pcf2127a NXP Semiconductors, pcf2127a Datasheet - Page 57

• Manufacturer Part Number: pcf2127a
• Description: Integrated Rtc, Tcxo And Quartz Crystal
• Manufacturer: NXP Semiconductors

NXP Semiconductors
PCF2127A_1
Product data sheet
Fig 40. System configuration
SDA
SCL
9.2.4 Acknowledge
TRANSMITTER
RECEIVER
MASTER
The PCF2127A can act as a slave transmitter and a slave receiver.
The number of data bytes transferred between the START and STOP conditions from
transmitter to receiver is unlimited. Each byte of eight bits is followed by an acknowledge
cycle.
Acknowledgement on the I
Fig 41. Acknowledgement on the I
•
•
•
•
A slave receiver, which is addressed, must generate an acknowledge after the
reception of each byte.
Also a master receiver must generate an acknowledge after the reception of each
byte that has been clocked out of the slave transmitter.
The device that acknowledges must 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
consideration).
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.
by transmitter
data output
data output
by receiver
SCL from
master
RECEIVER
SLAVE
condition
START
Rev. 01 — 21 January 2010
S
2
C-bus is illustrated in
TRANSMITTER
RECEIVER
SLAVE
1
2
C-bus
Integrated RTC, TCXO and quartz crystal
2
TRANSMITTER
Figure
MASTER
41.
not acknowledge
acknowledge
8
TRANSMITTER
PCF2127A
RECEIVER
MASTER
acknowledgement
clock pulse for
© NXP B.V. 2010. All rights reserved.
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