1998 Oct 06

25

Philips Semiconductors

Preliminary specification

Universal Serial Bus (USB)

Digital-to-Analog Converter (DAC)

UDA1321

Table 9

6-pins digital I/O communication

Filter characteristics

The overall filter characteristic of the UDA1321 in flat mode is given in Fig.8. The overall filter characteristic of the

UDA1321 includes the filter characteristics of the DSP in flat mode plus the filter characteristic of the FSDAC

DSP extension port

An external DSP can be used for adding extra sound processing features via the digital I/O-bus. The UDA1321 supports

Using the 4-pins digital I/O-bus the UDA1321 device acts as a master, controlling the BCK and WS signals. The period

of the WS signal is determined by the number of samples in the 1 ms frame of the USB. This implies that the WS signal

does not have a constant period time, but is jittery. Using the 6-pins digital I/O-bus GP2, GP3 and GP4 are the output

pins (master) and GP0, GP1 and GP5 are the input pins (slave).

PIN

INPUT/OUTPUT

FUNCTION

GP5

digital I/O-bus

WSI

GP4

BCKO

GP3

WSO

GP2

DO

GP1

DI

GP0

BCKI