PCA8575 查看數據表（PDF） - Philips Electronics

零件编号

产品描述 (功能)

生产厂家

PCA8575

Remote 16-bit I/O expander for I2C-bus with interrupt

Philips Electronics 

NXP Semiconductors

PCA8575

Remote 16-bit I/O expander for I2C-bus with interrupt

8.4 Power-on reset

When power is applied to VDD, an internal Power-On Reset (POR) holds the PCA8575 in

a reset condition until VDD has reached VPOR. At that point, the reset condition is released

and the PCA8575 registers and I2C-bus/SMBus state machine will initialize to their default

states. Thereafter VDD must be lowered below 0.2 V to reset the device.

8.5 Interrupt output (INT)

The PCA8575 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.

An interrupt is generated by any rising or falling edge of the port inputs. After time tv(D) the

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.

VDD

MICROCOMPUTER

INT

device 1

PCA8575

INT

device 2

PCA8575

INT

Fig 14. Application of multiple PCA8575s with interrupt

device 8

PCA8575

INT

002aac676

PCA8575_1

Objective data sheet

Rev. 01 — 30 November 2006

© NXP B.V. 2006. All rights reserved.

11 of 30

Share Link: