ADAU145x Flexible TDM
I have an application where I'm processing a 2-channel TDM input stream in an ADAU1451. I've never used TDM before, so please bear with me for what may be a stupid question.
In SigmaStudio 3.12.1, I enable the FTDM registers in the hardware config as follows, per Fig. 70 of the data sheet:
For the "left" input channel:
FTDM IN0 - Position 0, MSB
FTDM IN1 - Position 1, 2nd MSB
FTDM IN2 - Position 2, 3rd MSB
FTDM IN3 - Position 3, LSB
And for the "right" input channel:
FTDM IN4 - Position 0, MSB
FTDM IN5 - Position 1, 2nd MSB
FTDM IN6 - Position 2, 3rd MSB
FTDM IN7 - Position 3, LSB
The resulting output waveform looks like 8-bits resolution, which I verified with a controlled input level. It's sort of like the 3 lower byte positions are being ignored.
In order to get full resolution, I had to change the "Position" tab on all IN's to "0". The byte assignments were not changed from the above listing.
What am I not getting?
Audio Signal Processors
adau1451
SigmaDSP Audio Processors
Hello John,
You are trying to climb a mountain when you only need to take a walk on the beach. Flexible TDM mode is quite complicated to setup and is only needed to do special things. Just use the standard TDM modes on the serial ports. In addition, if you are using two channel TDM chances are the signals are really I2S. They are very similar and identical in some circumstances.
So just look at the Serial Data Input/output section of the datasheet and you will find this is quite easy.
Dave T
Thanks, Dave, but this would not have been my preference. We are receiving our data from a commercially-available board, the Atterotech DBAM, a Dante network interface, and that's what I have to work with. It works quite well; I just don't understand the channel assignment.
Hello John,
Send over the Dante board's TDM details showing the format and channel assignment and I will have a look.
Dave T
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Thank you,
EZ Admin
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