PCA9671BS NXP [NXP Semiconductors], PCA9671BS Datasheet - Page 17
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PCA9671BS
Manufacturer Part Number
PCA9671BS
Description
Remote 16-bit I/O expander for Fm+ I2C-bus with reset
Manufacturer
NXP [NXP Semiconductors]
Datasheet
1.PCA9671BS.pdf
(34 pages)
NXP Semiconductors
PCA9671_1
Product data sheet
Fig 21. System configuration
SDA
SCL
TRANSMITTER/
RECEIVER
MASTER
9.2 System configuration
9.3 Acknowledge
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
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 and hold
times 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.
Fig 20. Definition of START and STOP conditions
SDA
SCL
RECEIVER
SLAVE
START condition
S
Rev. 01 — 20 December 2006
TRANSMITTER/
RECEIVER
SLAVE
Remote 16-bit I/O expander for Fm+ I
Figure
TRANSMITTER
21).
MASTER
TRANSMITTER/
RECEIVER
MASTER
SLAVE
STOP condition
P
MULTIPLEXER
PCA9671
© NXP B.V. 2006. All rights reserved.
2
I
2
C-bus with reset
C-BUS
002aaa966
mba608
SDA
SCL
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