CS42428 CIRRUS [Cirrus Logic], CS42428 Datasheet - Page 16

• Manufacturer Part Number: CS42428
• Description: 114 dB, 192kHz 8-Ch CODEC WITH PLL
• Manufacturer: CIRRUS [Cirrus Logic]

the PLL. In this latter scenario the PLL output becomes the internal master clock. The supported PLL out-
put frequencies are shown in Table 3 below.
The serial bit clock, DAC_SCLK and/or ADC_SCLK, must be synchronous to the corresponding
DAC_LRCK/ADC_LRCK and be equal to 128x, 64x, 48x or 32x Fs depending on the interface format
selected and desired speed mode. One Line Mode #1 is supported in Slave Mode. One Line Mode #2 is
not supported. Refer to Table 4 for required clock ratios.
3.5
3.5.1
The CS42428 interfaces to an external Digital Audio Processor via two independent serial ports, the
DAC serial port, DAC_SP and the ADC serial port, ADC_SP. The digital output of the internal ADCs use
the ADC_SDOUT pin and can be configured to use either the ADC or DAC serial port timings. These con-
figuration bits and the selection of Single, Double or Quad Speed mode for DAC_SP and ADC_SP are
found in register “Functional Mode (address 03h)” on page 33.
The serial interface clocks, ADC_SCLK for ADC_SP and DAC_SCLK for DAC_SP, are used for trans-
mitting and receiving audio data. Either ADC_SCLK or DAC_SCLK can be generated by the CS42428
(master mode) or it can be input from an external source (slave mode). Master or Slave mode selection is
made using bits DAC_SP M/S and ADC_SP M/S in register “Misc Control (address 05h)” on page 36.
The Left/Right clock (ADC_LRCK or DAC_LRCK) is used to indicate left and right data frames and the
start of a new sample period. It may be an output of the CS42428 (master mode), or it may be generated
by an external source (slave mode). As described in later sections, particular modes of operation do allow
the sample rate, Fs, of the ADC_SP and the DAC_SP to be different, but must be multiples of each other.
The serial data interface format selection (left/right justified, I
data out pin, ADC_SDOUT, and the DAC input pins, DAC_SDIN1:4, is configured using the appropriate
16
OMCK/LRCK Ratio
SCLK/LRCK Ratio
Digital Interfaces
Serial Audio Interface Signals
Sample
176.4
(kHz)
Rate
44.1
88.2
192
32
48
64
96
32x, 48x, 64x, 128x
Table 3. Common PLL Output Clock Frequencies
Single Speed
Single Speed
256x, 512x
(4 to 50 kHz)
11.2896
12.2880
8.1920
256x
-
-
-
-
-
Table 4. Slave Mode Clock Ratios
PLL Output (MHz)
(50 to 100 kHz)
Double Speed
Double Speed
128x, 256x
32x, 64x
16.3840
22.5792
24.5760
256x
-
-
-
-
-
2
S or one line mode) for the ADC serial port
(100 to 192 kHz)
Quad Speed
Quad Speed
45.1584
49.1520
256x
32x, 64x
128x
-
-
-
-
-
-
One Line Mode #1
CS42428
256x
128x