McBSP I2S on Expansion to talk to an Audio Codec

Is it possible to use Beagleboard expansion connector's McBSP1 signal
to talk to the audio codec on an external HDMI chip like the ADV7511?
Beagle has McBSP1_DX/CLKX/FSX/DR/CLKR/FSR and the ADV7511 audio codec
has I2S[3:0], DSD[5:0], MCLK, LRCLK, SCLK, DSD_CLK.

We built a complete interface to the TI (Burr-Brown) PCM1792A 24-bit stereo DAC
with the BB expansion connector. We used McBSP1_CLKR for the 49.152 MHz SCK,
McBSP3 for the 12.288 MHz I2S interface, and MMC2 signals to implement the
DAC's SPI command interface. Everything works fine even at these high
data rates.
We reprogrammed the DPLLs to get the proper frequencies.

Good luck for your project - let us know your results!

Seppo -

Any chance you could post patches of what you did to enable an off-
board codec? I'm curious to see details of how you accomplished this.


Hi Eric,

We are now building a complete demo system and polishing the working
DAC software. Once we are ready we may or may not make the source code
available. We should be ready in a month.


I was wondering if anyone was able to make progress on this? I am very
interested in doing this.

I was searching for a similar solution. I need 8/16 channel
bidirectional at 48 kHz (96 kHz should be possible without changing
much). Mostly McBSP2 is used by the TWL codec. I used McBSP3 on the
beagle board. For now I can use 8 channel in/out. I have an external
word/bitclock (higher precision), but let the omap create it shouldn't
be a real issue.
I had some trouble with writing a dummy codec driver. So I modified
the TWL code and removed most of the code, because I dont't need
volume control etc. I changed the McBSP port as well as setting the
format to 32 Bit, left justified. Changing this to 24 bit or something
else is only a small change (some Bitfields).
I will describe my changes later, when I'm finished with everything. I
want to clean up before. But if you have questions, I will try to

Great! I'm looking forward to getting a look at your source code. A
working driver for McBSP I2S is something I've been hoping for.