参数资料
型号: PCA8574TS,112
厂商: NXP Semiconductors
文件页数: 2/32页
文件大小: 0K
描述: IC I/O EXPANDER I2C 8B 20SSOP
特色产品: NXP - I2C Interface
标准包装: 75
接口: I²C
输入/输出数: 8
中断输出:
频率 - 时钟: 400kHz
电源电压: 2.3 V ~ 5.5 V
工作温度: -40°C ~ 85°C
安装类型: 表面贴装
封装/外壳: 20-LSSOP(0.173",4.40mm 宽)
供应商设备封装: 20-SSOP
包装: 管件
包括: POR
其它名称: 568-4242-5
935283487112
PCA8574TS
PCA8574_PCA8574A
All information provided in this document is subject to legal disclaimers.
NXP B.V. 2013. All rights reserved.
Product data sheet
Rev. 3 — 3 June 2013
10 of 32
NXP Semiconductors
PCA8574; PCA8574A
Remote 8-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 PCA8574;
PCA8574A in a reset condition until VDD has reached VPOR. At that point, the reset
condition is released and the PCA8574; PCA8574A registers and I2C-bus/SMBus state
machine will initialize to their default states of all I/Os to inputs with weak current source to
VDD. Thereafter VDD must be lowered below VPOR and back up to the operation voltage for
power-on reset cycle.
8.5 Interrupt output (INT)
The PCA8574/74A provides an open-drain output (INT) which can be fed to a
corresponding input of the microcontroller (see Figure 10). As soon as a port input is
changed, the INT will be active (LOW) and notify the microcontroller.
An interrupt is generated at any rising or falling edge of the port inputs. After time tv(Q), the
signal INT is valid.
The interrupt will reset to HIGH when data on the port is changed to the original setting or
data is read or written by the master.
In the Write mode, the interrupt may be reset (HIGH) on the rising edge of the
acknowledge bit of the data byte and also on the rising edge of the write to port pulse. The
interrupt will always be reset (HIGH) on the falling edge of the write to port pulse (see
The interrupt is reset (HIGH) in the Read mode on the rising edge of the acknowledge of
slave address byte and on the rising edge of the read from port pulse (see Figure 9).
During the interrupt reset, any I/O change close to the read or write pulse may not
generate an interrupt, or the interrupt will have a very short pulse. After the interrupt is
reset, any change in I/Os will be detected and transmitted as an INT.
At power-on reset all ports are in Input mode and the initial state of the ports is HIGH,
therefore, for any port pin that is pulled LOW or driven LOW by external source, the
interrupt output will be active (output LOW).
Fig 10. Application of multiple PCA8574/74As with interrupt
002aac682
VDD
MICROCONTROLLER
INT
PCA8574
INT
PCA8574
INT
device 1
device 2
PCA8574A
INT
device 16
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PCA8575BQ,118 功能描述:接口-I/O扩展器 16-BIT I2C FM QB RoHS:否 制造商:NXP Semiconductors 逻辑系列: 输入/输出端数量: 最大工作频率:100 kHz 工作电源电压:1.65 V to 5.5 V 工作温度范围:- 40 C to + 85 C 安装风格:SMD/SMT 封装 / 箱体:HVQFN-16 封装:Reel
PCA8575BQ-T 功能描述:接口-I/O扩展器 16-BIT I2C FM QB GPIO INT PU RoHS:否 制造商:NXP Semiconductors 逻辑系列: 输入/输出端数量: 最大工作频率:100 kHz 工作电源电压:1.65 V to 5.5 V 工作温度范围:- 40 C to + 85 C 安装风格:SMD/SMT 封装 / 箱体:HVQFN-16 封装:Reel