Pc -> Dac, How ?

[Gopher]

And you wonder why most people still use CDs?

Seven pages of completely incomprehensible gobbledygook which the average Joe Schmoe hasn't got a clue about.

Get in the real world guys and start listening to music instead of fiddling around with your Operating Systems and low latency Linux embedded kernel drivers.

[jackpipe]

Joe shmoe doesn't build his own audio system, and thinks latency is something he'll get fired for.

[chertk]

Guys
Here it is one interesting kit from Atmel and pretty cheap!
http://www.eetimes.eu/products/analog/215900841

Consider this board as ethernet to i2s
audio streaming player.
Player gets data (wav up to24/192) from external NAS. External DAC connected on I2S as master.
And pretty cheap!

It's just a project in my head - I'm not software buddy, alas :-(
So i don't know could it process all this stuff.

Respect

[francolargo]

Other than MP3, any idea what file types it can play? In general, it sounds like a Squeezebox with no software but I2S output. Yawn.

Frank in Mpls.

[UnixMan]

Originally posted by francolargo
Other than MP3, any idea what file types it can play?

I guess whatever you like... once you provide the code to do so.

[Russ White]

I got one to mess with, should be here later this week.

I have programmed the AVR32 before including a FLAC decoder. Its not that hard.

Should be fun.

Cheers!
Russ

[anbello]

From what i read in the data sheet of the avr32 (a quick read so i hope to be wrong) i2s samples could be only 16 bit long. Is there anyone who can confirm or refute this?

Ciao
Andrea

[Russ White]

Originally posted by anbello
From what i read in the data sheet of the avr32 (a quick read so i hope to be wrong) i2s samples could be only 16 bit long. Is there anyone who can confirm or refute this?

Ciao
Andrea

• DATLEN: Data Length
0: Forbidden value (1-bit data length not supported).
Any other value: The bit stream contains DATLEN + 1 data bits. Moreover, it defines the transfer size performed by the
PDC2 assigned to the Transmit. If DATLEN is lower or equal to 7, data transfers are bytes, if DATLEN is between 8 and 15
(included), half-words are transferred, and for any other value, 32-bit words are transferred.

That means up to 32bit words are possible.

Cheers!
Russ

[Russ White]

OK more detail. Word length can be up to 32 bits and frame length is configurable up to 16 words.

Reading AT32UC3A Datasheet.

Check out table 25-3.

Cheers!
Russ

[anbello]

Thanks for the explanation Russ, i was confused also reading at the alsa driver source for atmel soc.

An excerpt from alsa-driver-1.0.19\alsa-kernel\soc\atmel\atmel_ssc_dai.c

/*
* The SSC only supports up to 16-bit samples in I2S format, due
* to the size of the Frame Mode Register FSLEN field.
*/
if ((ssc_p->daifmt & SND_SOC_DAIFMT_FORMAT_MASK) == SND_SOC_DAIFMT_I2S
&& bits > 16) {
printk(KERN_WARNING
"atmel_ssc_dai: sample size %d"
"is too large for I2S\n", bits);
return -EINVAL;
}

Ciao
Andrea