Cirrus Logic CS8420 - Manual (Page 53)

DS245F4 53
CS8420
EMPH - Pre-Emphasis Indicator Output
EMPH is low when the incoming AES3 data indicates the presence of 50/15
μs pre-emphasis. When the AES3 data
indicates the absence of pre-emphasis or the presence of other than 50/15 μs pre-emphasis EMPH is high. This is
also a start-up option pin, and requires a 47 k
Ω resistor to either VD+ or DGND, which determines the AD2 address
bit for the control port in I²C mode.
Audio Output Interface:
SDOUT - Serial Audio Output Port Data Output
Audio data serial output pin.
OSCLK - Serial Audio Output Port Bit Clock Input or Output
Serial bit clock for audio data on the SDOUT pin.
OLRCK - Serial Audio Output Port Left/Right Clock Input or Output
Word rate clock for the audio data on the SDOUT pin. The frequency will be at the output sample rate (Fso)
AES3/SPDIF Transmitter Interface:
TCBL - Transmit Channel Status Block Start
This pin can be configured as an input or output. When operated as output, TCBL is high during the first sub-frame
of a transmitted channel status block, and low at all other times. When operated as input, driving TCBL high for at
least three OMCK (or RMCK, depending on which clock is operating the AES3 encoder block) clocks will cause the
next transmitted sub-frame to be the start of a channel status block.
TXN, TXP - Differential Line Driver Outputs
Differential line driver outputs, transmitting AES3 type data. Drivers are pulled to low while the CS8420 is in the reset
state.
Control Port Signals:
SCL/CCLK - Control Port Clock
SCL/CCLK is the serial control interface clock, and is used to clock control data bits into and out of the CS8420.
AD0/CS - Address Bit 0 (I²C) / Control Port Chip Select (SPI)
A falling edge on this pin puts the CS8420 into SPI Control Port mode. With no falling edge, the CS8420 defaults to
I²C mode. In I²C mode, AD0 is a chip address pin. In SPI mode, CS is used to enable the control port interface on
the CS8420.
AD1/CDIN - Address Bit 1 (I²C) / Serial Control Data In (SPI)
In I²C mode, AD1 is a chip address pin. In SPI mode, CDIN is the input data line for the control port interface
SDA/CDOUT - Serial Control Data I/O (I²C) / Data Out (SPI)
In I²C mode, SDA is the control I/O data line. SDA is open drain and requires an external pull-up resistor to VD+. In
SPI mode, CDOUT is the output data from the control port interface on the CS8420.