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P4
Line Level
Input
A
2.12.2 Digital Interface
The serial interface of the codec transfers digital audio data and control data into and out
of the device. The SSI port, which consists of independent transmitter and receiver
sections, is used for serial communication with the codec.
On the hybrid controller side, the Serial Transmit Data, STD, pin is an output when data is
being transmitted to the codec. The Serial Receive Data, SRD, pin is an input when data is
being received from the codec. These two pins are connected to the codec Serial Data
Input, SDIN, and Serial Data Output, SDOUT, pins.
The hybrid controller's Transmit Serial Clock, STCK, pin provides the serial bit rate clock
for the SSI interface. It is connected to the codec Serial Port Clock, SCLK, pin. Data is
transmitted on the rising edge of SCLK and is received on the falling edge of SCLK.
The hybrid controller's GPIO PORT D Bit 0 pin, PD0, is programmed to control the
codec's Active Low Reset, RESET, signal.
The Serial Transmit Frame Sync pin, STFS, is programmed to control the codec's Frame
Sync, FSYNC, signal. FSYNC is sampled by SCLK, with a rising edge indicating that a
new frame is about to start. The FSYNC frequency is always the system's sample rate. It
may be an input to the codec, or it may be an output from the codec in data mode.
The basic codec digital connections are shown in
The codec's MODE is set by the three MODE selection resistors, R96-R98. In the factory
default setting of MODE 4, the codec is set to be the Master of the SPI bus with its data
word set at 32 bits per frame; i.e., 16 bits, Left channel and 16 bits, Right channel. The
sample rate is selected on Sample Rate Selector switch S4; reference
selection options. Codec control information is sent over a separate serial port using: PD1
2-14
Freescale Semiconductor, Inc.
CS4218
RIN1
LOUTL
LIN1
LOUTR
Figure 2-10. Codec Analog Connections
56F826 Evaluation Module Hardware User's Manual
For More Information On This Product,
Go to: www.freescale.com
P5
P6
LM4880
Figure
2-11.
Table 2-7
Line Level
Output
A
Headphone
Output
A
for
MOTOROLA
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