PCA9673_1

© NXP B.V. 2007. All rights reserved.

Product data sheet

Rev. 01 — 1 February 2007

14 of 33

NXP Semiconductors

PCA9673

8.4 Power-on reset

8.5 Interrupt output (INT)

The PCA9673 provides an open-drain interrupt (INT) which can be fed to a corresponding

input of the microcontroller (see Figure 17, Figure 18, and Figure 19). 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 19. Application of multiple PCA9673s with interrupt

002aac308

MICROCOMPUTER

INT

PCA9673

INT

PCA9673

INT

device 1

device 2

PCA9673

INT

device 8