XMOS-based Asynchronous USB to I2S interface

[Lorien]

WaveIO's I2S port is configured in 32 + 32 bit format. More infos can be found here starting from page 24.
Kind regards,
L

[qusp]

Originally Posted by regal

I am surprised it helped the nfb-12, I have one but it measures high distortion (starts with -80dB 2H) stock. Was planning on adding an arudino along with the WaveIO with a new enclosure and better output stage. Glad this turned out good for you.

hehe wow that is epically bad for a dac! and a solid state one at that.

[Porfido]

Originally Posted by regal

I am surprised it helped the nfb-12, I have one but it measures high distortion (starts with -80dB 2H) stock. Was planning on adding an arudino along with the WaveIO with a new enclosure and better output stage. Glad this turned out good for you.

Let's say that the Xmos vs NFB12 Tenor is a sure winner, but the Dac keeps its limits, that's for sure...
Does it really measure so bad?
I'm asking because others seem to report not so bad mesaurements:
http://supercurio.project-voodoo.org...-96k-24bit.htm
http://supercurio.project-voodoo.org...-44k-24bit.htm
http://supercurio.project-voodoo.org...192k-24bit.htm
http://supercurio.project-voodoo.org...amplerates.htm
http://supercurio.project-voodoo.org...upsampling.htm

Sorry, I realize I'm totally OT....

[triode_al]

Originally Posted by hochopeper

If Lorien or someone who knows the answer could answer this question about waveio output being 24+24 or 32+32 I'd be interested also.

This is found on page 29 (SPDIF):

The interface is normal channel with streaming built-ins (outuint, inuint). Data format is 24-bit left-aligned in a 32-bit word: 0x12345600

In the xmos refernce implementation the DAC cs4270/cs4244 is running 24 bits.

My conclusion is: the xmos chip runs the 24 bits format (24L+24R) in i2s.
By the way, the software description also says any i2s dac can be used:

Although the reference designs use the Cirrus CS4270/CS42448, any CODEC that supports I2S and can be used.

for me this is essential as this is the only way in which the board can be 'open', usefull for playing.
albert

[regal]

Originally Posted by Porfido

Let's say that the Xmos vs NFB12 Tenor is a sure winner, but the Dac keeps its limits, that's for sure...
Does it really measure so bad?
I'm asking because others seem to report not so bad mesaurements:
RightMark Audio Analyzer test : NFB-12 96/24
RightMark Audio Analyzer test : NFB-12 44/24
RightMark Audio Analyzer test : NFB-12 192/24
RightMark Audio Analyzer test: comparison
RightMark Audio Analyzer test: comparison

Sorry, I realize I'm totally OT....

Yep same as I got. .015%THD ~ -77dB, mostly 2H.

[qusp]

worse than an ipod at 16/44 when operating at 24/192 now thats an effort

[regal]

Originally Posted by qusp

worse than an ipod at 16/44 when operating at 24/192 now thats an effort

sounds bad too

[Lorien]

Originally Posted by triode_al

In the xmos reference implementation the DAC cs4270/cs4244 is running 24 bits

Yes, because that DAC chip can't handle more than 24-bit resolution.

Originally Posted by triode_al

My conclusion is: the xmos chip runs the 24 bits format (24L+24R) in i2s.

If you're referring only to the actual number of bits using for conversion then yes, WaveIO's I2S serial post could be considered to be 24L + 24R BUT, in fact it's 32(L) + 32(R) from which only 24 bits are effectively used.
Please see again this document at page 25 when it says:

p_sdin and p_sdout are configured as buffered ports with a transfer width of 32, so all 32 bits are input in one input statement. This allows the software to input, process and output 32-bit words, whilst the ports serialize and deserialize to the single I/O pin connected to each port.

... this statement can be found after Table 10:

In any case, the bit clock outputs 32 clock cycles per sample

.. and this will prove that it's a 32-bit/channel I2S interface:

p_lrclk is clocked by p_bclk. The port outputs the pattern 0x7fffffff followed by 0x80000000 repeatedly. This gives a signal that has a transition one bitclock before the data (as required by the I2S standard) and alternates between high and low for the left and right channels of audio.

Convert into binary the hex number 0x80000000 and count the bits.
Kind regards,
L

[audiodesign]

Lorien, news about the new board ?

[Lorien]

I've test your card today (at home) and it's working as expected though I must customize it and cleaned it up before sending to you. I have to wait few more days to feel better though... before getting back to work and send your WaveIO board.