Datasheet
AUDIO SERIAL PORT OPERATION
AUDIO DATA INTERFACE FORMATS AND TIMING
LRCK
Ch1(DIN1)orCh3(DIN2)
Ch5(DIN3)orCh7(DIN4)
0
12L
M
N
0
12LM
N
MSB
MSB
LSB
LSB
Ch2(DIN1)orCh4(DIN2)
Ch6(DIN3)orCh8(DIN4)
BCK
DIN1/2/3/4
PCM1690
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.............................................................................................................................................. SBAS448A – OCTOBER 2008 – REVISED JANUARY 2009
The PCM1690 audio serial port consists of six signals: BCK, LRCK, DIN1, DIN2, DIN3, and DIN4. BCK is a bit
clock input. LRCK is a left/right word clock input or frame synchronization clock input. DIN1/2/3/4 are the audio
data inputs for VOUT1 – 8.
The PCM1690 supports 10 audio data interface formats: 16-/20-/24-/32-bit I
2
S, 16-/20-/24-/32-bit left-justified,
24-bit right-justified, 16-bit right-justified, 24-bit left-justified mode DSP, 24-bit I
2
S mode DSP, 24-bit left-justified
mode TDM, 24-bit I
2
S mode TDM, 24-bit left-justified mode high-speed TDM, and 24-bit I
2
S mode high-speed
TDM. In the case of I
2
S, left-justified, and right-justified data formats, 64 BCKs, 48 BCKs, and 32 BCKs per
LRCK period are supported; but 48 BCKs are limited in 192/384/768 f
S
SCKI, and 32 BCKs are limited in 16-bit
right-justified only. In the case of TDM data format in single rate, BCK, LRCK, and DIN1 are used. In the case of
TDM data format in dual rate, BCK, LRCK, and DIN1/2 are used. In the case of high-speed TDM format in dual
rate, BCK, LRCK, and DIN1 are used. In the case of high-speed TDM format in quad rate, BCK, LRCK, and
DIN1/2 are used. TDM format and high-speed TDM format are supported only at SCKI = 512 f
S
, 256 f
S
, 128 f
S
,
and f
BCK
≤ f
SCKI
. The audio data formats are selected by MC/SCL/FMT in hardware control mode and by control
register settings in software control mode. All data must be in binary twos complement and MSB first.
Table 5 summarizes the applicable formats and describes the relationships among them and the respective
restrictions with mode control. Figure 22 through Figure 28 show 10 audio interface data formats.
Table 5. Audio Data Interface Formats and Sampling Rate, Bit Clock, and System Clock Restrictions
CONTROL MAX LRCK
MODE FORMAT DATA BITS FREQUENCY (f
S
) SCKI RATE (xf
S
) BCK RATE (xf
S
) APPLICABLE PINS
16/20/24/32
(1)
192 kHz 128 to 1152
(2)
64, 48 DIN1/2/3/4
I
2
S/Left-Justified
Right-Justified 24, 16 192 kHz 128 to 1152
(2)
64, 48, 32 (16 bit)
(3)
DIN1/2/3/4
24 192 kHz 128 to 768 64 DIN1/2/3/4
I
2
S/Left-Justified DSP
Software
24 48 kHz 256, 512 256 DIN1
control
I
2
S/ Left-Justified TDM
24 96 kHz 128, 256 128 DIN1/2
24 96 kHz 256 256 DIN1
High-Speed
I
2
S/Left-Justified TDM
24 192 kHz 128 128 DIN1/2
16/20/24/32
(1)
192 kHz 128 to 1152
(2)
64, 48 DIN1/2/3/4
I
2
S
Hardware
24 48 kHz 512 256 DIN1
control
I
2
S TDM
24 96 kHz 256 128 DIN1/2
(1) 32-bit data length is acceptable only for BCK = 64 f
S
and when using I
2
S and Left-Justified format.
(2) 1152 f
S
is acceptable only for f
S
= 32 kHz, BCK = 64 f
S
, and when using I
2
S, Left-Justified, and 24-bit Right-Justified format.
(3) BCK = 32 f
S
is supported only for 16-bit data length.
Figure 22. Audio Data Format: 16-/20-/24-/32-Bit I
2
S
(N = 15/19/23/31, M = 14/18/22/30, and L = 13/17/21/29)
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