pcf2129a NXP Semiconductors, pcf2129a Datasheet - Page 48

• Manufacturer Part Number: pcf2129a
• Description: Integrated Rtc, Tcxo And Quartz Crystal
• Manufacturer: NXP Semiconductors

NXP Semiconductors
PCF2129A_1
Product data sheet
Fig 33. System configuration
SCL
SDA
9.2.4 Acknowledge
9.2.5 I
TRANSMITTER
RECEIVER
MASTER
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
After a start condition a valid hardware address has to be sent to a PCF2129A device.
The appropriate I
is shown in
2
Fig 34. Acknowledgement on the I
•
•
•
•
C-bus protocol
A slave receiver, which is addressed, must generate an acknowledge after the
reception of each byte.
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
by receiver
data output
SCL from
master
Table
RECEIVER
SLAVE
2
50.
C-bus slave address is 1010001. The entire I
condition
START
Rev. 01 — 13 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
34.
not acknowledge
acknowledge
2
8
C-bus slave address byte
TRANSMITTER
PCF2129A
RECEIVER
MASTER
acknowledgement
clock pulse for
© NXP B.V. 2010. All rights reserved.
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