Datasheet

PCA9557 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved.
Product data sheet Rev. 7 — 10 December 2013 3 of 30
NXP Semiconductors
PCA9557
8-bit I
2
C-bus and SMBus I/O port with reset
On power-up or reset, all registers return to default values.
Fig 2. Simplified schematic of IO0
IO0
output port
register data
configuration
register
DQ
CK Q
data from
shift register
write configuration
pulse
output port
register
DQ
CK
write pulse
polarity inversion
register
DQ
CK
data from
shift register
write polarity
pulse
input port
register
DQ
CK
read pulse
input port
register data
polarity inversion
register data
002aad277
FF
data from
shift register
FF
FF
FF
V
SS
ESD protection
diode