pca9672 NXP Semiconductors, pca9672 Datasheet - Page 11

• Manufacturer Part Number: pca9672
• Description: Pca9672 Remote 8-bit I/o Expander For Fm I?c-bus With Interrupt And Reset
• Manufacturer: NXP Semiconductors

NXP Semiconductors
PCA9672_2
Product data sheet
8.4 Power-on reset
8.5 Interrupt output (INT)
8.6 RESET input
When power is applied to V
a reset condition until V
and the PCA9672 registers and I
states. Thereafter V
The PCA9672 provides an open-drain interrupt (INT) which can be fed to a corresponding
input of the microcontroller (see
chips a kind of master function which can initiate an action elsewhere in the system.
An interrupt is generated by any rising or falling edge of the port inputs. After time t
signal INT is valid.
The interrupt disappears when data on the port is changed to the original setting or data is
read from or written to the device which has generated the interrupt.
In the write mode, the interrupt may become deactivated (HIGH) on the rising edge of the
write to port pulse. On the falling edge of the write to port pulse the interrupt is definitely
deactivated (HIGH).
The interrupt is reset in the read mode on the rising edge of the read from port pulse.
During the resetting of the interrupt itself, any changes on the I/Os may not generate an
interrupt. After the interrupt is reset any change in I/Os will be detected and transmitted as
an INT.
A reset can be accomplished by holding the RESET pin LOW for a minimum of t
PCA9672 registers and I
RESET input is once again HIGH.
Fig 14. Application of multiple PCA9672s with interrupt
MICROCOMPUTER
Remote 8-bit I/O expander for Fm+ I
DD
INT
must be lowered below 0.2 V to reset the device.
DD
Rev. 02 — 6 July 2007
2
C-bus state machine will be held in their default state until the
has reached V
DD
V
DD
, an internal Power-On Reset (POR) holds the PCA9672 in
Figure
2
C-bus/SMBus state machine will initialize to their default
PCA9672
device 1
INT
12,
POR
Figure
. At that point, the reset condition is released
PCA9672
device 2
13, and
INT
2
C-bus with interrupt and reset
Figure
14). This gives these
PCA9672
© NXP B.V. 2007. All rights reserved.
PCA9672
device 8
002aac328
INT
w(rst)
v(D)
11 of 27
. The
the