pca8575 NXP Semiconductors, pca8575 Datasheet - Page 11

• Manufacturer Part Number: pca8575
• Description: Remote 16-bit I/o Expander For I2c-bus With Interrupt
• Manufacturer: NXP Semiconductors

NXP Semiconductors
PCA8575_2
Product data sheet
8.4 Power-on reset
8.5 Interrupt output (INT)
When power is applied to V
a reset condition until V
and the PCA8575 registers and I
states. Thereafter V
The PCA8575 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.
Fig 14. Application of multiple PCA8575s with interrupt
MICROCOMPUTER
DD
INT
Rev. 02 — 21 March 2007
must be lowered below 0.2 V to reset the device.
DD
has reached V
DD
V
DD
, an internal Power-On Reset (POR) holds the PCA8575 in
Figure
2
Remote 16-bit I/O expander for I
C-bus/SMBus state machine will initialize to their default
PCA8575
device 1
INT
12,
POR
Figure
. At that point, the reset condition is released
PCA8575
device 2
13, and
INT
Figure
14). This gives these
2
C-bus with interrupt
PCA8575
© NXP B.V. 2007. All rights reserved.
PCA8575
device 8
002aac676
INT
v(D)
11 of 30
the