24-Bit, 192-kHz Sampling, Advanced Segment, Audio Stereo DAC ...

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Device ID = 1
Device ID = 2
Device ID = 3
•
•
•
Device ID = 30
LRCK
BCK
DI
DCO1
DCO1
DCI2
DCO2
DCI3
•
•
•
DCO29
DCI30
DID
Command Field
58 BCK
Figure 57. Device ID Determination Sequence
SLES105B − FEBRUARY 2004 − REVISED NOVEMBER 2006
TDMCA Frame
In general, the TDMCA frame consists of the command field, extended command (EMD) field, and audio data
fields. All of them are 32 bits in length, but the lowest byte has no meaning. The MSB is transferred first for each
field. The command field is always transferred as the first packet of the frame. The EMD field is transferred if
the EMD flag of the command field is HIGH. If any EMD packets are transferred, no audio data follows the EMD
packets. This frame is for quick system initialization. All devices of a daisy chain should respond to the command
field and extended command field. The PCM1792A has two audio channels that can be selected by OPE
(register 19). If this OPE bit is not set to HIGH, those audio channels are transferred. Figure 58 shows the
general TDMCA frame. If some DACs are enabled, but corresponding audio data packets are not transferred,
the analog outputs are unpredictable.
LRCK
BCK
[For Initialization]
[For Operation]
Don’t
DI CMD EMD EMD EMD EMD
EMD CMD
32 Bits
DO CMD CMD CMD CMD CMD CMD
DI
CMD Ch1 Ch2 Ch3 Ch4
Ch(n) CMD
DO CMD Ch1 Ch2 Ch3 Ch4
Ch(m)
1/fS
Figure 58. General TDMCA Frame
Care
Don’t
Care
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