CX20921 AudioSmart Data Sheet

Pin Information

Conexant Confidential

03/11/15

001DSR01

7

Pin Signal Definitions

Table 1 provides the CX20921 pin description. The following lists the acronyms used in this table:

•

AI = Analog In

•

AO = Analog Out

•

DI = Digital In

•

DIO = Digital Input/Output

•

DO = Digital Out

•

PD = Pull-Down

•

PU = Pull-Up

•

PWR = Power

Table 1: Pin Signal Definitions

Label

Pin

Number

I/O Type

Signal Name/Description

I2S

I2S_TX_DATA_1

1

DO

I2S Transmit Data. Master/slave configurable using the control

interface.

I2S_TX_LRCK

2

DIO

I2S Transmit Frame. Master/slave configurable using the

control interface.

I2S_TX_CLK

3

DIO

I2S Transmit Clock. Master/slave configurable using the control

interface.

DC-DC Controller

DCDC_PVSS

6

Ground

DC-DC Power Ground.

DCDC_SW

7

PWR

DC-DC Switch Pin. Connect to the external filtering as indicated

on the reference schematic.

PVDD33

8

PWR

DC-DC 3.3V Power Stage Input Power Supply Input. 3.3V—

Connect to the external decoupling capacitor and system 3.3V.

DCDC_IREF

10

AO

DC-DC Current Reference. 3.3V—Connect to the PD 301K

resistor.

DCDC_EN

11

AI

DC-DC Enable Pin. Output voltage from Low Drop-Out (LDO).

Enables 3.3V to 1V buck conversion.

DCDC_FB

12

AI

DC-DC Buck Output Feedback Scaled-Down Pin.

AVDD33

13

PWR

DC-DC Analog Power Pin. 3.3V—Connect to the external

decoupling capacitor and system 3.3V.

UART Interface

TXD

14

DO

UART Serial Transmission Data.

RXD

15

DI

UART Serial Receiving Data.

CTS

16

DI

UART Clear-to-Send (CTS). Muxed with the DMIC_DATA and

I2S_TX_LRCK2 signals.

RTS

17

DO

UART Request-to-Send (RTS). Muxed with the DMIC_CLK and

I2S_TX_DATA_2 signals.

General GPIO

GPIO_1

18

DIO

General Purpose IO. Programmable PU and drive control.

GPIO_2

19

DIO

General Purpose IO. Programmable PU and drive control. This

pin is muxed with the I2S_TX_CLK2 signal.