PCF8574AT NXP Semiconductors, PCF8574AT Datasheet - Page 8

• Manufacturer Part Number: PCF8574AT
• Manufacturer: NXP Semiconductors

Specifications of PCF8574AT

• Operating Temperature (min): -40C
• Operating Temperature Classification: Industrial
• Operating Temperature (max): 85C
• Package Type: SO
• Rad Hardened: No
• Lead Free Status / Rohs Status: Compliant

Philips Semiconductors
6.4
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 (see Fig.8). 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
2002 Nov 22
handbook, full pagewidth
Remote 8-bit I/O expander for I
Acknowledge
BY TRANSMITTER
DATA OUTPUT
DATA OUTPUT
BY RECEIVER
SCL FROM
MASTER
condition
START
S
Fig.8 Acknowledgment on the I
2
C-bus
1
8
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.
2
2
C-bus.
not acknowledge
acknowledge
8
acknowledgement
clock pulse for
9
MBC602
Product specification
PCF8574