losttoy2000@yahoo.co.uk (Siddhartha Jain) wrote in
news:2c39af62.0406082249.4d53d6af@posting.google.com: 

>> >> Then why do Stand-alone MP3-CD player projects like the ones I
>> >> mentioned below use a IDE controller (Intel 8255A)?
>> > 
>> > IIRC an 8255 is a fairly simple parallel port adapter.
>> 
>> I was thinking the same thing. I never thought of the venerable 8255
>> I/O expander as an IDE controller. I mean try an command the 8255 to
>> READ DMA and see what it does. :-)

> Well, someone seems to have done it. Check this:
> http://www.pjrc.com/tech/8051/ide/wesley.html
> 
>:)
 
No, they didn't. This example is PIO. UDMA transfers cannot be
accomplished with an 8255 acting as the "disk controller". The IDE
interface in PIO mode is quite similar to a plain old chip selected device
like an SRAM or FLASH chip so, yes, you can do that with an 8255. Of
course if you just use a chip with more I/Os then you wouldn't even need
the 8255. 

-- 
- Mark ->
--

Well, someone seems to have done it. Check this:
http://www.pjrc.com/tech/8051/ide/wesley.html

:)

Siddhartha

"Mark A. Odell" <odellmark@hotmail.com> wrote in message news:<Xns95028491E7031CopyrightMarkOdell@130.133.1.4>...
> CBFalconer <cbfalconer@yahoo.com> wrote in
> news:40C5E443.5EEC4FCF@yahoo.com: 
> 
> >> Then why do Stand-alone MP3-CD player projects like the ones I
> >> mentioned below use a IDE controller (Intel 8255A)?
> > 
> > IIRC an 8255 is a fairly simple parallel port adapter.
> 
> I was thinking the same thing. I never thought of the venerable 8255 I/O
> expander as an IDE controller. I mean try an command the 8255 to READ DMA
> and see what it does. :-)

Siddhartha Jain wrote:
> So you are saying that if I used the ACD player drive then I don't
> need the ATAPI controller? How do I read filenames for display then?

ATAPI has nothing whatever to do with the *structure* of the data,
it's an electrical interface (and protocol) to read the raw data.
It only exists to funnel a SCSI-like command set over IDE hardware.
Neither is useful to a stand-alone player.

> Yep, I know but the point was that if you used any other format other
> than ISO9660, most MP3-CD players won't read it. Now that would not be
> the case if the Mp3-CD players just took the raw stream from the lens
> and fed it to the MP3 decoder. Right?

Wrong. They take parts of the raw disk stream from here and there, and
interpret the results as an ISO9660 filesystem which tells them where
to find files etc. Then they "open" those files by reading the mp3
tag from the end, which gives them track/artist/album/etc to display.
When you select "play", they read the section of the disk's raw data
which corresponds to the audio content for the selected file, and feed
it to the decoder. None of this needs IDE/ATAPI, just the ability to
seek and read raw data.

> Other than MP3-CD players, look at the USB Flash MP3 players. Now
> these players (~US$50) can read FAT32 filesystem on the flash drive.

Yes. But that doesn't require ATAPI either, of course.

> Ofcourse, the best thing to do would be to open up a Mp3-CD or
> Flash-Mp3 player and look at the insides. If anyone already has, could
> you please share a few pics and specs?

You'll find a custom controller chip which probably contains all the
iso9660 stuff lumped in with the drive controller and possibly even the
display driver.

> Because the stand alone player projects do use an IDE/ATAPI drive, as 
> that's the only economical way of buying a CD drive.

So you are saying that if I used the ACD player drive then I don't
need the ATAPI controller? How do I read filenames for display then?
 
> And the CD player is designed to read the ISO9660 format because that is 
> the standard format that is used by everyone's CD burners.

Yep, I know but the point was that if you used any other format other
than ISO9660, most MP3-CD players won't read it. Now that would not be
the case if the Mp3-CD players just took the raw stream from the lens
and fed it to the MP3 decoder. Right?

I looked at the specs of a MP3 decoder chip. It said that the chip can
take a raw stream and ignore the garbage. So what you say must be
right but then the same  question. How do they read filenames and
browse folders?

Other than MP3-CD players, look at the USB Flash MP3 players. Now
these players (~US$50) can read FAT32 filesystem on the flash drive.
So they must have an intelligent controller that does more than just
pump raw streams to the MP3 decoder.

Ofcourse, the best thing to do would be to open up a Mp3-CD or
Flash-Mp3 player and look at the insides. If anyone already has, could
you please share a few pics and specs? Or else, I will buy one of
these and do that (Ehh, US$25 is not that small a amount here :) )

Thanks for your patience Tim!

Cheers,

Siddhartha

CBFalconer <cbfalconer@yahoo.com> wrote in
news:40C5E443.5EEC4FCF@yahoo.com: 

>> Then why do Stand-alone MP3-CD player projects like the ones I
>> mentioned below use a IDE controller (Intel 8255A)?
> 
> IIRC an 8255 is a fairly simple parallel port adapter.

