PCA9672_2

© NXP B.V. 2007. All rights reserved.

Product data sheet

Rev. 02 — 6 July 2007

11 of 27

NXP Semiconductors

PCA9672

8.4 Power-on reset

8.5 Interrupt output (INT)

The PCA9672 provides an open-drain interrupt (INT) which can be fed to a corresponding

input of the microcontroller (see Figure 12, Figure 13, and Figure 14). This gives these

chips a kind of master function which can initiate an action elsewhere in the system.

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.

8.6 RESET input

RESET input is once again HIGH.

Fig 14. Application of multiple PCA9672s with interrupt

002aac328

MICROCOMPUTER

INT

PCA9672

INT

PCA9672

INT

device 1

device 2

PCA9672

INT

device 8