Cirrus-logic AN259 Instrukcja Użytkownika Pobierz pdf (Strona 4)

AN259

4 AN259REV2

alog filter gain (if similar output level to the CS4382 is desired).

- The mute control pins are high impedance while reset is asserted. An external pull-up or down is

required to properly bias the off-chip mute circuit into muting during reset.

- The dual serial port function of the CS4382 which accepted two simultaneous synchronous sam-

ple rates (such as 192 kHz front and 96 kHz surrounds) is not supported.

2.2 Transitioning from the CS4382 to CS4385

2.2.1 Hardware changes

The CS4385 pinout was primarily based on the CS4382 with only 3 pins changing function. Other pins

have new recommended components but the circuit topologies remain the same and thus do not

require modification to the PCB. The most significant change is that the VD core of the CS4385

requires 2.5 V for operation, whereas the CS4382 was able to run from 3.3 V to 5 V. The CS4385 will

NOT operate off of a VD supply of 3.3 V or 5 V.

Figure 3 and Figure 4 show the CS4382 and CS4385 pinouts respectively. The changes to the two

pinouts are highlighted. Figure 3 highlights the pins which have changed function and which may

require a PCB change. Figure 4 highlights the pins which have new recommended components.

Location or function changes as denoted in Figure 3 are as follows:

• Pin 7 is no longer DSD_EN in hardware mode. In order to enter DSD mode on the CS4385 you must either

set the M4 and M3 pins accordingly or use SPI™ or I

C configuration.

• The CS4385 does not support the simultaneous synchronous sample rate function of the CS4382. Pins 10

and 12 are now dedicated for stand-alone configuration (voltage input on these pins are still referenced to

VLS).

• Pin 42 no longer functions as M3 in stand-alone PCM modes. It is now a dedicated DSD_SCLK pin.

SDIN3

GND

AOUTB2-

AOUTA3+

AOUTB3-

AOUTB2+

AOUTA3-

AOUTB3+

13 14 15 16 17 18 19 20 21 22 23 24

48 47 46 45 44 43 42 41 40 39 38 37

MCLK

DSDB1

SDIN1

LRCK2

DSDA2

DSDA1

GND

SCLK1

SDIN2

SCLK2

LRCK1(DSD_EN)

M3(DSD_SCLK)

DSDB3

DSDA3

DSDA4

CS4382

DSDB4

VLS

SDIN4

M2(SCL/CCLK)

M1(SDA/CDIN)

VLC

RST

FILT+

MUTEC234

M0(AD0/CS)

AOUTA2+

AOUTA2-

AOUTB1+

AOUTB1-

AOUTA1-

AOUTA1+

DSDB2

MUTEC1

AOUTA4-

AOUTA4+

AOUTB4+

AOUTB4-

= denotes location or function changes

when trasitioning to CS4385

Figure 3. CS4382 pinout