I was thinking the same thing. I never thought of the venerable 8255 I/O
expander as an IDE controller. I mean try an command the 8255 to READ DMA
and see what it does. :-)

-- 
- Mark ->
--

Siddhartha Jain wrote:
> 
> Then why do Stand-alone MP3-CD player projects like the ones I
> mentioned below use a IDE controller (Intel 8255A)?

IIRC an 8255 is a fairly simple parallel port adapter.

-- 
A: Because it fouls the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing on usenet and in e-mail?

In article <2c39af62.0406080602.75dbce0e@posting.google.com>, Siddhartha 
Jain <losttoy2000@yahoo.co.uk> writes
>Then why do Stand-alone MP3-CD player projects like the ones I
>mentioned below use a IDE controller (Intel 8255A)?
>And if no controller is involved except for motor control then why do
>manufacturers require that you burn the Mp3 CD in ISO9660 format?
>

Because the stand alone player projects do use an IDE/ATAPI drive, as 
that's the only economical way of buying a CD drive.

And the CD player is designed to read the ISO9660 format because that is 
the standard format that is used by everyone's CD burners.
-- 
Tim Mitchell

Then why do Stand-alone MP3-CD player projects like the ones I
mentioned below use a IDE controller (Intel 8255A)?
And if no controller is involved except for motor control then why do
manufacturers require that you burn the Mp3 CD in ISO9660 format?

Just curious.



Tim Mitchell <timng@sabretechnology.co.uk> wrote in message news:<h9kRmwOkbZxAFA0V@tega.co.uk>...
> In article <2c39af62.0406071401.1fea8ed7@posting.google.com>, Siddhartha 
> Jain <losttoy2000@yahoo.co.uk> writes
> >Thanks Vadim. But I am more interested in modding a MP3-CD player to
> >accept HDD. Why?? A MP3-CD player costs ~US$25. In this amount, you
> >get a MP3 decoder, DAC, LCD Display, IDE/ATAPI controller(?). So if I
> >could add a ~US$50 2.5 inch HDD to it then this would be the cheapest
> >HDD-MP3 player by far!!
> >
> >I opened up my older Audio CD player (Sony) and found a legacy 14-pin
> >cd drive controller. Need to procure a MP3-CD player and open that up.
> >Assuming that a MP3-CD player has a IDE/ATAPI controller, any clue
> >what would it take to emulate ATAPI (by a ATA disk)? I see two
> >problems:
> >1. ATA to ATAPI bridging or ATAPI emulation in hardware.
> >2. The controller on the MP3 CD player might be hard-coded to read
> >addresses covering only 650MB (CD size)?
> 
> Standalone MP3 CD players do not get involved in IDE or ATAPI. They 
> handle the raw data from the disc pickup directly. It is not possible to 
> do what you are suggesting.

The Fujitel MP3/VCD/ACD player retails for Rs.1250 (Approx US$25) in
India.

The Mp3 CDs are burned in the ISO9660 format. If a CD-Mp3 player does
not have a IDE/ATAPI controller, how else would it read the CD? And
all the open Mp3-CD player designs I came across on the net include a
IDE/ATAPI controller. http://home.hetnet.nl/~victorvanacht/ and
http://www.pjrc.com/tech/8051/ide/wesley.html

Btw, I opened an older (4 year) Sony ACD player and found that it has
a Sony CXA2542AQ controller chip for the cd-drive with a 14-pin
connector. Now the 14-pin is the legacy cd connector. Another old
panasonic VCD/ACD player had a 16-pin connector. Looks proprietary.
Looking for a Mp3-cd player to dissect :)

Cheers,

Siddhartha


Clifford Heath <cjh-nospam@nospaManagesoft.com> wrote in message news:<1086670083.912622@excalibur.osa.com.au>...
> Siddhartha Jain wrote:
> > Assuming that a MP3-CD player has a IDE/ATAPI controller
> 
> That seems highly unlikely, especially for $25.
> 
> For your other question, "mkisofs" in every Linux distribution
> can make iso9660 images in any size.

In article <2c39af62.0406071401.1fea8ed7@posting.google.com>, Siddhartha 
Jain <losttoy2000@yahoo.co.uk> writes
>Thanks Vadim. But I am more interested in modding a MP3-CD player to
>accept HDD. Why?? A MP3-CD player costs ~US$25. In this amount, you
>get a MP3 decoder, DAC, LCD Display, IDE/ATAPI controller(?). So if I
>could add a ~US$50 2.5 inch HDD to it then this would be the cheapest
>HDD-MP3 player by far!!
>
>I opened up my older Audio CD player (Sony) and found a legacy 14-pin
>cd drive controller. Need to procure a MP3-CD player and open that up.
>Assuming that a MP3-CD player has a IDE/ATAPI controller, any clue
>what would it take to emulate ATAPI (by a ATA disk)? I see two
>problems:
>1. ATA to ATAPI bridging or ATAPI emulation in hardware.
>2. The controller on the MP3 CD player might be hard-coded to read
>addresses covering only 650MB (CD size)?

Standalone MP3 CD players do not get involved in IDE or ATAPI. They 
handle the raw data from the disc pickup directly. It is not possible to 
do what you are suggesting.

-- 
Tim Mitchell