[the terabyte]

i'm looking to integrate a USB to S/PDIF conversion circuit into my ART DI/O and came across one thing that i was unfamiliar with in the documentation for the chip i'm planning to use. it needs a 12MHz clock source, which won't be a problem to find, but it seems that it's not as simple as poping it into the circuit. below is a diagram of the circuit i plan to use (sans analog stuff, of course):

as you can see, there are two capacitors, C5 and C6, following the crystal, which the white paper says are determined by which crystal you use. my question is: how does one determine this from the specifications of a crystal? thanks.

 

[zzz]

get a parallel crystal (I used 520-HCU1200-20 from mouser) and some 15pf-20pf caps. I believe 20pf is what you're supposed to use with that one but I only had 10pf at hand at the time when I was messing around with this thing and half the time it still worked fine. when it didn't, swapping one of the caps for another from the same batch always did the trick.

you can also get a real 12mhz oscillator, connect it to power, ground, and xti, and avoid all this mess with crystals. I think I have at least at dozen of those here that are not likely to see any use again

.

I still have a bunch of boards for this exact chip for this exact purpose (usb->spdif) and some leftover parts and can hook you up if you want.

 

[the terabyte]

Quote:

Originally posted by zzz get a parallel crystal (I used 520-HCU1200-20 from mouser) and some 15pf-20pf caps. I believe 20pf is what you're supposed to use with that one but I only had 10pf at hand at the time when I was messing around with this thing and half the time it still worked fine. when it didn't, swapping one of the caps for another from the same batch always did the trick. you can also get a real 12mhz oscillator, connect it to power, ground, and xti, and avoid all this mess with crystals. I think I have at least at dozen of those here that are not likely to see any use again . I still have a bunch of boards for this exact chip for this exact purpose (usb->spdif) and some leftover parts and can hook you up if you want.

i've got some samples of the chip on the way, but i'd be great if you could send me an oscillator, and a board. i'll PM you my address, just tell me what i owe you.

also, when you say to connect it to "power," do you mean the +5v coming in from the USB or what? other than that, sounds great.

 

[Glassman]

what drivers are you supposed to use with this nice little USB thing?

 

[the terabyte]

Quote:

Originally posted by Glassman what drivers are you supposed to use with this nice little USB thing?

according to the white paper, they're built into my OS.