         ___________ ___________ ___________
 Serial Data         ----X___________X___________X___________X----
                         ^^^^^^^^^^^
                         16 Bit serial data

As software protocol for this does not exist in my knowledge. The packets
contain the raw 16bit data, alternating between right and left channel.
The
frame sync enables us to determine which packet is for the right and which
for
the left channel.

We pry open the CD-player
---------------------------
This is a pretty futile attempt if the schematics for the device aren't
handy.
A call to your local TV/HIFI shop (how about Robert Waxman ?) or the
company
could prove to be fruitful. My component here is an older Technics (still)
without a digital output. In light of modern production and to save money,
most
CD-players probably use the same or very similar set of chips as the one
of
this Technics.
The exact procedure how to open this thing is described in the service
manual.

>From the schematic we can deduce that the digital signal processing EFM
decoder
MN6617 passes the data serially to the digital filter IC MN6618. It uses
the
following pins of the filter.
Just to annoy you Technics use SMD chips. So soldering on the three
connections
to the mentioned pins is instead of being a walk in  the park, a royal
pain in
the butt. (Some people might be drenched in sweat of fear).

Connecting the Wires
----------------------
We connect those in the following manner

IC-pinout, topview.

        -42-41-40- .......... -34-33----
      /                                |
    /                                  |
   |                                   |
   1                                  32
   |                                   |
   2                                  31
   |            MN6618F                |
   3                                  30
   |            DIGITAL FILTER         |
   .                                   .
   .                                   .
   |                                   |
   9                                  23
   |                                   |
   10                                 22
   |                                   |
   ------11-12-13-............-20-21----

   **** The IC IS NOT SYMMETRICAL, THAT MEANS NOT ****
   **** ALL SIDES HAVE THE SAME NUMBER OF PINS    ****

 NeXT DSP       -       CD-Player MN6618
 GND    (11)    -       GND     (everywhere)
 SCK    (1)     -       SFT     (30)
 SRD    (2)     -       SIN     (31)
 SC2    (12)    -       LRCK    (28)

Those of you who are the true dare devils probably will make a direct
connection between the CD and the IC. It is preferable to integrate a
buffer IC
like a  74241, or only a 7408. That way you wont soot you stereo to the
moon,if
something isn't connected correctly.

SOFTWARE
--------
As we have played by the rules as far as the protocol goes, we can safely
ignore the issue of software. The from NeXT supplied sndrecord will do the
job.
We just have to tell it to use the DSP.
hostname> sndrecord -d test.snd
Start the madness with a simple gentle tap on the return key and stop it
either by an energetic control-c or your storage space coming to a sudden
end.
The price you pay for such quality has its price; 10megs per minute.


> [e-mail]
> {mheubi,redaktor,powerkey}@nice.usergroup.ethz.ch
>
> _______________________________________________________________________

> AUTHOR
>   I'm an EE student from Switzerland (As you might have imagined,
>   by discovering all the mystackes :-) in the English part)
>   I can be reached through Email. (see above)
>
>   If you have any questions, please mail me.
>   I WILL *NOT* READ ANY NEWS IN THE NEXT FOUR WEEKS!
>   (I've got intermediate examination)
>
> COPYRIGHT
>   This article is copyrighted by NiCE - NeXT User Group. You may
>   translate it, and redistribute/reprint/duplicate it in any way
>   as long is it is for any non-profit purpose.
>   (It would be nice, if you would mention the source :-)
>
>   NiCE - NeXT User Group is the User Group for NeXT interested people
>   located near Zuerich, Switzerland. If you are interested in our Group,
>   contact me, or [e-mail] (who is the president).
>
> DISCLAIMER
>   NeXT,Technics,PostScript and probably CD are registered trademarks
>   of the corresponding companies.
>
>   I do *NOT* take any responsibility for any damage occured in any
direct
>   or indirect relation to this article, nor does so NiCE - NeXT User
Group.
>
>   You might well damage either your CD player and/or your computer
>   by applying anything written in this article. I can in no way grant
>   that anything described in this article works - (it does with my CD
>   player, however)
>
> #include <net_people/collection_of_std_disclaimers>
>
>
>
>
> ouffff.... that took rather long..
> Hope you liked it!
>
> Greetings, and have a NiCE day
>   Matthias
> --
> -----------------------------------------------------------------------
> Matthias Heubi       / NeXT / Atari ST / HP-48SX /        [e-mail]
> -----------------------------------------------------------------------

I have tried this with an old Sony of mine (D-7). I didn't have any
schematics,
non the less I got it to work. Unfortunately I dropped something into the
open
case after I got it working, shorting out a transistor for the motor
control
(at least that is what I think it is). That damn part is SMD, and I have
no
clue as to what its specifications are. So I guess one of these days I
will
have to hook up the oscilloscope and see if I can get it back into working
order. Or get myslef the schematics to this ancient baby.

Mike
--
/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
No user serviceable part inside. Warranty void if opened
modified or tampered with. No batteries included.
*
[e-mail]
[e-mail]
*
/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\

Non-standard disclaimer:
If anybody should try to commit suicide, willfully or not by attempting
the
above described operations, or destroy their dads stereo, make there NeXT
look
behave like an Amiga or any other related mishap, they cant hold me
responsible
for it.



--
Oleg Perelet
[e-mail]