PCA9501 查看數據表（PDF） - Philips Electronics

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PCA9501

8-bit I2C and SMBus I/O port with interrupt, 2-kbit EEPROM and 6 address pins

Philips Electronics 

Philips Semiconductors

8-bit I2C and SMBus I/O port with interrupt,

2-kbit EEPROM and 6 address pins

Product data

PCA9501

Quasi-bidirectional I/Os (see Figure 8)

A quasi-bidirectional I/O can be used as an input or output without the use of a control signal for data direction. At power-on the I/Os are HIGH.

In this mode, only a current source to VDD is active. An additional strong pull-up to VDD allows fast rising edges into heavily loaded outputs.

These devices turn on when an output is written HIGH, and are switched off by the negative edge of SCL. The I/Os should be HIGH before

being used as inputs.

SLAVE ADDRESS (I/O EXPANDER)

DATA TO PORT

SDA S 0 A5 A4 A3 A2 A1 A0 0 A

1

START CONDITION

R/W ACKNOWLEDGE

I/O3

FROM SLAVE

SCL

12 345 678

DATA TO PORT

A

0

ACKNOWLEDGE

I/O3

FROM SLAVE

AP

I/O3

OUTPUT

VOLTAGE

I/O3

PULL-UP

OUTPUT

CURRENT

IOHt

IOH

Figure 8. Transient pull-up current IOHt while I/O3 changes from LOW-to-HIGH and back to LOW

SW00904

2003 Sep 12

7

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