PCA9500 View Datasheet(PDF) - Philips Electronics
Part Name
Description
Manufacturer
PCA9500 Datasheet PDF : 23 Pages
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Philips Semiconductors
8-bit I2C and SMBus I/O port with 2-kbit EEPROM
Product data sheet
PCA9500
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 1 0 0 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
SW00905
2004 Sep 30
6
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