Subject: Controlling a CDROM with a PIC

There is a "play CD" command in the command set that plays the whole
CD to completion.  This is what is used when you set the CD to play
in your system and then jump out of the CD play program to a user
application (and it still plays on).  Once the command is sent you
can do anything and it continues on.  So you could even do this with
a couple dollars worth of TTL logic.  If you want more specific
control of the player then, yes, it gets more complicated - but
this is very simple to do - load the command and strobe it in.  The
commands are documented in the Atapi spec and maybe the enhanced IDE
spec.  These should be on a web site somewhere, like our WDC.com,
Seagate or Quantum may have it too.

klein_b@a1.wdc.com