delorie.com/archives/browse.cgi   search  
Mail Archives: djgpp/2000/08/26/13:18:18

From: "Thorsten Erdmann" <thorsten DOT erdmann AT gmx DOT de>
Newsgroups: comp.os.msdos.djgpp
Subject: More CD ROM problems
Date: Fri, 25 Aug 2000 19:40:36 +0200
Organization: AddCom AG
Lines: 34
Message-ID: <8o6c75$6sq$1@riker.addcom.de>
NNTP-Posting-Host: h-213.61.84.78.host.de.colt.net
X-Trace: riker.addcom.de 967226405 7066 213.61.84.78 (25 Aug 2000 18:00:05 GMT)
X-Complaints-To: news AT news DOT addcom DOT de
NNTP-Posting-Date: 25 Aug 2000 18:00:05 GMT
X-Priority: 3
X-MSMail-Priority: Normal
X-Newsreader: Microsoft Outlook Express 5.00.2014.211
X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2014.211
To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp
Reply-To: djgpp AT delorie DOT com

Hi,

I want to built a standalone MP3 player which should be able to play from
CD.
For start I will use a PC under DOS/DJGPP, but later it will become a small
68000
system. So I need to program the CDROM directly on hardware level (MSCDEX
doesn't seem to recognize CD changes anyway).

So I tried Hale's ATA driver and it works fine - mostly. First but minor
problem
is the ATAPI Identify command 0x81. As I understand it is a ATA-like
command. But I get no response from the drive. Also the ATA/IDE-Identify
command fails. On harddrives it works.

Now the main problem. How can I determine if a media is in the drive and if
a media change occurred. I want to display an open or closed CD-drive icon
on the player's display. So I need a command which requests the tray status
and the media changed status whithout interferring with a currently running
audio play command.

What I find out is, that in case of media change the next command to the
drive returns an error condition. But I don't think that's the right way to
detect a media change. I think the Mode Sense Command is the right way, but
I don't understand the description of that command in the ATAPI
documentation.

Maybe someone has a code snippet of such a routine. Hope you can help me.

Thank you
Thorsten



- Raw text -


  webmaster     delorie software   privacy  
  Copyright © 2019   by DJ Delorie     Updated Jul 2019