PCA9535BS 데이터 시트보기 (PDF) - NXP Semiconductors.
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PCA9535BS Datasheet PDF : 34 Pages
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NXP Semiconductors
PCA9535; PCA9535C
16-bit I2C-bus and SMBus, low power I/O port with interrupt
7.2 System configuration
A device generating a message is a ‘transmitter’; a device receiving is the ‘receiver’. The
device that controls the message is the ‘master’ and the devices which are controlled by
the master are the ‘slaves’ (see Figure 15).
SDA
SCL
MASTER
TRANSMITTER/
RECEIVER
SLAVE
RECEIVER
SLAVE
TRANSMITTER/
RECEIVER
MASTER
TRANSMITTER
MASTER
TRANSMITTER/
RECEIVER
I2C-BUS
MULTIPLEXER
SLAVE
Fig 15. System configuration
002aaa966
7.3 Acknowledge
The number of data bytes transferred between the START and the STOP conditions from
transmitter to receiver is not limited. Each byte of eight bits is followed by one
acknowledge bit. The acknowledge bit is a HIGH level put on the bus by the transmitter,
whereas the master generates an extra acknowledge related clock pulse.
A slave receiver which is addressed must generate an acknowledge after the reception of
each byte. Also a master must generate an acknowledge after the reception of each byte
that has been clocked out of the slave transmitter. The device that acknowledges has to
pull down the SDA line during the acknowledge clock pulse, so that the SDA line is stable
LOW during the HIGH period of the acknowledge related clock pulse; set-up time and hold
time must be taken into account.
A master receiver must signal an end of data to the transmitter by not generating an
acknowledge on the last byte that has been clocked out of the slave. In this event, the
transmitter must leave the data line HIGH to enable the master to generate a STOP
condition.
data output
by transmitter
data output
by receiver
SCL from master
1
2
S
START
condition
Fig 16. Acknowledgement on the I2C-bus
not acknowledge
acknowledge
8
9
clock pulse for
acknowledgement
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PCA9535_PCA9535C
Product data sheet
All information provided in this document is subject to legal disclaimers.
Rev. 6 — 7 November 2017
© NXP Semiconductors N.V. 2017. All rights reserved.
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