S/PDIF User bit

[ebrewste]

I was moving along in a DAC project that used the user bit to get various info (volume, etc.) from a remote. I had the idea that I would strip the user bit further upstream and insert my own data on said bit.

It then occurred to me that I don't know what that bit is used for (other than the non-descript user data). Does anyone know of valuable data to a DAC I would be clobbering? I couldn't find any concrete examples.

 

[guygrand]

User bit

I believe that is what the user bit is for Read the Crystal Semiconductor data sheets for the CS8412.

http://www.crystal.com

Guy

 

[peranders]

It then occurred to me that I don't know what that bit is used for (other than the non-descript user data). Does anyone know of valuable data to a DAC I would be clobbering? I couldn't find any concrete examples.

The user bit is for you, sort of speaking. A normal DAC doesn't pay any attention to this bit only the "C" bit.

I have a small connector on my CD, DENON DCD-1500 from 1986. Sub text? Or? This was used for something and I think it was the user bit was involved here. Can anybody fill in?

Despite the fact that the gentleman above is banned, he has a point. Check the datasheets of CS8402/12/04/14 etc, they say something.

http://www.crystal.com/design/products/overview/detail.cfm?d=54
http://www.crystal.com/design/products/overview/detail.cfm?d=57
http://www.crystal.com/design/products/overview/detail.cfm?d=1005

 

[ebrewste]

Guy et al and peranders, thanks for the replies. I must admit that in doing past projects with the 8414 I never understood what the user bit was used for in existing products. I always supposed that it was used in cd text and other similar features.

I guess I'll be reading for a while...