Customer question: details about SPDIF vs AES3.
Depending on received HDMI stream - receiver can provide two types of interfaces that seem to be similar:
AES3/"RAW SPDIF" or standard SPDIF (IEC60958)
Below table shows differences between those two modes.
block start flag
YES (in parity bit slot)
And finally picture below shows timing differences between them.
I2S can be selected by setting I2SOUTMODE to 2'b00.
Data contains always 32 clocks per sample, regardless of actual real bit depth (bits per sample); in other words - samples
bits are always padded to produce 32 clocks/bits per sample.
For more details refer to: http://www.analog.com/static/imported-files/user_guides/UG-216.pdf
Quote from Your answer:"AES3/"RAW SPDIF" or standard SPDIF (IEC60958)".
But UG-216 ( Rev. B ) page 67 describes I2SOUTMODE[1:0]=11 as RAW SPDIF (IEC60958) which is a mixture from two different modes as from the above quote.
My personal Q.:
Can ADV7612 output the following waveform without biphase encoding ( don't care about aud_de ):
If Yes, then how it is called in terms of UG-216?
No I'm afraid in RAW SPDIF/AES3 mode, the ADV7612 does not output a pre-amble. See Figure 70 from Witos post.
UG-216 ( Rev. B ) page 67 describes I2SOUTMODE[1:0]=11 as RAW SPDIF (IEC60958).
If RAW SPDIF = IEC60958, then according to Fig.69 ( both from vito's post and UG-216 ) IEC60958 is shown with pre-amble and can be selected by setting I2SOUTMODE[1:0]=11.
Is it really true?
I'm not convinced the datasheet is correct here. I'll have to check this on a 'scope, Unfortunately it will be next week before I get to this.
Sorry for the delay,
I finished checking this on a 'scope and the ADV761X receivers output audio packets as per that shown in figure 70 when raw SPDIF mode is enabled. Unfortunately, there is no preamble. I'm not sure if it is correct to call this AES3 and definitely not IEC60958.
Thank You, Paul, for Your help!
Where is then that raw SPDIF mode is intended to be used?
What devices can accept it?
What the word "raw" here means?
If raw SPDIF was really SPDIF, but without biphase modulation, then it could be really useful.
I guess there is a block start flag which can be used to synchronise every 192 frames. This could be used in an FPGA design anyway. I'm unsure what audio codecs support this format though we have had plenty of customers use it.
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