crichmon@digi.lonestar.org (Charles Richmond) (09/29/90)
I would like to know what it would take to add some circuitry to an audio CD player so that a computer could read a CD rom on it. Any references on understanding the guts of an audio CD player would certainly help. Perhaps the computer reading circuitry would need to connect to the laser transducer directly? Of course, any schematics would help also. Please enlighten me with your ideas on this subject . . . I am open to suggestions on how to proceed. Charles Richmond crichmon@digi.lonestar.org
whit@milton.u.washington.edu (John Whitmore) (09/30/90)
In article <1043@digi.lonestar.org> crichmon@digi.lonestar.org (Charles Richmond) writes: >I would like to know what it would take to add some circuitry to >an audio CD player so that a computer could read a CD rom on it. > >Any references on understanding the guts of an audio CD player would >certainly help. Almost all audio CD players have a custom LSI chip that handles the track detection/subcode decoding/complex interleave functions. This may (if you're lucky) be a general purpose microprocessor with a plug-in EPROM. Then you can read the EPROM, disassemble it, and change the behavior. Otherwise, that LSI chip will be carefully identifying the non-music tracks and skipping them. There is no way to make a CD player, intended for audio, read the non-audio tracks on a CD-ROM. Some machines do both (I think the Apple CD-ROM reader is one such). Alas, I have perused several references on CD players and there's no joy there. The theory presented is sketchy, the mechanical details are dismissed with handwaving, and the electronics is treated as a black box to be replaced if it gives trouble. I have schematics for one player, and it's obvious that nothing much can be done to change its behavior; the MSM6404RS chip that controls the various machine operations might be possible to replace/reprogram, but it has dedicated on-chip program ROM; I know of no way to read out the existing program for analysis (and lotsa luck getting that info from the manufacturer). John Whitmore
henry@zoo.toronto.edu (Henry Spencer) (09/30/90)
In article <1043@digi.lonestar.org> crichmon@digi.lonestar.org (Charles Richmond) writes: >I would like to know what it would take to add some circuitry to >an audio CD player so that a computer could read a CD rom on it. Probably a lot. The two disk formats are not the same (in particular, the CDROM needs much better error detection and correction -- minor bit rot in music is very hard to notice) and the audio hardware will almost certainly be a single-point design built for audio and nothing else. -- Imagine life with OS/360 the standard | Henry Spencer at U of Toronto Zoology operating system. Now think about X. | henry@zoo.toronto.edu utzoo!henry