CRD-42528 Cirrus Logic Inc, CRD-42528 Datasheet - Page 7

• Manufacturer Part Number: CRD-42528
• Description: Audio Modules & Development Tools Reference Design for CS42528 + CS493XX
• Manufacturer: Cirrus Logic Inc

Specifications of CRD-42528

• Product: Audio Modules
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

2. DESIGN DESCRIPTION
2.1 Clock and Data Connections
There are 2 main modes of operation of the
CRD42528, Analog Input Mode and Digital Input
Mode. In Analog Input Mode, up to 8 channels of
analog input can be processed by the DSP. In Dig-
ital Input Mode, S/PDIF (IEC61937/IEC60958)
data is sent to the DSP for decoding or processing.
In both cases, the output from the DSP is sent back
to the CS42528 to generate analog output.
2.1.1 Analog Input Mode
A detailed diagram of the clock and data connec-
tions for analog input mode can be found in
Figure 4, “Data and Clock Connections for 8 Chan-
nel Analog Input and Output,” on page
Analog Input Mode is used, the CRD42528 will
process up to 8 channels of analog input. The ana-
log source is the analog I/O connectors on the
UDSP MainBoard, which are routed directly to the
CRD42528. The Left (L) and Right (R) analog in-
puts are connected, via input filters, to the
CS42528’s analog input pins. When 6 channel (re-
ferred to as 5.1 channel) input is desired, two exter-
nal CS5351 Analog to Digital Converters are used.
These external ADCs receive the RMCK output
from the CS42528. In this mode, RMCK will pass
through the 12.288 MHz oscillator connected to
OMCK. The external ADC serial ports are driven
from the CS42528’s CX port clocks. The Left Sur-
round (Ls), Right Surround (Rs), Center (C), and
Subwoofer (Sub) inputs to the CRD42528 are con-
nected to the external CS5351’s analog inputs, and
the digital outputs from the two external CS5351s
is then connected to the CS42528’s ADCIN1/2
pins. The CS42528 will incorporate all of the data
from the external ADCs and it’s own analog input
data onto a single line and send it to the DSP via the
CS42528’s SAI port. In this way, the DSP gets the
L, R, Ls, Rs, C, and Sub channels into it’s CDI port.
For 7 or 8 channel (6.1 or 7.1 channel) operation,
another external CS5351 is used to convert the Sur-
round Back Left (SBL) and Surround Back Right
(SBR) analog inputs. Please note that many appli-
10. When
cations use a single mono surround channel, re-
ferred to as Surround Back (SB). The digital output
from the CS5351 is sent directly to the DSP’s DAI
port.
Once the DSP has processed the incoming digital
inputs, data is returned to the CS42528 to be con-
verted back to analog. The data, coming from the
DSP’s DAO port, is clocked by the CS42528’s CX
port clocks.
2.1.2 Digital Input Mode
A detailed diagram of the clock and data connec-
tions for analog input mode can be found in
Figure 5, “Clock and Data Connections for S/PDIF
(IEC61937 / IEC60958) Input,” on page
process incoming S/PDIF (IEC61937/IEC60958)
data streams, digital input is wired directly from the
UDSP’s optical receivers to the CS42528. The
CS42528 will then lock to the incoming stream and
convert it to an I
to the DSP from the CS42528’s SAI port. This data
is input on the DSP’s CDI port. The DSP will pro-
cess this stream (i.e., decode the compressed
stream or process the PCM data), and then send up
to 8 channels of I
DAO port. This PCM data is input on the
CS42528’s CX port. The CS42528 then converts
the audio data back to analog.
2.2 Control
Control of the CRD42528 is done via the UDSP
headers (J2 and J3) in either SPI or I
ferent resistors must be populated or not populated
according to the desired communication mode.
These options can be found in
For I
address checking disabled. This can only be
changed after a firmware image has been loaded
onto the DSP (either via host boot or autoboot).
Please see the CS49300 datasheet for more details
on I
2
2
C address checking.
C mode, please note that the DSP defaults to
2
S data stream, which is then sent
2
S data to the CS42528 on it’s
Table
2
1.
C mode. Dif-
11. To
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