bernid wrote: > Congrats, Great plans!!! > Will there be an option to connect external DAC via I2S interface? > Will I be able to connect an external MasterClock?
Wow, that opens up a can of worms. There are so many different ways this can be used it's going to be difficult to come up with the definitive implementation. First off, what is the physical model here, is this the case of one box talking to another box with a cable in-between, or is it the raw board sitting on top of another board in the same box? This makes a BIG difference as to the interface used. If going between boxes I would insist on using LVDS, it's the only commonly used method of transporting I2s between boxes that is any good. Then there is the issue that the somewhat of a standard approach of LVDS over HDMI cables is just a one way interface, the DAC is not in charge of the clocking. If you want to use a system where the DAC is in control, how many clocks and what frequencies do you send? The player uses two clock frequencies, one for each sample rate family, does the DAC send both frequencies and the player muxes them or does the player send a select signal and the DAC does the muxing? An HDMI interface can do the latter, but doesn't have enough pairs to send two clocks back. A DVI connector has enough pairs, but I don't know of any available DACs (other than full DIY ones) that do this. If this is to be used between boards in the same box you have a little more flexibility, but also zero standards which makes it difficult to do something that might work for more than one specific board. You still have the issues of who is supplying the clock and where it is muxed etc. Then there is the issue of how to select the clocking source, the simplest is just a jumper on the board, but you have take it apart to change source. Or you could have yet another clock mux, which has to driven by some control source, a switch on the front or back? A GPIO from the CPU which can be controlled from the WEBUI? There are SOOOO many possibilities here that I am a bit leery of doing this, I'll get it right for one person, and everybody else will be up in arms because it does not work for their specific implementation. I want to think long and hard about this one and get some sort of consensus about a specific implementation before I even think about implementing it. John S. ------------------------------------------------------------------------ JohnSwenson's Profile: http://forums.slimdevices.com/member.php?userid=5974 View this thread: http://forums.slimdevices.com/showthread.php?t=97881 _______________________________________________ discuss mailing list [email protected] http://lists.slimdevices.com/mailman/listinfo/discuss
