This means that, in theory, SB2 is capable of playing 2-channel high resolution 192/24 DVD-Audio both to analog and digital output?
Steinar > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:discuss- > [EMAIL PROTECTED] On Behalf Of Sean Adams > Sent: 9. mars 2005 22:10 > To: Slim Devices Discussion > Subject: Re: [slim] SB2 and PCM formats > > > DISCLAIMER: please be very clear that these are not promises that we're > going do any particular feature at any particular time, or even at all. > I will comment *to the best of my knowledge* on what the hardware could > potentially be made to do, but please don't hold me to it if we find > some reason later why some particular thing can't or won't be done. > > Right now Squeezebox2 does 24 bits (s/pdif and DAC) at 44.1 and 48KHz. > > A block diagram is in order: > > > ---------------- > | ip3023 cpu | > ---------------- > | > | > ---------------- > | |----- 11.2896 mhz > |xc9536xl CPLD | > ---| |----- 12.2880 mhz > | | | > | ---------------- > | | | ------------------- > | | |_________| S/PDIF outputs | > | | ------------------- > | ------- > | | DAC | > | ------- > | | -------- ______________ > | +--------| AMP |------| RCA Outputs | > | | -------- -------------- > | | > | ---------- --------- -------------- > +----| CMOS |----| AMP |------| Headphone/ | > | | SWITCH | --------- | geekport | > | --------- --------------- > | | > |------------------------------------| > > > > The really important thing to note here is that there are NONE of the > usual "hard-wired" digital audio components that you'd expect to see. > S/PDIF outputs are usually done using a chip like the CS8405. Also, > often times there will be some "audio codec" chip in the path, which > handles gain, mixing, resampling and stuff like that. We are doing ALL > of this stuff in software, which gives us tremendous flexibility to > tweak, tune, and improve it. > > The other important point is that the digital logic which handles the > s/pdif outputs and the feeding of data to the DAC is all done in a > Xilinx gate array. If you're not familiar with CPLDs or FPGAs, > basically the idea is that instead of hard-wiring a bunch of individual > logic chips together or making a custom integrated circuit, these > programmable gate arrays allow you to create your own custom chip by > writing code. The _really_ killer thing about them is that you can > reprogram them later, which in terms of standard logic chips, is the > equivalent of making a whole new circuit board in "software". In > squeezebox2 this Xilinx chip is configured by the CPU, so we have the > ability to completely "rewire" the digital output path just about any > way we want, at any time. Hence there are some extremely interesting > possibilities for future features.... > > Finally, notice the geekport. Squeezebox1 had a geekport too, but it > was not really accessible because you had to open the case and solder > stuff onto the board. In Squeezebox2, the geekport is the headphone > jack! The headphone jack can be reconfigured for other modes, including > bidirectional data and IR blasting. These features are not done yet but > the hardware support is there. > > Everything below this line is a ** POSSIBLE MAYBE SOMETIME DOWN THE > ROAD **. > -------------------- > > - The hardware has SEPARATE DATA PATHS for s/pdif and DAC outputs. We > are not using this capability now (both are fed the same data), but it > could be used perhaps for some interesting multi-channel applications. > For example, we could output the encoded digital stream to a surround > receiver, and also output a 2-channel stereo rendition to the DAC. > > - Crsytals can easily be desoldered. The logic is driven directly by > these two oscillators, so if you want to experiment with unusual > frequencies or wire up an aftermarket clock source, you can. > > - 96Khz should be doable with the xtals we have, maybe 192. > > - All the s/pdif data is under our control. We can pretend to be > AES/EBU, lie about what kind of device we are (DAT player etc), shut > off the s/pdif in order to tell an amp or receiver that we're not > active, etc etc. > > - There are some vendor-specific/proprietary tricks that some guys are > doing with s/pdif. In particular, I believe somebody has a receiver + > s/pdif speaker setup that sends volume commands over the s/pdif. We > could support things like this - probably they would be trivial to > reverse-engineer, but we'd prefer to get cooperation. > > - The geekport can potentially do some pretty crazy things - high speed > RS232 for example, auxiliary s/pdif output, house sync (word clock) > input, maybe even s/pdif INPUT, i2c, dallas 1-wire - damn near anything > you can do on two wires + ground. The only geekport feature we're > aiming to finish by ship date is IR blasting. This will allow > Squeezebox2 to power on your receiver and set it to the right input, > and later power it off automatically when you're done listening. The IR > blaster has a variable current driver so it can be set up to drive a > single LED dimly up to multiple LEDs brightly. It could also deliver > enough current to drive a small external voltage regular eg for a > microcontroller which would communicate with the SB2 over dallas > 1-wire. > > > > > On Mar 9, 2005, at 11:44 AM, Steinar Bjaerum wrote: > > > What PCM formats are the DAC in the SB2 capable of delivering to the > > analog > > output? > > All the way up to 96kHz/24bits? > > > > What PCM formats are SB2 capable of passing through to the S/PDIF > > digital > > out? > > > > I am interested in knowing both the current status and the > > possibilities > > with future software upgrades. > > > > Steinar > > > > > > _______________________________________________ > > Discuss mailing list > > [email protected] > > http://lists.slimdevices.com/lists/listinfo/discuss > > > > _______________________________________________ > Discuss mailing list > [email protected] > http://lists.slimdevices.com/lists/listinfo/discuss > _______________________________________________ Discuss mailing list [email protected] http://lists.slimdevices.com/lists/listinfo/discuss
