AD1847

REV. B

–6–

PIN DESCRIPTIONS

Parallel Interface

Pin Name

PLCC

TQFP

I/O

Description

SCLK

1

39

I/O

Serial Clock. SCLK is a bidirectional signal that supplies the clock as an output to the

serial bus when the Bus Master (BM) pin is driven HI and accepts the clock as an input

when the BM pin is driven LO. The serial clock output is fixed at 12.288 MHz when

XTAL1 is selected, and 11.2896 MHz when XTAL2 is selected. SCLK runs continu-

ously. An AD1847 should always be configured as the serial bus master unless it is a slave

in a daisy-chained multiple codec system.

SDFS

6

44

I/O

Serial Data Frame Sync. SDFS is a bidirectional signal that supplies the frame synchroni-

zation signal as an output to the serial bus when the Bus Master (BM) pin is driven HI

and accepts the frame synchronization signal as an input when the BM pin is driven LO.

The SDFS frequency powers up at one half of the AD1847 sample rate (i.e., FRS bit = 0)

with two samples per frame and can be programmed to match the sample rate (i.e., FRS

bit = 1) with one sample per frame. An AD1847 should always be configured as the serial

bus master unless it is a slave in a daisy-chained multiple codec system.

SDI

4

42

I

Serial Data Input. SDI is used by peripheral devices such as the host CPU or a DSP to

supply control and playback data information to the AD1847. All control and playback

transfers are 16 bits long, MSB first.

SDO

5

43

O

Serial Data Output. SDO is used to supply status/index readback and capture data infor-

mation to peripheral devices such as the host CPU or a DSP. All status/index readback

and capture data transfers are 16 bits long, MSB first. Three-state output driver.

RESET

11

5

I

Reset. The RESET signal is active LO. The assertion of this signal will initialize the

on-chip registers to their default values. See the “Control Register Definitions” section for

a description of the contents of the control registers after RESET is deasserted.

PWRDOWN

12

6

I

Powerdown. The PWRDOWN signal is active LO. The assertion of this signal will reset

the on-chip control registers (identically to the RESET signal) and will also place the

BM

33

27

I

Bus Master. The assertion (HI) of this signal indicates that the AD1847 is the serial bus

master. The AD1847 will then supply the serial clock (SCLK) and the frame sync (SDFS)

signals for the serial bus. One and only one AD1847 should always be configured as the

serial bus master. If BM is connected to logic LO, the AD1847 is configured as a bus

slave, and will accept the SCLK and SDFS signals as inputs. An AD1847 should only be

configured as a serial bus slave when an AD1847 serial bus master already exists, in

daisy-chained multiple codec systems.

TSO

7

1

O

Time Slot Output. This signal is asserted HI by the AD1847 coincidentally with the LSB

of the last time slot used by the AD1847. Used in daisy-chained multiple codec systems.

TSI

8

2

I

Time Slot Input. The assertion of this signal indicates that the AD1847 should immedi-

ately use the next three time slots (TSSEL = 1) or the next six time slots (TSSEL = 0)

and then activate the TSO pin to enable the next device down the TDM chain. TSI

should be driven LO when the AD1847 is the bus master or in single codec systems. Used

in daisy-chained multiple codec systems.

CLKOUT

44

38

O

Clock Output. This signal is the buffered version of the crystal clock output and the fre-

quency is dependent on which crystal is selected. This pin can be three-stated by driving

the BM pin LO or by programming the CLKTS bit in the Pin Control Register. See the

“Control Registers” section for more details. The CLKOUT frequency is 12.288 MHz

when XTAL1 is selected and 16.9344 MHz when XTAL2 is selected.

Analog Signals

Pin Name

PLCC

TQFP

I/O

Description

L_LINE1

23

17

I

Left Line Input #1. Line level input for the #1 left channel.

R_LINE1

17

11

I

Right Line Input #1. Line level input for the #1 right channel.

L_LINE2

22

16

I

Left Line Input #2. Line level input for the #2 left channel.

R_LINE2

18

12

I

Right Line Input #2. Line level input for the #2 right channel.

L_AUX1

26

20

I

Left Auxiliary Input #1. Line level input for the AUX1 left channel.

R_AUX1

27

21

I

Right Auxiliary Input #1. Line level input for the AUX1 right channel.

L_AUX2

32

26

I

Left Auxiliary Input #2. Line level input for the AUX2 left channel.

R_AUX2

31

25

I

Right Auxiliary Input #2. Line level input for the AUX2 right channel.

L_OUT

30

24

O

Left Line Output. Line level output for the left channel.

R_OUT

28

22

O

Right Line Output. Line level output for the right channel.