STFPC320 STMicroelectronics, STFPC320 Datasheet - Page 20

• Manufacturer Part Number: STFPC320
• Description: Front Panel Controller/driver With Standby Power Management And Real-time Clock
• Manufacturer: STMicroelectronics

Real Time Clock (RTC) operation
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Figure 9.
Figure 10. Acknowledgement sequence
condition. The number of data bytes transferred between the start and stop conditions
is not limited. The information is transmitted byte-wide and each receiver acknowledges
with a ninth bit.
By definition a device that gives out a message is called “transmitter,” the receiving
device that gets the message is called “receiver.” The device that controls the message
is called “master.” The devices that are controlled by the master are called “slaves.”
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 master 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.
Serial bus data transfer sequence
STFPC320