CDROM controller - MT1199 any info?

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C

cm

Member
Joined 2003
I wanted to use a computer CDROM as a transport. I did not want to build a display and an IDE interface and hence took the route of trying to get I2S direct and using a CDROM with play pause etc buttons. I got a brand new Creative 52X CDROM for about US$20 . It comes with an IR remote. The remote only works for open and close. I guess it needs software to operate.

Opening up the CD ROM, there are no familiar servo controller or DAC chips, just a giant MT1199 all in one controller chip. Does anyone have info on this chip? I need to know how to connect an external DAC other than via the SPDIF output. I emailed the compnay producing the chip twice but got no reply. Obviously they do not support indirect customers. Also, there is no crystal, just a common 33MHz resonator! The jitter must be really bad.

I opened up several other CDROMs from A Open, Acer and they all use the same chip! Probably the same reference design as well.

Thanks for any help.
 
R

rah

Member
Joined 2003
You'll have better luck with an older cd-rom
drive. The newer cd-roms just use an ASIC
chip to do everything, I don't think you'll find
I2S on any of the pins.

I've looked through a lot of cd-rom drives, and
am now using an older one (MFD. 1995) to get I2S...
 
C

cm

Member
Joined 2003
I e-mailed MediaTek twice asking for datasheet or if that is confidential, then if an external DAC is possible. No reply each time. They are not interested in serving the DIY community. Well, I decide on suppliers for my company ( I am in the mobile phone design business ), and I will not use thier GSM chipset.

I looked around for older drives, especially Philips or Sony. Found a 4X NEC with a CXD2510 with a PCM1715 DAC. Unfortunately, there is no play button. I opened the drive and tried shorting some internal connectors or test points to see if there is a play button that is not soldered for cost reasons - none worked.

I found another older 24x drive. In there is a Toshiba TC9940 servo controller. I found a Japanese datasheet. The I2S signal ( could be EIAJ ) seems to be there but BCK is 1.4MHz??? I thought BCK is 2.11mHz? Therefore no luck there as well.

Mechanically, the Acer is extremely well built and robust. The A Open, NEC and Creative is more flimsy. Anyway, using the SPDIF output, the Acer also gave better quality sound, with more details. However, it is very thin with no life, pretty much the same as my low end CD Pioneer before I made many many mods. I suppose I can use a CS8412 and reclock the I2S before the DAC to eliminate the jitter due to the low cost resonator used in the servo controller.
 
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