Datasheet

PCF8574_PCF8574A All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved.
Product data sheet Rev. 5 — 27 May 2013 18 of 33
NXP Semiconductors
PCF8574; PCF8574A
Remote 8-bit I/O expander for I
2
C-bus with interrupt
Rise and fall times refer to V
IL
and V
IH
.
Fig 17. I
2
C-bus timing diagram
002aab175
protocol
START
condition
(S)
bit 7
MSB
(A7)
bit 6
(A6)
bit 0
(R/W)
acknowledge
(A)
STOP
condition
(P)
SCL
SDA
t
HD;STA
t
SU;DAT
t
HD;DAT
t
f
t
BUF
t
SU;STA
t
LOW
t
HIGH
t
VD;ACK
t
SU;STO
1 / f
SCL
t
r
t
VD;DAT
0.3 × V
DD
0.7 × V
DD
0.3 × V
DD
0.7 × V
DD