m41t83 STMicroelectronics, m41t83 Datasheet - Page 16

• Manufacturer Part Number: m41t83
• Description: Serial I 2c Bus Rtc With Battery Switchover
• Manufacturer: STMicroelectronics

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Acknowledge
Each byte of eight bits is followed by one Acknowledge bit. This Acknowledge bit is a low
level put on the bus by the receiver whereas the master generates an extra acknowledge
related clock pulse. A slave receiver which is addressed is obliged to 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 in such a way that the SDA line is a stable Low during the High period of the
acknowledge related clock pulse. Of course, setup and hold times must be taken into
account. A master receiver must signal an end of data to the slave transmitter by not
generating an acknowledge on the last byte that has been clocked out of the slave. In this
case the transmitter must leave the data line High to enable the master to generate the
STOP condition.
Figure 10. Serial bus data transfer sequence
Figure 11. Acknowledgement sequence
SCL FROM
MASTER
DATA OUTPUT
BY TRANSMITTER
DATA OUTPUT
BY RECEIVER
CLOCK
DATA
CONDITION
START
START
MSB
1
DATA VALID
DATA LINE
STABLE
DATA ALLOWED
CHANGE OF
2
LSB
8
ACKNOWLEDGEMENT
CLOCK PULSE FOR
CONDITION
STOP
9
AI00587
AI00601