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參數(shù)資料
| 型號： | PCF8574T |
| 廠商： | NXP Semiconductors N.V. |
| 元件分類： | I2C/I2S |
| 英文描述： | Remote 8-bit I-O expander for I2C-bus |
| 封裝： | PCF8574AP<SOT38-4 (DIP16)|<<http://www.nxp.com/packages/SOT38-4.html<1<Always Pb-free,;PCF8574AT/3<SOT162-1 (SO16)|<<http://www.nxp.com/packages/SOT162-1.html<1<wee |
| 文件頁數(shù)： | 12/24頁 |
| 文件大?。?/td> | 132K |
| 代理商： | PCF8574T |
2002 Nov 22
12
Philips Semiconductors
Product specification
Remote 8-bit I/O expander for I
2
C-bus
PCF8574
7.2
Interrupt output
The PCF8574 provides an open-drain output (INT) which
can be fed to a corresponding input of the microcontroller
(see Figs 13 and 14). This gives these chips a type of
master function which can initiate an action elsewhere in
the system.
Aninterruptisgeneratedbyanyrisingorfallingedgeofthe
port inputs in the input mode. After time t
iv
the signal INT is
valid.
Resetting and reactivating the interrupt circuit is achieved
when data on the port is changed to the original setting or
dataisreadfromorwrittentotheportwhichhasgenerated
the interrupt.
Resetting occurs as follows:
IntheREADmodeattheacknowledgebitaftertherising
edge of the SCL signal
In the WRITE mode at the acknowledge bit after the
HIGH-to-LOW transition of the SCL signal
Interrupts which occur during the acknowledge clock
pulse may be lost (or very short) due to the resetting of
the interrupt during this pulse.
Each change of the I/Os after resetting will be detected
and, after the next rising clock edge, will be transmitted as
INT. Reading from or writing to another device does not
affect the interrupt circuit.
7.3
Quasi-bidirectional I/Os
A quasi-bidirectional I/O can be used as an input or output
without the use of a control signal for data direction
(see Fig.15). At power-on the I/Os are HIGH. In this mode
only a current source to V
DD
is active. An additional strong
pull-up to V
DD
allows fast rising edges into heavily loaded
outputs. These devices turn on when an output is written
HIGH, and are switched off by the negative edge of SCL.
The I/Os should be HIGH before being used as inputs.
handbook, full pagewidth
MBD976
MICROCONTROLLER
INT
INT
INT
PCF8574
(1)
PCF8574
(2)
VDD
INT
PCF8574
(16)
Fig.13 Application of multiple PCF8574s with interrupt.
Fig.14 Interrupt generated by a change of input to I/O P5.
handbook, full pagewidth
MBD972
S
0
1
0
0
A2
A1
A0
1
A
start condition
1
P5
R/W
acknowledge
from slave
1
SDA
SCL
DATA INTO
P5
tir
INT
slave address (PCF8574)
data from port
1
2
3
4
5
6
7
8
P
stop
condition
tiv
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相關(guān)代理商/技術(shù)參數(shù) |
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| PCF8574T K72741 | 制造商:NXP Semiconductors 功能描述: |
| PCF8574T | 制造商:NXP Semiconductors 功能描述:IC SM I/O EXPANDER 8-BIT |
| PCF8574T/3 | 制造商:NXP Semiconductors 功能描述:I/O Expander 16-Pin SO 制造商:NXP Semiconductors 功能描述:I/O Expander 16-Pin SO Bulk 制造商:NXP Semiconductors 功能描述:I/O EXPANDER 8BIT REMOTE SO-16 制造商:NXP Semiconductors 功能描述:I/O EXPANDER, 8BIT REMOTE, SO-16 |
| PCF8574T/3,512 | 功能描述:I2C 接口集成電路 REMOTE I/O EXPANDER RoHS:否 制造商:NXP Semiconductors 電源電壓-最大:5.5 V 電源電壓-最小:2.3 V 最大工作頻率:400 KHz 最大工作溫度:+ 85 C 封裝 / 箱體:TSSOP-16 |
| PCF8574T/3,518 | 功能描述:接口-I/O擴展器 I/O EXPANDER I2C RoHS:否 制造商:NXP Semiconductors 邏輯系列: 輸入/輸出端數(shù)量: 最大工作頻率:100 kHz 工作電源電壓:1.65 V to 5.5 V 工作溫度范圍:- 40 C to + 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:HVQFN-16 封裝:Reel |
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