pca9506 NXP Semiconductors, pca9506 Datasheet - Page 15

• Manufacturer Part Number: pca9506
• Description: 40-bit I2c-bus I/o Port With Reset, Oe, And Int
• Manufacturer: NXP Semiconductors

Philips Semiconductors
9397 750 14939
Product data sheet
Fig 9. System configuration
SDA
SCL
TRANSMITTER/
RECEIVER
MASTER
8.3 Acknowledge
8.4 Bus transactions
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.
Data is transmitted to the PCA9506 registers using Write Byte transfers (see
Figure
Receive Byte transfers (see
Fig 10. Acknowledgement on the I
12, and
RECEIVER
SLAVE
SCL from master
by transmitter
data output
Figure
data output
by receiver
Rev. 01 — 14 February 2006
TRANSMITTER/
13). Data is read from the PCA9506 registers using Read and
RECEIVER
condition
START
SLAVE
S
Figure
2
C-bus
14).
TRANSMITTER
1
40-bit I
MASTER
2
C-bus I/O port with RESET, OE, and INT
2
TRANSMITTER/
RECEIVER
MASTER
acknowledgement
not acknowledge
© Koninklijke Philips Electronics N.V. 2006. All rights reserved.
SLAVE
clock pulse for
acknowledge
8
MULTIPLEXER
PCA9506
002aaa987
I
2
9
C-BUS
002aaa966
Figure
15 of 30
11,