PCA9557 查看數據表（PDF） - Philips Electronics

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PCA9557

8-bit I2C and SMBus I/0 port with reset

Philips Electronics 

Philips Semiconductors

8-bit I2C and SMBus I/0 port with reset

Product data

PCA9557

SDA

READ FROM

PORT

slave address

data from port

S 0 0 1 1 A2 A1 A0 1 A

start condition

R/W acknowledge

from slave

DATA 1

data from port

A

acknowledge

from master

DATA 4

NA P

no acknowledge

from master

stop

condition

DATA INTO

PORT

DATA 2

DATA 3

tph

tps

DATA 4

SW00799

NOTES:

1. This figure assumes the command byte has previously been programmed with 00h.

2. Transfer of data can be stopped at any moment by a stop condition. When this occurs, data present at the last acknowledge phase is valid

(output mode). Input data is lost.

Figure 15. READ input port register

TYPICAL APPLICATION

VDD

VDD

1.6 kΩ

1.6 kΩ 1.1 kΩ

2 kΩ

MASTER

CONTROLLER

SCL

SDA

RESET

GND

VDD

SCL

I/00

SDA

I/01

RESET

I/02

I/03

PCA9557

I/04

I/05

A2

I/06

A1

I/07

A0

GND

NOTE: Device address configured as 0011100 for this example

I/00, I/01, I/02, configured as outputs

I/03, I/04, I/05, configured as inputs

I/006, I/07, are not used and have to be configured as outputs

Figure 16. Typical application

2 kΩ

SUBSYSTEM 1

(e.g. temp sensor)

INT

RESET

SUBSYSTEM 2

(e.g. counter)

A

ENABLE

Controlled Switch

(e.g. CBT device)

B

ALARM

SUBSYSTEM 3

(e.g. alarm

system)

VDD

SW00993

2001 Dec 12

10

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