CS4922

30

Serial Control Port

REQ - Request Output, PIN 3.

This pin is driven low when the DSP needs servicing from an external device. A write to the

SCPOUT will cause the REQ to go low. A pull-up resistor is required for proper operation

(2.2k

Ω is typical).

CS - Chip Select Input, PIN 44.

In SPI format, all communication between the host and the CS4922 is initiated when the host

drives the CS pin low. This pin also serves as the communication format select during a reset

mode. When low, it is configured in SPI mode. The mode is selectable in software by setting

the M0 bit in the SCPCN.

SCK/SCL - Serial Clock Input, PIN 2.

SCK/SCL clocks data into or out of the serial control port. This is always driven by an external

device because the CS4922 always operates in slave mode.

SDA/CDOUT - Serial Data I/O / Control Data Output, PIN 4.

is a bi-directional data I/O.

It is required that a pull-up be used (2.2 k

mode).

CDIN - Control Data Input, PIN 1.

systems.

Auxiliary Digital Audio Port

AUXLR - Auxiliary Sample Clock, PIN 10.

This output signal determines which channel is currently being input on the AUXIN pin or

output on the AUXOUT pin. It is also the sample clock, Fs.

AUXIN - Auxiliary Data Input, PIN 9.

Two’s complement MSB first serial data is input on this pin. The data is clocked by AUXCLK

and the channnel is determined by AUXLR.

AUXOUT - Auxiliary Data Output, PIN 8.

Two’s complement MSB first serial data is output on this pin.

The data is clocked by

AUXCLK and the channel is determined by AUXLR.

AUXCLK - Auxiliary Serial Clock Output, PIN 11.

This is the auxiliary audio port serial clock output. This output is used to clock data in on the

AUXIN pin and shift data out on the AUXOUT pin. Its frequency is selectable in software.