Cirrus Logic CS492 Series, Руководство пользователя

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CDB4923 CDB49300
16 DS262DB2
7. INPUT
7.1 Analog Input
A stereo input is provided at RCA jacks J55 and
J56. These inputs are designed to accept a full-scale
signal of 2 V
rms
. Each single-ended signal is con-
verted to a differential 2 V
rms
signal before being
applied to the inputs of the CS5334 ADC. The
CS5334 and its analog input buffers can be found
in Figure 9.
The CS5334’s clock signals can be accessed at the
test points labeled ALG_MCLK, ALG_SCLK, and
ALG_LRCLK (these test points can be found in
Figure 11). The serial data stream coming from the
CS5334 can be probed at the 34SDATA test point
(TP22). Jumper J52 is used to configure the
CS5334 for slave or master mode. The default,
slave mode, is used when the CS5334 accepts all
clock signals from another source. When in master
mode, the CS5334 accepts MCLK and generates
SCLK and LRCLK. The CDB4923/300 is config-
ured to use the CS5334 in slave mode only. Please
contact the factory for details on how to use the
CS5334 in master mode.
The digital output format of the CS5334 can be
configured with switch S4 as described in Table 14.
More details on the CS5334 can be found in the
CS5334 datasheet.
7.2 Digital Input
There are two possible sources of digital audio for
the CDB4923/300: S/PDIF, and bursty delivery
from the host PC across the parallel interface.
Bursty delivery is accomplished by spooling a file
from the host PC to the CDB4923/300 using the
PARLLPLY.EXE program found on the included
floppy. Audio delivered across the S/PDIF inter-
face comes from a digital source such as a DVD
player.
The S/PDIF inputs are J30 (RCA) and J32 (Opti-
cal), and can be found in Figure 10. It is vital to
note, though, that only one of these S/PDIF inputs
can be used at any given time. The active jack is de-
termined by the setting of jumper J31 (S/PDIF IN).
When J31 is in the ’OPT’ position, S/PDIF data will
be accepted only from J32. When J31 is in the
’RCA’ position, S/PDIF data will be accepted only
from J30.
The S/PDIF signal is routed to the CS8414 receiver
(U13). The digital output format of the CS8414 is
configured using switch S1 as described in Table
15. The CDB4923/300 comes from the factory con-
figured to operate in I
2
S mode. Note that this de-
fault should not be changed unless the DSP has
been configured to use a different serial format.
Jumpers J65 and J66 control the SEL and
CS12/FCK pins of the CS8414. These pins can be
used to select what is displayed on the channel sta-
tus outputs of the Digital Audio Interface Receiver.
By default these pins are pulled up and the jumpers
are not stuffed. If the user wishes to change the val-
ues of these pins a stake header should be installed.
The CS8414, its control switch, and jumpers can be
found in Figure 10. If more details on the CS8414
are needed, please reference the CS8414 datasheet.
34DIF1 34DIF0 Digital Input Format
LO LO 20-Bit Left Justified, Rising SCLK
LO HI 20-Bit Left Justified, Falling SCLK
HI LO
20 Bit I
2
S, Rising SCLK (default)
HI HI Power Down
Table 14. CS5334 Digital Output Formats (S4)
M2 M1 M0 Audio Serial Port Format
LO LO LO Out, L/R, 16-24 Bits
LO LO HI In, L/R, 16-24 Bits
LO HI LO
Out, L/R, I
2
S
LO HI HI
In, L/R, I
2
S (default)
HI LO LO Out, WSYNC, 16-24 Bits
HI LO HI Out, L/R, 16 Bits LSBJ
HI HI LO Out, L/R, 18 Bits LSBJ
HI HI HI Out, L/R, MSB Last
Table 15. Digital Output Format settings
for CS8414 (S1)