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STA020

Figure 2. STA020D Typical Connection Diagram.

GENERAL DESCRIPTION

The STA020D is a monolithic CMOS circuit that encodes and transmits audio and digital data according

to the AES/EBU, IEC 958, S/PDIF, and EIAJ CP-340 interface standards. The chip accepts audio and con-

trol data separately; multiplex and biphase-mark encode the data internally and drive it, directly or through

a transformer, to a transmission line.

The STA020D has dedicated pins for the most important control bits and a serial input port for the C, U

and V bits.

Line Drivers

The differential line drivers for STA020D are low skew, low impedance, differential outputs capable of driv-

ing 110Ohm transmission lines. (RS422 line driver compatible).

They can also be disabled by resetting the device (RST = low).

STA020D DESCRIPTION

The STA020D accepts 16 to 24-bit audio samples through a serial port configured in one of seven formats;

provides several pins dedicated to particular channel status bits and allows all channel status, user and

validity bits to be serially input through port pins. This data is multiplexed, the parity bit is generated and

the bit stream is biphase-mark encoded and driven through an RS422 line driver.

The STA020D operates as a professional or consumer interface transmitter selectable by pin 2, PRO. As

a professional interface device, the dedicated channel status input pins are defined according to the pro-

fessional standard, and the CRC code (C.S. byte 23) can be internally generated.

As a consumer device, the dedicated channel status input pins are defined according to the consumer

standard. A submode provided under the consumer mode is compact disk, CD, mode. When transmitting

data from a compact disk, the CD subcode port can accept CD subcode data, extract channel status in-

7

6

8

15

10

AUDIO

DATA

PROCESSOR

RESET

CONTROL

11

9

RST

16

V

U

SBF

SBC

SDATA

SCK

FSYNC

8 DEDICATED C.S. BITS

EXTERNAL

CLOCK

5

MCK

STA020

+5V

19

VD+

GND

18

0.1

µF

SERIAL PORT

MODE SELECT

TRANSMITTER

CIRCUIT

M0

23

M1

22

M2

21

TXP

20

TXN

17

D99AU989A

DECODER

SUBCODE

PORT

CHANNEL

STATUS BITS

CONTROL