CDB42406

15

1.8

Stand-Alone Control

Switches S1-S4 allow signal routing and configuration of the CDB42406. Switch S1 controls

the interface format of the CS8416 and allows selection between the OPTICAL and COAXIAL

S/PDIF inputs. The DAC portion of the CS42406 may operate in either stand-alone (config-

ured using switch S2) or control port mode (configured via the PC Parallel Port through a

graphical user interface). The ADC portion of the CS42406 operates in stand-alone mode at

all times and must be configured using switch S3. Switch S4 controls the routing of all clocks

and data. See section 1.7 for a list of the various stand-alone options available. After setting

any of these switches, the user must assert a reset by pressing the RESET button (S5).

Operation in stand-alone mode requires the parallel port cable to remain disconnected from

the DB-25 connector (J24). Connecting a cable to the connector will enable the PC control

port, automatically disabling various controls on switch S2.

1.9

PC Parallel Port Control

A graphical user interface is included with the CDB42406 to allow easy manipulation of the

DAC registers of the CS42406. Connecting a cable to the DB-25 connector (J24) will enable

the PC control port, automatically disabling various controls on switch S2.

1.10 External Control Headers

The evaluation board has been designed to allow interfacing with external systems via the

headers J15 and J26.

The 32-pin header, J15, provides access to the serial audio signals required to interface with

a DSP (see Figure 24). These signals are routed based on the setting of switch S4. See

“CPLD Board Setup” in section 1.7 for various setup options for DSP routing.

signals on J26 default to outputs. When a cable is connected to the DB-25 connector (J24),

the header (J26) may be used as an input. In this case, the control signals on J26 are routed

to the corresponding control pins on the CS42406 and external control signals may be ap-

plied.