pca9670 NXP Semiconductors, pca9670 Datasheet - Page 12

• Manufacturer Part Number: pca9670
• Description: Pca9670 Remote 8-bit I/o Expander For Fm I?c-bus With Reset
• Manufacturer: NXP Semiconductors

NXP Semiconductors
PCA9670_2
Product data sheet
Fig 13. Read input port register
read from
data into
port
port
A LOW-to-HIGH transition of SDA while SCL is HIGH is defined as the STOP condition (P). 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.
SDA
8.3 Reading from a port (Input mode)
8.4 Power-on reset
8.5 RESET input
S A6
START condition
All ports programmed as input should be set to logic 1. To read, the master
(microcontroller) first addresses the slave device after it receives the interrupt. By setting
the last bit of the byte containing the slave address to logic 1 the Read mode is entered.
The data bytes that follow on the SDA are the values on the ports.
If the data on the input port changes faster than the master can read, this data may be
lost.
When power is applied to V
a reset condition until V
and the PCA9670 registers and I
states. Thereafter V
A reset can be accomplished by holding the RESET pin LOW for a minimum of t
PCA9670 registers and I
RESET input is once again HIGH.
A5 A4 A3 A2 A1 A0 1
slave address
t
h(D)
R/W
DD
A
acknowledge
from slave
must be lowered below 0.2 V to reset the device.
DD
Rev. 02 — 17 July 2007
2
C-bus state machine will be held in their default state until the
has reached V
DD
DATA 2
, an internal Power-On Reset (POR) holds the PCA9670 in
data from port
DATA 1
2
Remote 8-bit I/O expander for Fm+ I
C-bus/SMBus state machine will initialize to their default
DATA 3
t
su(D)
POR
. At that point, the reset condition is released
A
acknowledge
from master
data from port
DATA 4
DATA 4
PCA9670
© NXP B.V. 2007. All rights reserved.
2
C-bus with reset
1
no acknowledge
from master
002aac266
P
STOP
condition
w(rst)
12 of 28
. The